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  • 1
    Electronic Resource
    Electronic Resource
    Isolation and functional analysis of a set of auxin genes with low root-inducing activity from an Agrobacterium tumefaciens biotype III strain (1989)
    Springer
    Plant molecular biology 12 (1989), S. 271-283 
    Details
    ISSN: 1573-5028
    Keywords: Agrobacterium ; auxins ; roots ; oncogenes ; grapevine ; iaa genes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A new type of root-inducing iaa gene set was cloned from the Ti plasmid of the biotype III Agrobacterium tumefaciens strain Tm-4. These iaa genes are characterized by a very low DNA homology with the well-characterized iaa gene set, iaaM and iaaH, of the “common DNA” region of the biotype I strain Ach5 and by a low root-inducing activity. The biological activities of both iaa gene sets were compared by transferring each into a disarmed Ti vector and by testing the resulting strains on Nicotiana rustica leaf discs, decapitated Datura stramonium stems, tomato plants and Kalanchoë daigremontiana. Tm-4 iaa genes have a reproducibly weaker root-inducing ability on Nicotiana rustica, induce very little tumour growth on decapitated Datura plants or on tomato plants and do not induce roots on Kalanchoë daigremontiana. The Tm-4 iaa region was mapped by λ:: Tn5 transposon mutagenesis and tested on Nicotiana rustica. These tests combined with complementation experiments map the iaa genes to a 4.5-kb region. The Tm-4 iaa genes were able to complement the corresponding Ach5 iaa genes on Nicotiana rustica, indicating that the differences between these genes are quantitative rather than qualitative. Complementation experiments on Kalanchoë showed the iaaM gene of Tm-4 responsible for the overall weak auxin activity of the intact iaa set. In view of the observed structural and functional differences we propose to call the Tm-4 iaa genes TB-iaaM and TB-iaaH and the Ach5 iaa genes A-iaaM and A-iaaH.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00043204
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  • 2
    Electronic Resource
    Electronic Resource
    Specificity of Agrobacterium-mediated delivery of maize streak virus DNA to members of the Gramineae (1989)
    Springer
    Plant molecular biology 12 (1989), S. 31-40 
    Details
    ISSN: 1573-5028
    Keywords: agroinfection ; Agrobacterium ; strains ; maize streak virus ; Gramineae ; maize
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Parameters affecting the efficiency of agroinfection of maize streak virus (MSV) in maize have been determined. Monomeric units, cloned at a number of sites in the MSV genome were not infectious but multimeric units containing partial duplications were equally as infectious as complete tandem dimeric clones. Inoculation of tandem dimeric units conjugated into different strains of Agrobacterium showed that both A. tumefaciens and A. rhizogenes were able to transfer DNA to maize and this ability was Ti (or Ri) plasmid-specific. Nopaline strains of A. tumefaciens and both agropine and mannopine A. rhizogenes strains efficiently transferred MSV DNA to maize. A number of strains were capable of MSV DNA transfer to other members of the Gramineae, providing information which may be essential for Agrobacterium-mediated transformation of monocotyledonous plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00017445
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  • 3
    Electronic Resource
    Electronic Resource
    Transformation of plant cells via Agrobacterium (1989)
    Springer
    Plant molecular biology 13 (1989), S. 327-336 
    Details
    ISSN: 1573-5028
    Keywords: Agrobacterium ; plant cell transformation ; plant tumor induction ; plant vector systems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00025321
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  • 4
    Electronic Resource
    Electronic Resource
    Induction and growth properties of carrot roots with different complements of Agrobacterium rhizogenes T-DNA (1989)
    Springer
    Plant molecular biology 13 (1989), S. 43-52 
    Details
    ISSN: 1573-5028
    Keywords: Agrobacterium ; hairy roots ; T-DNA ; geotropism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Single and multiple infections of carrot discs were carried out with Agrobacterium strains harbouring different segments of pRi1855 TL-DNA cloned in the binary vector Bin 19 and with a strain carrying the TR-DNA from the same Ri plasmid. Roots induced by the various co-inoculations were cultured and their growth patterns were followed. Abundant roots could be induced by TL-DNA rol genes A, B and C as a single insert (rolA+B+C) and by rolB alone provided an extended segment beyond its 5′ noncoding region was included in the construction. A depression of rooting capability was caused by the inclusion of rolC together with rolB (rolB+C). In all cases co-inoculation with the Agrobacterium carrying TR-DNA-borne auxin genes was necessary for root induction since none of the rol constructions was in itself capable of eliciting any response; an exceeding majority of these roots were however shown to contain rol genes but no TR-DNA. Rooting was also elicited if rol constructions were co-inoculated with a strain carrying TL-DNA genes 13 and 14 (ORF13+14) instead of the TR-DNA strain. These roots were shown to contain both rol genes and ORF13+14. Striking differences in growth properties were shown by roots containing different complements of TL-DNA genes. Typical hairy root traits, high growth rate, branching and, most noticeably, absence of geotropism, were shown by roots containing rolB alone, while roots with rolA+B+C were geotropic as normal carrot roots. Hairy root traits were conferred to rolA+B+C roots by the concomitant presence of ORF13+14 and by the addition of auxin to the culture medium. A model is presented which attempts to rationalize the growth patterns by assigning interplaying roles to the various TL-DNA genes involved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00027334
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  • 5
    Electronic Resource
    Electronic Resource
    Phleomycin resistance as a dominant selectable marker for plant cell transformation (1989)
    Springer
    Plant molecular biology 13 (1989), S. 365-373 
    Details
    ISSN: 1573-5028
    Keywords: Agrobacterium ; binary vectors ; bleomycin ; phleomycin ; selective markers ; tobacco
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Tobacco cells are sensitive to bleomycin and phleomycin. The Tn5 and the Streptoalloteichus hindustanus (Sh) bleomycin resistance (‘Ble’) genes conferring resistance to these antibiotics have each been inserted into two plant expression vectors. They are flanked by the nopaline synthase (nos) or the cauliflower mosaic virus (CaMV) 35S promoters on one side, and by the nos polyadenylation signal on the other. These four chimaeric genes were introduced into the binary transformation vector pGA 492, which were thereafter mobilized into Agrobacterium tumefaciens strain LBA 4404. The resulting strains were used to transform Nicotiana tabacum cv. Xanthi nc using the leaf disc transformation procedure. In all cases, phleomycin- and bleomycin-resistant tobacco plants were regenerated from transformed cells under selective conditions; however the highest frequency of rooted plants was obtained when transformation was carried out with the ‘Sh Ble’ gene under the control of the 35S promoter. Phleomycin resistance was stably transmitted to sexual offspring as a dominant nuclear trait as confirmed by Southern blotting.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00015548
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  • 6
    Electronic Resource
    Electronic Resource
    Thiophene accumulation in relation to morphology in roots of Tagetes patula (1989)
    Springer
    Planta 179 (1989), S. 43-50 
    Details
    ISSN: 1432-2048
    Keywords: Agrobacterium ; Auxin and thiophene in roots ; Root culture ; Root morphology ; Tagetes ; Thiophene ; Transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Roots of marigold (Tagetes patula L.) accumulate thiophenes, heterocyclic sulfurous compounds with strong biocidal activity. In detached roots cultured in vitro, the thiophene content was 5 μmol·(g fresh weight)-1 which is 25-times higher than in roots attached to the plant. In roots derived from tissues transformed by Agrobacterium tumefaciens and A. rhizogenes, the morphology and thiophene content varied with the bacterial strain used. Transformation stimulated the elongation of the root tips and the formation of lateral roots but lowered the thiophene level to 20–50% relative to the concentration in untransformed detached roots. A negative correlation was found between the number of laterals in a root system and the thiophene content. Extensive branching and a decrease in thiophene accumulation was evoked in untransformed roots by indole-3-acetic acid (1–10 μmol·l-1) added to the medium. Within the roots, the highest thiophene concentrations were found in the tips. The results indicate that auxin directly or indirectly plays a role in the regulation of the thiophene level in root tips.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00395769
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  • 7
    Electronic Resource
    Electronic Resource
    Carrot (Daucus carota) hypocotyl transformation usingAgrobacterium tumefaciens (1989)
    Springer
    Plant cell reports 8 (1989), S. 354-357 
    Details
    ISSN: 1432-203X
    Keywords: Agrobacterium ; Somatic Embryogenesis ; Electroporation ; β-Glucuronidase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Daucus carota hypocotyl sections were transformed withAgrobacterium tumefaciens LBA4404 containing CaMV 35S promoter, β-glucuronidase coding sequence and the nopaline synthase (Nos) poly adenylation sequences in Bin 19. Sliced sterile seedling hypocotyl segments were preincubated for 2 days, co-cultivated withAgrobacterium for an additional 2 days, and then transferred to medium containing 100ug/ml of kanamycin and 400ug/ml carbenicillin. In 6 weeks kanamycin resistant calli were obtained in 5.8% of the explants from one variety. Calli were subcultured on solid medium, and in 4 weeks introduced into suspension culture. NPTII and Southern blot analysis confirmed that three selected lines were transformed with 1–3 copies of the GUSII construction. GUS activity in transformants was 5 to 250 fold over background.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00716672
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  • 8
    Electronic Resource
    Electronic Resource
    Upstream non-coding region which confers polar expression to Ri plasmid root inducing gene rolB (1989)
    Springer
    Molecular genetics and genomics 216 (1989), S. 239-244 
    Details
    ISSN: 1617-4623
    Keywords: Agrobacterium ; Hairy root ; T-DNA ; Glucuronidase gene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Root differentiation could be elicited on carrot discs by transformation with the agropine Ri plasmid rolB gene cloned in the binary vector Bin19, provided two conditions were met. Firstly, an adequate auxin supply had to be provided. This was achieved by co-inoculation with a strain carrying only the auxin synthetic genes of the TR-DNA. Most of the resulting roots were then shown to harbour only rolB and no aux genes. Secondly, an extended non-coding region (∼1200 bp) at the 5′ end of rolB had to be included in the construction. A shorter (∼300 bp) 5′ region, including TATA and CCAAT boxes, was not sufficient to trigger root differentiation. Both the extended (B1185) and reduced (B310) 5′ regions of rolB were then cloned upstream of the β-glucuronidase (GUS) reporter gene and infections carried out both on the apical and on the basal side of carrot discs. Strong expression of GUS, visualized histochemically as an intense blue colouring of transformed cells was observed with B1185-GUS constructions on the apical side of the discs. Only occasionally could coloured cells be observed on the basal side of the discs with B1185-GUS and on both apical and basal sides with B310-GUS constructions. Strong GUS expression was, on the contrary, achieved on cells of both auxin-rich (apical) and auxin-depleted (basal) sides of the discs with the strong constitutive viral promoter, CaMV35S. These results indicate the presence of an upstream regulatory region which confers polar expression to the rolB gene and suggest a role for auxin in its activation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00334362
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  • 9
    Electronic Resource
    Electronic Resource
    Transformation of meristematic cells in the shoot apex of cultured pea shoots byAgrobacterium tumefaciens andA. rhizogenes (1989)
    Springer
    Protoplasma 148 (1989), S. 101-105 
    Details
    ISSN: 1615-6102
    Keywords: In vitro shoots ; Pisum sativum ; Meristematic cells ; Shoot apices ; Transformation ; Agrobacterium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Different tissues in cultured pea shoots were inoculated withAgrobacterium tumefaciens wild types C 58 and ACH 5 andA. rhizogenes wild type 9402. The C 58 and 9402 bacteria induced the formation of tumours and hairy roots respectively while the ACH 5 was inactive. The younger the tissue the more rapidly it responded to the active bacteria. The shoot apex was the most reactive organ and developed into a tumour, theA. rhizogenes tumours subsequently giving rise to transformed hairy roots. Histological examination showed that transformed cells (including those within the apical dome) initially became highly vacuolate before dividing rapidly to form a tumour. These changes were accompanied by cell division in surrounding tissues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02079328
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  • 10
    Electronic Resource
    Electronic Resource
    Agrobacterium tumefaciens 6bgenes are strain-specific and affect the activity of auxin as well as cytokinin genes (1989)
    Springer
    Molecular genetics and genomics 219 (1989), S. 217-224 
    Details
    ISSN: 1617-4623
    Keywords: Agrobacterium ; 6b gene ; Agrobacterium host range ; Oncogenes ; Plant growth regulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The T-region located 6b gene of Agrobacterium tumefaciens has been found to interfere with cytokinin effects produced by the cotransferred ipt gene. We have compared the biological activity of three different 6b genes: A-6b from Ach5 (octopine, biotype 1), C-6b from C58 (nopaline, biotype 1) and T-6b from Tm4 (octopine, biotype III) by using different biological assays. Each 6b gene was inserted into a disarmed vector and tested on tobacco stems in coinfection experiments with the Ach5 cytokinin (ipt) gene (A-ipt). A-ipt/C-6b coinfections produced tumours with shoots, A-ipt/A-6b coinfections green tumours and A-ipt/T-6b coinfections tumours with a necrotic surface. The tumour phenotypes obtained were independent of the 6b/A-ipt coinfection ratios, indicating that the strain-specific 6b effects result from the activity of a non-diffusible 6b encoded product. Studies with ipt-less Tm4 mutants showed that 6b genes affect other tumour genes besides the ipt gene and pointed to an influence of T-6b on auxin effects resulting from the Tm4 iaa system. T-iaa/T-6b coinfection experiments showed that T-6b did indeed strongly increase tumour formation by the Tm4 iaa genes. The three 6b genes also have effects which do not require other T-region genes. The complex role of the 6b gene in crown gall induction and Agrobacterium host range will be discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00261180
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  • 11
    Electronic Resource
    Electronic Resource
    Single-stranded DNA transforms plant protoplasts (1989)
    Springer
    Molecular genetics and genomics 220 (1989), S. 65-68 
    Details
    ISSN: 1617-4623
    Keywords: Transformation ; Single-stranded DNA ; Agrobacterium ; Transient expression ; Extrachromosomal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The transfer of the Agrobacterium T-DNA to plant cells involves the induction of the Ti plasmid virulence genes. This induction results in the generation of linear single-stranded (ss) copies of the T-DNA inside Agrobacterium and such molecules might be directly transferred to the plant cell. A central requirement of this ss transfer model is that the plant cell must generate a second strand and integrate the resulting double-stranded (ds) molecule into its genome. Here we report that incubating plant protoplasts with ss or ds DNA under conditions favouring DNA uptake results in transformation. The frequencies of transformation are similar and analysis of ss transformants suggests that the introduced DNA becomes double stranded and integrated. Analysis of transient expression from introduced ss DNA suggests that generation of the second strand is rapid and extrachromosomal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00260857
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  • 12
    Electronic Resource
    Electronic Resource
    Distribution of two Agrobacterium tumefaciens insertion elements in natural isolates: Evidence for stable association between Ti plasmids and their bacterial hosts (1989)
    Springer
    Molecular genetics and genomics 219 (1989), S. 145-152 
    Details
    ISSN: 1617-4623
    Keywords: Agrobacterium ; IS elements ; Ti plasmid ; T-region ; Bacterial evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A large number of Agrobacterium tumefaciens strains of the biotype III group carry two to ten copies of two related IS elements, IS866 and IS867. A study of the distribution and localization of these elements in 54 strains showed that one IS866 and two IS867 copies are always found at characteristic sites on the octopine/cucumopine and vitopine Ti plasmids, whereas varying amounts of IS866 and IS867 copies occur at different positions on the chromosome. By comparison of the IS patterns, an evolutionary tree could be deduced which shows the phylogenetic relationships between 23 different types of Agrobacterium strains. The structures of the T-regions of the different strains were also compared. Within the octopine/cucumopine group, eight T-region patterns could be defined. These patterns were found to be correlated with the chromosomal IS patterns. This strongly suggests that the IS866 and IS867 containing Ti plasmids are stably associated with their bacterial hosts. The possible role of the IS866 and IS867 elements in Ti plasmid evolution is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00261170
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  • 13
    Electronic Resource
    Electronic Resource
    Agrobacterium-mediated transformation of somatic embryos as a method for the production of transgenic plants (1989)
    Springer
    Methods in cell science 12 (1989), S. 145-150 
    Details
    ISSN: 1573-0603
    Keywords: Agrobacterium ; gene transfer ; somatic embryos ; walnut ; β-glucuronidase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Somatic embryos have been successfully used as a target tissue for transformation and regeneration of transgenic walnut plants. Walnut somatic embryos, initiated originally from developing zygotic embryos, proliferate numerous secondary embryos from single cells in the epidermal layer. These single cells in intact somatic embryos are susceptible to transformation by genetically engineeredAgrobacterium tumefaciens and provide a means to regenerate nonchimeric transgenic plants. This gene transfer system has been made more efficient using, a) vector plasmids containing two marker genes encoding β-glucuronidase (GUS) and aminoglycoside phosphotransferase (APH(3′)II) and B) a more virulent strain ofAgrobacterium. This system should be applicable to any crop that undergoes repetitive embryogenesis from singleAgrobacterium-susceptible cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01404441
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  • 14
    Electronic Resource
    Electronic Resource
    Mass-spectrometric quantitation of cytokinins in tobacco crown-gall tumours induced by mutated octopine Ti plasmids of Agrobacterium tumefaciens (1988)
    Springer
    Planta 176 (1988), S. 230-234 
    Details
    ISSN: 1432-2048
    Keywords: Agrobacterium ; Auxin in tumors ; Cytokinin (in tumors, turnover, oxidase) ; Mutant (T-DNA) ; Nicotiana (crown gall) ; T-DNA mutants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The levels of the major cytokinins, zeatin, zeatin riboside, zeatin riboside-5′-monophosphate and zeatin-7-glucoside were measured in tobacco (Nicotiana tabacum L.) crown-gall tissues carrying insertion and deletion mutations in the T-DNA. Measurements were made by combined gas chromatography-mass spectrometry using selected ion monitoring with 15N- and 2H-labelled internal standards. The results demonstrate that, relative to wild-type tumour tissue, cytokinin levels are considerably elevated in tissues lacking functional T-DNA auxin-biosynthetic genes. From a detailed analysis of the major cytokinin metabolites it is concluded that a reduction in the extent of cytokinin degradation via N6-side-chain cleavage is an important factor leading to increased cytokinin levels in these tissues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00392449
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  • 15
    Electronic Resource
    Electronic Resource
    Tissue-specific expression of a pea legumin gene in seeds of Nicotiana plumbaginifolia (1988)
    Springer
    Plant molecular biology 10 (1988), S. 203-214 
    Details
    ISSN: 1573-5028
    Keywords: Agrobacterium ; gene expression ; legumin (Pisum) ; Nicotiana ; seed storage protein ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A 3.4-kilobase genomic DNA fragment from Pisum sativum L. containing the LegA gene, which encodes a major legumin storage protein, was transferred to Nicotiana plumbaginifolia using an Agrobacterium tumefaciens strain containing the Bin 19 binary vector system. Northern hybridisation analysis of legA-transformed plants demonstrated that legumin-specific RNA was present in developing seeds but not in developing leaves. Legumin protein was immunologically detected in the mature seeds of legA-transformed plants, and was present as the correct-size protein composed of disulphide-bonded polypeptides. It is concluded that the transferred pea genomic fragment contains all the information necessary for seed-specific expression of the legA gene, and for correct processing of the primary transcript and the precursor legumin protein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00027397
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  • 16
    Electronic Resource
    Electronic Resource
    Agrobacterium-mediated inoculation of plants with tomato golden mosaic virus DNAs (1988)
    Springer
    Plant molecular biology 10 (1988), S. 225-234 
    Details
    ISSN: 1573-5028
    Keywords: geminivirus ; Agrobacterium ; tomato golden mosaic virus ; agroinoculation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have adapted the “agroinfection” procedure of Grimsley and co-workers [4,5] to develop a simple, efficient, reproducible infectivity assay for the insect-transmitted, split-genome geminivirus, tomato golden mosaic virus (TGMV). Agrobacterium T-DNA vectors provide efficient delivery of both components of TGMV when used in mixed inoculation of wild-type host plants. A greater increase in infection efficiency can be obtained by Agrobacterium delivery of the TGMV A component to “permissive” transgenic plants. These “permissive” plants contain multiple tandem copies of the B component integrated into the host genome. An inoculum containing as few as 2000 Agrobacterium cells can produce 100% infection under these conditions. Further, our results show that there is a marked effect of the configuration of the TGMV A components within the T-DNA vector on time of symptom development. We have also found that transgenic plants carrying tandem copies of the A component do not complement the B component. Possible mechanisms to explain these results and the potential use of this system to further study the functions of the geminivirus components in infection are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00027399
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  • 17
    Electronic Resource
    Electronic Resource
    Enhanced nodule initiation on alfalfa by wild-typeRhizobium meliloti co-inoculated withnod gene mutants and other bacteria (1988)
    Springer
    Planta 174 (1988), S. 385-395 
    Details
    ISSN: 1432-2048
    Keywords: Agrobacterium ; Co-inoculation ; Medicago ; Mutant (Rhizobium) ; Nodulation ; Rhizobium ; Root nodule initiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Nodule formation on alfalfa (Medicago sativa L.) roots was determined at different inoculum dosages for wild-typeRhizobium meliloti strain RCR2011 and for various mutant derivatives with altered nodulation behavior. The number of nodules formed on the whole length of the primary roots was essentially constant regardless of initial inoculum dosage or subsequent bacterial multiplication, indicative of homeostatic regulation of total nodule number. In contrast, the number of nodules formed in just the initially susceptible region of these roots was sigmoidally dependent on the number of wild-type bacteria added, increasing rapidly at dosages above 5·103 bacteria/plant. This behavior indicates the possible existence of a threshold barrier to nodule initiation in the host which the bacteria must overcome. When low dosages of the parent (103 cells/plant) were co-inoculated with 106 cells/plant of mutants lacking functionalnodA, nodC, nodE, nodF ornodH genes, nodule initiation was increased 10- to 30-fold. Analysis of nodule occupancy indicated that these mutants were able to help the parent (wild-type) strain initiate nodules without themselves occupying the nodules. Co-inoculation withR. trifolii orAgrobacterium tumefaciens cured of its Ti plasmid also markedly stimulated nodule initiation by theR. meliloti parent strain. Introduction of a segment of the symbiotic megaplasmid fromR. meliloti intoA. tumefaciens abolished this stimulation.Bradyrhizobium japonicum and a chromosomal Tn5 nod- mutant ofR. meliloti did not significantly stimulate nodule initiation when co-inoculated with wild-typeR. meliloti. These results indicate that certainnod gene mutants and members of theRhizobiaceae may produce extracellular “signals” that supplement the ability of wild-typeR. meliloti cells to induce crucial responses in the host.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00959525
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  • 18
    Electronic Resource
    Electronic Resource
    Genotype-independent leaf disc transformation of potato (Solanum tuberosum) using Agrobacterium tumefaciens (1988)
    Springer
    Theoretical and applied genetics 76 (1988), S. 767-774 
    Details
    ISSN: 1432-2242
    Keywords: Solanum tuberosum ; Transformation ; Agrobacterium ; Ethylene ; Phosphinotricin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Leaves of the in vitro grown potato cultivars ‘Bintje’, ‘Berolina’, ‘Desiree’, and ‘Russet Burbank’ were wounded and co-cultivated with Agrobacterium strains having chimeric bar and nptII genes on a disarmed T-DNA. Each leaf from these cultivars formed numerous calli on kanamycin-containing medium, and almost all calli regenerated shoots. For ‘Russet Burbank’, it was necessary to include AgNO3 in the medium to obtain efficient shoot regeneration. The transformed plants have one to a few copies of the T-DNA, show NPT-II and PAT activities, and are resistant to high doses of the commercial preparation of phospinotricin (glufosinate). Almost no somaclonal variation was detected in trans-genic plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00303524
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  • 19
    Electronic Resource
    Electronic Resource
    Expression of bacterial chitinase protein in tobacco leaves using two photosynthetic gene promoters (1988)
    Springer
    Molecular genetics and genomics 212 (1988), S. 536-542 
    Details
    ISSN: 1617-4623
    Keywords: Agrobacterium ; Small subunit of ribulose bisphosphate carboxylase ; Chlorophyll a/b binding protein ; Promoter comparisons ; Chitinase activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A bacterial chitinase gene from Serratia marcescens (chiA) was fused to (i) a promoter of the ribulose bisphosphate carboxylase small subunit (rbcS) gene and (ii) two different chlorophyll a/b binding protein (cab) gene promoters from petunia. The resulting constructions were introduced into Agrobacterium Ti plasmid-based plant cell transformation vectors and used to generate multiple independent transgenic tobacco plants. ChiA mRNA and protein levels were measured in these plants. On average, the rbcS/chiA fusion gave rise to threefold more chiA mRNA than either cab/chiA fusion. We investigated the influence of sequences around the translational initiation ATG codon on the level of ChiA protein. The rbcS/chiA and cab/chiA fusions in which the sequence in the vicinity of the translational initiation codon is ACC ATGGC gave rise to transformants with higher levels of ChiA protein than those carrying a cab/chiA fusion with the sequence CAT ATGCG in the same region. This difference in translational efficiency is consistent with previous findings on preferred sequences in this region of the mRNA. In those transformants showing the highest level of ChiA expression, ChiA protein accumulated to about 0.25% of total soluble leaf protein. These plants contained significantly higher chitinase enzymatic activity than control plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00330861
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  • 20
    Electronic Resource
    Electronic Resource
    Relative strengths of the 35S califlower mosaic virus, 1′, 2′, and nopaline synthase promoters in transformed tobacco sugarbeet and oilseed rape callus tissue (1988)
    Springer
    Molecular genetics and genomics 212 (1988), S. 182-190 
    Details
    ISSN: 1617-4623
    Keywords: Promoter strength ; Transformed callus ; Chitinase gene ; Octopine synthase gene ; Agrobacterium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The 35S promoter of cauliflower mosaic virus and promoters from the nopaline synthase, 1′ and 2′ genes of Agrobacterium tumefaciens T-DNA were fused to the bacterial octopine synthase and chitinase gene coding regions. These chimaeric gene constructions were introduced into tobacco, sugarbeet and oilseed rape cells and their relative levels of expression measured by primer extension analysis of RNA isolated from pooled populations of stably transformed calli. In tobacco callus, the 35S promoter provided the highest levels of gene expression, followed by the 2′, 1′ and nopaline synthase promoters. While the ranking of these promoters is conserved in sugarbeet and oilseed rape callus, there is between-species variation in the relative strength of these promoters. In all three species, transcription initiation is conserved for each of the chimaeric gene constructions. Additional constructions in which the 5′ untranslated leader of a petunia chlorophyll a/b binding protein gene is substituted for DNA downstream of the 35S transcription start site demonstrates that heterologous 5′ leader sequences can be utilized to augment steady-state levels of reporter gene expression
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00322463
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  • 21
    Electronic Resource
    Electronic Resource
    Construction of a Tra− deletion mutant of pAgK84 to safeguard the biological control of crown gall (1988)
    Springer
    Molecular genetics and genomics 212 (1988), S. 207-214 
    Details
    ISSN: 1617-4623
    Keywords: Agrobacterium ; Crown gall ; Biological control ; Agrocin 84 ; Agrocin plasmid transfer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Agrobacterium radiobacter strain K84 is used commercially for the biological control of crown gall. It contains the conjugative plasmid pAgK84, which encodes the synthesis of agrocin 84, an antibiotic that inhibits many pathogenic agrobacteria. A breakdown of control is threatened by the transfer of pAgK84 to pathogens, which then become resistant to agrocin 84. A mutant of pAgK84 with a 5.9-kb deletion overlapping the transfer (Tra) region was constructed using recombinant DNA techniques. The BamHI fragment B1 which covers most of the Tra region was cloned in pBR325 and its internal EcoRI fragments D1 and H, which overlap the Tra region, were removed, leaving 3.7 kb and 0.5 kb of pAgK84 on either side of the deletion. The latter was increased to 3.3 kb by adding EcoRI fragment D2 from a BamHI fragment C clone. The modified pBR325 clone was mobilized into Agrobacterium strain NT1 harbouring pAgK84 with a Tn5 insertion just outside the Tra region but covered by the deletion. A Tra+ cointegrate was formed between the Tn5-insertion derivative and the pBR325-based deletion construct by homologous recombination. The cointegrate was transferred by conjugation to a derivative of strain K84 lacking pAgK84, in which a second recombination event generated a stable deletion-mutant by deletion-marker exchange. The resultant new strain of A. radiobacter, designated K1026, shows normal agrocin 84 production. Mating experiments show that the mutant plasmid, designated pAgK1026, is incapable of conjugal transfer at a detectable frequency.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00334686
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  • 22
    Electronic Resource
    Electronic Resource
    Rhizobium phaseoli: A molecular genetics view (1988)
    Springer
    Plant and soil 108 (1988), S. 179-184 
    Details
    ISSN: 1573-5036
    Keywords: Agrobacterium ; genomic rearrangements ; molecular genetics ; Rhizobium ; strains instability ; symbiosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract We have used molecular genetics techniques to analyze the structural and functional organization of genetic information ofRhizobium phaseoli, the symbiont of the common bean plantPhaseolus vulgaris. As in otherRhizobium species, the genome consists of the chromosome and plasmids of high molecular weight. Symbiotic determinants, nitrogen fixation genes as well as nodulation genes, are localized on a single replicon, the symbiotic (sym) plasmid. Thesym plasmid of differentR. phaseoli strains was transferred to anAgrobacterium tumefaciens strain cured of its native plasmids. In all cases, Agrobacterium transconjugants able to nodulate bean plants were obtained. Some of the transconjugants had the capacity to elicit an effective symbiosis. The genome ofR. phaseoli is complex, containing a large amount of reiterated DNA sequences. In mostR. pahseoli strains one of such reiterated DNA families corresponds to the nitrogenase structural genes (nif genes). A functional analysis of these genes suggested that the presence of reiteratednif genesis is related to the capacity of fixing atmospheric nitrogen in the symbiotic state. The presence of several repeated sequences in the genome might provide sites for recombination, resulting in genomic rearrangements. By analyzing direct descendants of a single cell in the laboratory, evidence of frequent genomic rearrangements inR. phaseoli was found. We propose that genomic rearrangements constitute the molecular basis of the frequent variability and loss of symbiotic properties in different Rhizobium strains.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02370113
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  • 23
    Electronic Resource
    Electronic Resource
    Structure, organization and expression of transferred DNA in Nicotiana plumbaginifolia crown-gall tissues (1987)
    Springer
    Planta 171 (1987), S. 393-405 
    Details
    ISSN: 1432-2048
    Keywords: Agrobacterium ; Crown-gall ; DNA, transferred ; Nicotiana (T-DNA) ; T-DNA structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Data are provided which show that transferred DNA (T-DNA) present in Nicotiana plumbaginifolia crown-gall lines in most cases was scrambled and not intact. Both wild-type, and ‘rooter’- and ‘shooter’-type mutants of octopine-type Agrobacterium tumefaciens were used to infect N. plumbaginifolia plantlets, cultured in vitro. Resulting tumors were excised from the plantlets and cultured for more than three years. During subculturing the tumor lines were scored for the following phenotypic traits: phytohormone autonomous growth in vitro (Aut+), spontaneous shoot regeneration (Reg+), root deficiency of shoots (Rod+), octopine production (Ocs+) and mannopine and agropine production (Mas+Ags+). An unexpectedly large variety of phenotypes was observed. For instance, two out of three tumor lines induced on haploid plantlets by the rooter mutant LBA4210 regenerated shoots, a phenomenon which is not observed for octopine tobacco tumor lines. Fifty percent of the crown-gall lines studied did not contain octopine. Only one line out of six independent lines analyzed was found to have a ‘regular’ T-DNA structure. Occurrence of aberrant T-DNA structures was not correlated with the ploidy level of infected plantlets, nor with the T-region structure of the inciting bacterial strain. The pattern of TL-DNA transcripts was studied for one line and correlated well with the aberrant T-DNA structure detected. Segments of TR-DNA, having irregular structures as well, were detected in two out of the six lines studied. The scrambled nature of the TR-DNA explained the absence of mannopine and agropine in these two lines. In addition, it was observed that N. plumbaginifolia tissue lines which did not carry T-DNA, became readily phytohormone autotrophic (habituated) at an early stage in tissue culture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00398685
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  • 24
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    Electronic Resource
    Stability and expression of transferred DNA in F1 tobacco transformants studied at various states of differentiation (1987)
    Springer
    Planta 172 (1987), S. 448-462 
    Details
    ISSN: 1432-2048
    Keywords: Agrobacterium ; Crown gall ; Nicotiana (crown gall, T-DNA) ; Transformation (tobacco) ; Transferred DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Grafts from the SR1 tobacco crown-gall lines NT1 (having a deletion eliminating part of the transferred (TL)-DNA auxin locus) and NT2 (having an IS60 insertion in gene 2 of this auxin locus) were cross-pollinated with pollen from nontransformed SR1 tobacco plants. One half of the resulting F1 progeny resembled the female parent (“transformed” NT1-like and NT2-like seedlings respectively) and one half resembled the male parent (“non-transformed” SR1-like seedlings). For three states of differentiation (callus, shoot, graft) all phenotypic markers of the transformed seedlings studied were identical to those of the transformed female parent. Most phenotypic markers of non-transformed seedlings corresponded with markers of the male parent. Unlike the SR1 male parent, however, the SR1-like seedlings showed the maternal traits hyperstyly and male sterility. These two traits were inherited by 100% of the F1 seedlings studied. Ninety percent of the non-transformed F2 seedlings were still male-sterile whereas in as much as 50–100% of the non-transformed F3 progeny, male fertility had been restored. The SR1-like F1 seedlings did not contain any T-DNA. At the level of restriction-fragment analysis the T-DNA structures of all 22 NT1-like seedlings examined were identical to the T-DNA structure of their female parent NT1. The steady-state level of transcripts 4 (cytokinin locus) and 6a/6b relative to transcript 3 (octopine-synthase locus) was less in shoots and grafts than in callus. Observed variation in shoot morphology among the twenty-two NT1-like seedlings was not correlated with T-DNA structure, organization and expression at the level of steady-state mRNA. The T-DNA structure of NT2 and its transformed seedlings deviated from regular border-to-border TL-DNA, in that it extended beyond the left border repeat.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00393860
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  • 25
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    Electronic Resource
    Initiation of auxin autonomy in Nicotiana glutinosa cells by the cytokinin-biosynthesis gene from Agrobacterium tumefaciens (1987)
    Springer
    Planta 171 (1987), S. 539-548 
    Details
    ISSN: 1432-2048
    Keywords: Agrobacterium ; Cytokinin biosynthesis ; Auxin autonomy ; Nicotiana (auxin autonomy) ; Tumor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Agrobacteria carrying mutations at the auxin-biosynthesizing loci (iaaH and iaaM of the Ti plasmid) induce shoot-forming tumors on many plant species. In some cases, e.g. Nicotiana glutinosa L., tumors induced by such mutant strains exhibit an unorganized and fully autonomous phenotype. These characteristics are stable in culture at both the tissue and cellular level. We demonstrate that the cytokinin-biosynthesis gene (ipt) of the Ti plasmid is responsble for the induction of both auxin and cytokinin autonomy in N. glutinosa. Cloned cell lines carrying an ipt gene but lacking iaaH and iaaM are capable of accumulating indole-3-acetic acid. Interestingly, non-transformed N. glutinosa tissues exhibit an auxin-requiring phenotype when they are grown on medium supplemented with an exogenous supply of cytokinin. These results strongly indicate that exogenously supplied cytokinin does not mimic all the effects of the expression of the ipt gene in causing the auxin-autonomous growth of N. glutinosa cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00392304
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  • 26
    Electronic Resource
    Electronic Resource
    The Pseudomonas savastanoi tryptophan-2-mono-oxygenase is biologically active in Nicotiana tabacum (1987)
    Springer
    Planta 172 (1987), S. 555-562 
    Details
    ISSN: 1432-2048
    Keywords: Agrobacterium ; Auxin biosynthesis ; Indole-3-acetamide ; Pseudomonas ; Tryptophan-2-mono-oxygenase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract It has been proposed that the “eukaryotic” T-DNA-encoded indole-3-acetic acid (IAA) biosynthesis genes of Agrobacterium tumefaciens and their prokaryotic counterpart in Pseudomonas savastanoi originated from common ancestor genes. This paper provides additional evidence for the functional similarity between the gene products. We have demonstrated that a chimeric gene consisting of the coding sequence of the P. savastanoi tryptophan-2-mono-oxygenase (iaaM gene) and a plant promoter encodes an active enzyme in Nicotiana tabacum. Transformants obtained with this chimeric gene grew as a callus on hormone-free media. No stably transformed plantlets could be isolated. The callus tissues contained extremely high levels of indole-3-acetamide and slightly elevated levels of IAA. Either indole-3-acetamide by itself has a low auxin activity or, alternatively, it is converted aspecifically and at low rates into IAA. The P. savastanoi tryptophan-2-mono-oxygenase activity in plants is also able to detoxify the amino-acid analogue 5-methyltryptophan. This property can be used for positive selection of transformed calli.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00393874
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  • 27
    Electronic Resource
    Electronic Resource
    Two Agrobacterium tumefaciens genes for cytokinin biosynthesis: Ti plasmid-coded isopentenyltransferases adapted for function in prokaryotic or eukaryotic cells (1987)
    Springer
    Molecular genetics and genomics 210 (1987), S. 156-164 
    Details
    ISSN: 1617-4623
    Keywords: Agrobacterium ; Ti plasmids ; Cytokinin biosynthesis ; Isopentenyltransferase ; trans-zeatin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Tzs and ipt are two Ti plasmid genes coding for proteins with isopentenyltransferase (IPT) activity in vitro. We cloned both genes for protein expression in Escherichia coli and in Agrobacterium tumefaciens, and we investigated differences between the two genes by analysing the properties of the proteins in vitro and in vivo. In vitro, extracts with tzs or ipt-coded proteins had high IPT activity, and the enzymes were identical in most properties. The most important difference was detected in vivo: the tzs-encoded protein was very active in cytokinin production, while the ipt protein required overexpression in order to obtain measurable activity in bacteria. In both cases, rans-zeatin was the major product of the gene activity. Formation of this cytokinin requires a hydroxylase function in addition to the IPT reaction. No such activity could be ascribed to tzs or ipt-encoded proteins in vitro or in vivo, but cytokinin hydroxylase activity was detected in cells and extracts of E. coli, regardless of the presence or absence of the cytokinin genes. Based on these results it is proposed that both genes code for a single enzyme activity (isopentenyltransferase), that the genes and proteins are adapted for function either in bacteria (tzs) or in transformed plant cells (ipt), and that in both prokaryotic and eukaryotic cells hydroxylation to trans-zeatin is a function contributed by host enzymes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00337773
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  • 28
    Electronic Resource
    Electronic Resource
    Sequence context of the T-DNA border repeat element determines its relative activity during T-DNA transfer to plant cells (1987)
    Springer
    Molecular genetics and genomics 210 (1987), S. 338-346 
    Details
    ISSN: 1617-4623
    Keywords: Agrobacterium ; Ti plasmid ; T-DNA borders ; T-DNA transfer activity ; Plant cell transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We present a detailed analysis of the function of the right and left T-DNA border regions of the nopaline Ti plasmid of Agrobacterium tumefaciens. An avirulent deletion of the right border of the nopaline Ti plasmid (pGV3852) was used as an acceptor for 14 different T-DNA border constructs. The functional activities of these constructs were assayed by their ability to restore virulence, i.e. transformation on inoculated plants. Tumorigenicities were measured in several independent experiments over a 2 year period and the statistical significance of their relative levels was evaluated. The data indicate: (i) the entire sequence of the 25 bp direct repeat of the T-DNA is required to provide an efficient substrate for mediating T-DNA transfer events; deletion derivatives of either the conserved or the vaiable domain of the repeat are defective in T-DNA transfer; (ii) while the 25 bp direct repeat alone can promote the T-DNA transfer, the flanking sequences of the repeats enhance (on the right) or attenuate (on the left) their activity; and (iii) tumorigenicity measurements vary depending on the plant assay system: potato discs are more sensitive than wounded tobacco leaves in detecting differences in T-DNA border activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00325703
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  • 29
    Electronic Resource
    Electronic Resource
    High meiotic stability of a foreign gene introduced into tobacco by Agrobacterium-mediated transformation (1987)
    Springer
    Molecular genetics and genomics 207 (1987), S. 171-175 
    Details
    ISSN: 1617-4623
    Keywords: Nicotiana tabacum ; Agrobacterium ; Plant transformation ; Genetic stability ; Kanamycin resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two lines of transgenic Nicotiana tabacum transformed to kanamycin resistance by means of a binary Agrobacterium vector containing a nos-npt gene were investigated over three generations. Southern hybridization and crossing analyses revealed that a single copy of T-DNA had integrated in each line and that the kanamycin resistance was regularly transmitted to the progeny as a monogenic dominant trait. Homozygous transgenic plants were fully fertile, morphologically normal and did not significantly differ from wild-type plants in the quantitative characters examined (plant height, flowering time). The two lines showed very low, but significantly different levels of meiotic instability: kanamycin-sensitive plants occurred among backcross progeny from homozygous transgenic plants with frequencies of 6/45,000 and 25/45,000, respectively. The sensitive plants arose independently of each other and thus resulted from meiotic rather than mitotic events. These findings demonstrate for the first time that integrated foreign genes can be transmitted to progeny with the high degree of meiotic stability required for commercial varieties of crop plants. They emphasize the importance of non-homologous integration and of avoiding co-integration of inactive gene copies for achieving meiotically stable transformants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00331506
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  • 30
    Electronic Resource
    Electronic Resource
    Agrobacterium rhizogenes T-DNA genes capable of inducing hairy root phenotype (1987)
    Springer
    Molecular genetics and genomics 209 (1987), S. 475-480 
    Details
    ISSN: 1617-4623
    Keywords: Agrobacterium ; Hairy root ; T-DNA ; Transgenic tobacco
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Segments of the TL-DNA of the agropine type Ri plasmid pRi 1855 encompassing single and groups of open-reading frames were cloned in the Ti plasmid-derived binary vector system Bin 19. Leaf disc infections on Nicotiana tabacum led to transformed plants, some of which showed typical hairy root phenotypes, such as the wrinkled leaf morphology, excessive and partially non geotropic root systems and the ability of leaf explants to differentiate roots in a hormone-free culture medium. Particularly interestingly, most of these traits were shown by plants transformed with a TL-DNA segment encompassing the single ORF 11, corresponding to the rolB locus. Hairy root can be induced by this latter T-DNA segment on wounded stems of tobacco plants; hairy root induction on carrot discs requires, on the contrary, a more complex complement of TL-DNA genes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00331152
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  • 31
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    Electronic Resource
    Characterization and sequence determination of the replicator region in the hairy-root-inducing plasmid pRiA 4b (1987)
    Springer
    Molecular genetics and genomics 206 (1987), S. 1-8 
    Details
    ISSN: 1617-4623
    Keywords: Ri plasmid ; Agrobacterium ; Mini replicon ; Replication origin ; Incompatibility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Starting from a cosmid library of the 250 kb hairy root inducing plasmid pRiA 4b, a mini-pRiA 4b replicon of 4.6 kb was isolated. This mini-plasmid was stably maintained in Agrobacterium species and its replication characteristics, such as temperature-sensitive replication, copy number and incompatibility, were similar to those of the parental pRiA 4b. Analysis of deletion mutants indicated that almost the entire 4.6 kb region was required for autonomous replication. The nucleotide sequence of mini-pRiA 4b was determined by the chain-termination method. Three large open reading frames, which are likely to contribute to the replication of pRiA 4b, were identified in the same orientation along the sequence.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00326529
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  • 32
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    Electronic Resource
    Agrobacterium mediated transformation and regeneration of Populus (1987)
    Springer
    Molecular genetics and genomics 206 (1987), S. 192-199 
    Details
    ISSN: 1617-4623
    Keywords: Poplar ; Transformation ; Agrobacterium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A plant transformation and regeneration system has been developed for Populus species. Leaf explants, from stabilized shoot cultures of a Populus hybrid NC-5339 (Populus alba x grandidentata), were co-cultivated with Agrobacterium tumefaciens on a tobacco nurse culture. Both oncogenic and disarmed strains of A. tumefaciens harboring a binary vector which contained two neomycin phophotransferase II (NPT II′) and one bacterial 5-enolpyruvylshikimate 3-phosphate (EPSP) synthase (aroA) chimeric gene fusions were used. Shoots did not develop when leaf explants were co-cultivated with the binary disarmed strain of A. tumefaciens. However, transformed plants with and without the wild type T-DNA were obtained using an oncogenic binary strain of A. tumefaciens. Successful genetic transformation was confirmed by NPT II′ enzyme activity assays, Southern blot analysis and immunological detection of bacterial EPSP synthase by Western blotting. This is the first report of a successful recovery of transformed plants of a forest tree and also the first record of insertion and expression of a foreign gene of agronomic importance into a woody plant species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00333574
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  • 33
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    Absence in monocotyledonous plants of the diffusible plant factors inducing T-DNA circularization and vir gene expression in Agrobacterium (1987)
    Springer
    Molecular genetics and genomics 209 (1987), S. 221-226 
    Details
    ISSN: 1617-4623
    Keywords: Agrobacterium ; Monocotyledonous plants ; Plant factors ; T-DNA circularization ; vir gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary T-DNA circularization is one of the molecular events specifically induced in agrobacterial cells upon their infection of dicotyledonous plant cells. We developed a seedling co-cultivation procedure to determine whether or not monocotyledonous plants have the ability to induce T-DNA circularization and vir gene expression. Co-cultivation of Agrobacterium tumefaciens with seedlings of dicotyledonous plants showed that the circularization event takes place efficiently. The exudates and extracts of the seedlings also effectively induced T-DNA circularization and vir gene expression, indicating that dicotyledonous seedlings contain diffusible factors capable of inducing these molecular events. In contrast, neither T-DNA circularization nor vir gene expression was detectable when Agrobacterium was incubated with seedlings of monocotyledonous plants. Supplementing with acetosyringone, a known inducer of vir gene expression and T-DNA circularization, resulted in the induction of circularization during co-cultivation with monocotyledonous seedlings. These results indicate that the seedlings of monocotyledonous plants have no detectable amounts of diffusible inducers, unlike dicotyledonous seedlings. Therefore, it is unlikely that the vir genes are expressed in Agrobacterium inoculated in monocotyledonous plants. This may be one of the blocks in tumorigenesis of monocotyledonous plants by Agrobacterium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00329646
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  • 34
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    A plasmid sequence from Rhizobium leguminosarum 300 contains homology to sequences near the octopine TL-DNA right border (1987)
    Springer
    Molecular genetics and genomics 209 (1987), S. 580-584 
    Details
    ISSN: 1617-4623
    Keywords: Rhizobium ; Agrobacterium ; TDNA ; Insertion sequence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The DNA sequence from a Rhizobium leguminosarum 300 (RL300) plasmid that contains homology to the Tc-DNA of Agrobacterium tumefaciens is described. The RL300 sequence has 78% homology to a 359 bp sequence in the Tc-DNA of pTi15955. The RL300 homology starts approximately 100 bp from the 24 bp border sequence of the TL-DNA and ends approximately 3 bp from an IS66 homolog in the Tc-DNA. An unusual feature of the RL300 homology is the presence of 81 bp direct repeats with Tc-DNA homology, separated by 201 bp. One end of each direct repeat has a 12 bp palindrome. Four cloned sequences of RL300 with homology to the T DNA region were hybridized to plasmid lysates of RL300 derivatives to determine the source of each plasmid. The sequenced homolog, originally on pRH228, was isolated from pRL7JI; the other 3 homologs were isolated from the transmissable plasmids pRL7JI (pRH235) and pRL8JI (pRH235 and pRH236).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00331166
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  • 35
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    Strain and cultivar specificity in the Agrobacterium-soybean interaction (1987)
    Springer
    Plant cell, tissue and organ culture 8 (1987), S. 3-15 
    Details
    ISSN: 1573-5044
    Keywords: soybean ; plant transformation ; Agrobacterium ; Tiplasmid ; nopaline
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The response of Glycine max., G. soja and G. canescens genotypes to inoculation with different Agrobacterium strains was assessed. Percent visual tumor formation and tumor size varied widely among species and genotypes. Susceptible genotypes displayed a heightened response to nopaline strains of A. tumefaciens, relative to octopine, agropine, and A. rhizogenes strains. A nopaline strain engineered to contain a chimeric neomycin phosphotransferase II gene conferred kanamycin resistance to soybean tissue at kanamycine levels as high as 300 μg/ml.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00040728
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  • 36
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    Rhizobium nod genes are involved in the induction of two early nodulin genes in Vicia sativa root nodules (1987)
    Springer
    Plant molecular biology 9 (1987), S. 171-179 
    Details
    ISSN: 1573-5028
    Keywords: Agrobacterium ; nodulin gene expression ; Rhizobium ; root nodule ; sym-plasmid ; Vicia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Nodulin gene expresison was studied in Vicia sativa (common vetch) root nodules induced by several Rhizobium and Agrobacterium strains. An Agrobacterium transconjugant containing a R. leguminosarum symplasmid instead of its Ti-plasmid, that was previously shown to form “empty” nodules on pea, induced nodules on Vicia roots in which nodule cells were infected with bacteria. In the Vicia nodules induced by this transconjugant, two so-called early nodulin genes were found to be expressed, whereas in the nodules formed on pea the expression of only one early nodulin gene was detected. In both cases the majority of the nodulin genes was not expressed. Apparently, an intracellular location of the bacteria is not sufficient for the induction of the majority of the nodulin genes. All nodulin genes were expressed in nodules induced by cured Rhizobium strains containing cosmid clones that have a 10 kb nod region of the sym-plasmid in common. Since in tumours no nodulin gene expression was found at all, the Agrobacterium chromosome does not contribute to the induction of nodulin genes. Therefore it is concluded that the signal for the induction of the expression of the two Vicia early nodulin genes is encoded by the nod-region, and the signal involved in the induction of all other nodulin genes has to be located outside the sym-plasmid, on the Rhizobium chromosome. The apparent difference in early nodulin gene expression between pea and Vicia is discussed in the light of the usefulness of Agrobacterium transconjugants in the study of nodulin gene expression.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00015649
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  • 37
    Electronic Resource
    Electronic Resource
    The 5′ flanking DNA of a patatin gene directs tuber specific expression of a chimaeric gene in potato (1987)
    Springer
    Plant molecular biology 9 (1987), S. 345-375 
    Details
    ISSN: 1573-5028
    Keywords: Patatin ; Solanum tuberosum L. ; Agrobacterium ; chimaeric gene ; chloramphenicol acetyltransferase (CAT)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A member of the patatin multigene family which encodes the major soluble tuber protein was isolated from potato cultivar Désirée. Analysis by strategic nucleotide sequencing demonstrated close homology to analogous regions of previously isolated patatin genomic clones from different cultivars. A 3.8-kb fragment containing the promoter and 5′ flanking DNA of the patatin gene was used to construct a transcriptional fusion gene with the coding DNA of the bacterial chloramphenicol acetyltransferase (CAT) gene and the polyadenylation/termination sequences of the nopaline synthase gene (nos). The chimaeric gene was reintroduced into potato cultivar Désirée by agrobacterial transformation of tissue slices. Regenerated transformed plants showed expression of the chimaeric gene (as determined by CAT activity) in tubers, but not in leaves, stems or roots of in vitro grown plants. Independent transformants did not show substantial variation in the level of induced tuber-specific CAT activity. Thus, information contained within 3.8 kb of the 5′ flanking DNA of the patatin gene analysed is sufficient to direct tuber-specific expression, largely independent of position effects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00014911
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  • 38
    Electronic Resource
    Electronic Resource
    Neoplastic progression in crown gall in tobacco without elevated auxin levels (1986)
    Springer
    Planta 169 (1986), S. 454-461 
    Details
    ISSN: 1432-2048
    Keywords: Agrobacterium ; Auxin in tumor tissue ; Crown gall ; Nicotiana (cell transformation) ; Tumor morphology and progression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have isolated two stable variants from a crown-gall teratoma tissue of tobacco (Nicotiana tabacum L.) transformed by Agrobacterium tumefaciens strain A66, a mutant of the virulent A6 strain containing an insertion sequence in the tumor-inducing (Ti) plasmid at the locus coding for auxin biosynthesis. Normally tobacco cells transformed by strain A66 spontaneously form shoots in culture and will not grow on hormone-free medium unless shoots develop. The variant tissue lines, isolated from the teratoma tissue after prolonged culture in the dark, grew as friable and unorganized tissues on hormone-free growth medium. Growth of the variants was more sensitive to auxin feeding than growth of the parental teratoma line, and the auxin dose-response curves of the variant lines were similar to those obtained with A6-transformed tobacco cells. Southern blot analysis of DNA from the parental teratoma line and one of the variants showed no differences in copy number or organization of the oncogenic DNA sequence (T-DNA) transferred from the bacterium, indicating that the variant phenotype did not result from reversion of the A66 mutation. Radio-immunoassay analysis showed similar levels of indole-3-acetic acid (IAA) in the variants and parental teratoma line (3–50 and 38–42 pmol·(gFW)-1, respectively), whereas an A6-transformed cell line contained much higher IAA levels (150–1200 pmol·(g FW)-1). Low levels of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid in the variants and the parental teratoma line (〈5 nmol·(g FW)-1) as compared with that found in the A6-transformed line (〉100 nmol· (g FW)-1) provided additional, indirect evidence for low auxin levels in the variant lines. These results indicate that crown-gall teratoma tissues of tobacco may switch to the unorganized, auxin-sensitive phenotype without an increase in auxin content.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00392144
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  • 39
    Electronic Resource
    Electronic Resource
    TL-DNA from Agrobacterium rhizogenes plasmid pRi1855 reduces the osmotic pressure in transformed plants grown in vitro (1986)
    Springer
    Planta 168 (1986), S. 106-112 
    Details
    ISSN: 1432-2048
    Keywords: Agrobacterium ; Brassica (transformed plants) ; Genetic manipulation ; Osmotic pressure ; Potassium ; Solanum (transformed plants)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Growth, water content, osmotic pressure and solute content were examined for normal potato (Solanum tuberosum L. cv. Desiree) and a derivative (line D9X8a), which was genetically transformed with TL-DNA from Agrobacterium rhizogenes. Plants were grown (i) in vitro, (ii) in a growth chamber and (iii) in the field. In vitro, the transformed potato plants produced more biomass than the untransformed plants, partly because they had a higher water content. Potassium concentration and osmotic pressure were lower in cell sap extracted from the transformed potato shoots. In some cases the difference was as much as 50%. These differences were less clear, absent or reversed in plants from a growth chamber or from the field. In the field, however, transformed potato senesced early. It is suggested that a cellular basis for these observations may be changes induced by Ri TL-DNA expression products in plant membrane properties.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00407016
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  • 40
    Electronic Resource
    Electronic Resource
    Isozyme gene expression in potato tumors incited by Agrobacterium (1986)
    Springer
    Theoretical and applied genetics 72 (1986), S. 373-376 
    Details
    ISSN: 1432-2242
    Keywords: Crown gall tumors ; Hairy root disease ; Potato ; Isozyme gene expression ; Agrobacterium ; Solanum tuberosum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two plant tumors (crown galls and hairy roots) were experimentally provoked on potato cv. ‘Désirée’ by oncogenic strains of Agrobacterium tumefaciens and A. rhizogenes. A marked shift in the expression of some organ-specific genes occurred in crown galls derived from the central zone of tubers: two novel isozyme genes (Est-B and Pox-E) were expressed, two others (Est-C and Pox-F) were suppressed and the remaining ones were maintained in the original state. When the starting tissue was the stem segment, a smaller shift occurred, namely the activation of Adh-A and the suppression of Pox-F. In all cases, the isozyme profiles characterizing all crown galls, whatever their origin, were identical. Under normal aeration conditions, Adh-A was not expressed in either tumoral or non-tumoral roots. However, under the relative anaerobic conditions of in vitro cultures, a difference existed between both types of roots: Adh-A was expressed in normal but not in tumoral roots. This means that hairy roots can tolerate higher levels of anaerobiosis without giving rise to an anaerobic response. For the remaining isozymes, no alteration occurred in either organized (hairy root) or unorganized (crown gall) tumors, as compared to the corresponding non-tumoral tissues (normal root and callus, respectively).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00288575
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  • 41
    Electronic Resource
    Electronic Resource
    Multiple transformation of plant cells by Agrobacterium may be responsible for the complex organization of T-DNA in crown gall and hairy root (1986)
    Springer
    Molecular genetics and genomics 202 (1986), S. 388-393 
    Details
    ISSN: 1617-4623
    Keywords: Agrobacterium ; Ti plasmid ; Ri plasmid ; Opines ; T-DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Inoculation of carrot discs and Lotus corniculatus plantlets with mixtures of different Agrobacterium rhizogenes or of A. rhizogenes and A. tumefaciens or with Agrobacterium strains harboring both an Ri and a modified Ti plasmid resulted in frequent multiple (pluribacterial) transformation of cells, as revealed by the mixed opine-type of hairy roots arising from them. Multiple transformation may account for the presence of dispersed T-DNA inserts in crown gall and hairy root lines. A plant genetic engineering strategy based on segregation of T-DNA inserts in the progeny of multiple transformants is proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00333267
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  • 42
    Electronic Resource
    Electronic Resource
    Genetic studies on the role of octopine T-DNA border regions in crown gall tumor formation (1986)
    Springer
    Molecular genetics and genomics 202 (1986), S. 312-320 
    Details
    ISSN: 1617-4623
    Keywords: Agrobacterium ; Plant transformation ; T-DNA borders ; T-DNA transfer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Crown gall tumors result from transfer and integration of the T-DNA from the Ti plasmid of Agrobacterium tumefaciens into plant nuclear DNA. In the present study, recombinant plasmids containing deletion and rearrangement deriviatives of the T-DNA region of the octopine Ti plasmid pTiA6 were tested in a binary tumorigenesis system (Hoekema et al. 1983) to determine the requirements for T-DNA border regions in tumor formation. Since two defined segments of the T-DNA region of octopine Ti plasmids can be detected in tumor DNA (the left (TL-) and right (TR-) DNA), four border regions exist in this Ti plasmid. Agrobacteria harboring plasmid constructs which contain a T-DNA gene capable of inciting tumors (gene 4, the tmr gene, which is involved in cytokinin biosynthesis) and various T-DNA border regions were tested for ability to cause tumors on Nicotiana glauca and other host plants. Such tmr constructs containing as their only border region the right border of either the TL-DNA or the TR-DNA are fully tumorigenic. Analogous tmr constructs containing only the TL-DNa left border region are not tumorigenic. These results do not depend on the orientation or position of the single border with respect to the tmr gene; furthermore, the TR-DNA right border can confer tumor-forming ability despite the presence of an intervening copy of the TL-DNA left border. These results for relatively small plasmids are contrasted with previously determined requirements for border regions in tumorigenesis by intact Ti plasmids. A model previously proposed by Wang et al. (1984) for the role of border regions in DNA transfer to plant cells is extended in order to explain the tumor-forming ability of plasmid constructs containing a single border region. The results of this study interpreted according to the model suggest that the octopine TL-DNA left border is defective in this DNA-transfer process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00331657
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  • 43
    Electronic Resource
    Electronic Resource
    Characterisation of the T-region of the SAP-type Ti-plasmid pTiAT181: identification of a gene involved in SAP synthesis (1986)
    Springer
    Molecular genetics and genomics 202 (1986), S. 62-67 
    Details
    ISSN: 1617-4623
    Keywords: Agrobacterium ; Succinamopine ; T-DNA ; AT181
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The T-region of pTiAT181, a SAP(succinamopine)-type Ti-plasmid, is described and is found to be similar to that of the nopaline-type pTiT37. The two major differences are a deletion of 2.9 kb inside the left hand end of pTiAT181, and a right hand region comprised of DNA specific to pTiAT181. This novel DNA was shown by its transfer to plants using a binary vector, to encode an enzyme involved in the synthesis of SAP.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00330518
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  • 44
    Electronic Resource
    Electronic Resource
    Isolation and characterization of a light-inducible, organ-specific gene from potato and analysis of its expression after tagging and transfer into tobacco and potato shoots (1986)
    Springer
    Molecular genetics and genomics 205 (1986), S. 14-22 
    Details
    ISSN: 1617-4623
    Keywords: Agrobacterium ; Light induction ; Position effect ; Transformed plants ; Gene isolation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The isolation and analysis of several cDNAs and of one genomic clone encoding ST-LS1, a single-copy gene fromSolanum tuberosum with leaf/stem-specific, light-inducible expression, is described. The structure of the gene was determined by sequencing several overlapping partial cDNA clones as well as the genomic clone and by determining the transcription start site by RNA protection experiments. A “tagged” derivative of the gene, obtained by exon modification, was reintroduced into potato and into tobacco shoots usingAgrobacterium/Ti-plasmid vector systems. The modified gene was expressed in both tobacco and potato shoots giving rise to an RNA of approximately 1,200 nucleotides which exceeded the length of the RNA made from the endogenous gene by the expected size of the “tag” (470 nucleotides). The level of expression of the modified gene varied substantially between independent transformants. A high proportion of the transformants (20%–40%) synthesized as much RNA from the added gene as from the resident gene. Expression of the transferred gene was light induced. Qualitatively and quantitatively the expression of the introduced gene was similar in a homologous (potato) and in a heterologous, but related, cellular background (tobacco).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02428027
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  • 45
    Electronic Resource
    Electronic Resource
    A convenient autoradiographic technique for study of uptake of minerals by plant roots and the effects of environmental factors upon the process (1986)
    Springer
    Plant and soil 92 (1986), S. 299-302 
    Details
    ISSN: 1573-5036
    Keywords: Agrobacterium ; Iron uptáke ; Siderophore
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary An autoradiographic procedure for the investigation of the uptake of minerals by plant roots and its application to the stimulation of uptake of ferric iron by agrobactin is described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02372643
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  • 46
    Electronic Resource
    Electronic Resource
    The role of bacterial attachment in the transformation of cell-wall-regenerating tobacco protoplasts by Agrobacterium tumefaciens (1985)
    Springer
    Planta 166 (1985), S. 300-308 
    Details
    ISSN: 1432-2048
    Keywords: Agrobacterium ; Nicotiana (protoplast transformation) ; Protoplast (attachment) of Agrobacterium) ; Transformation (protoplasts)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The presence of a newly formed primary cell wall was shown to be required for attachment and subsequent transformation of tobacco leaf protoplasts by Agrobacterium tumefaciens in cocultivation experiments. In these experiments both protoplasts at different stages after their isolation and cell-wall inhibitors were used. The specificity of Agrobacterium attachment was shown by using other kinds of bacteria that did not attach. By diminishing the concentration of divalent cations using ethylenediaminetetraacetic acid, neither attachment nor transformation was found; however, when more specifically the Ca2+concentration was lowered by ethylene glycol-bis (β-aminoethyl ether)-N,N,N′,N′-tetraacetic acid, both phenomena occurred. Commercial lectins had no effect on binding, but this observation does not exclude the involvement of other lectins. Protoplasts isolated from various crown-gall callus tissues also developed binding sites, but when they were at the stage of dividing cells, attachment of agrobacteria was no longer observed. In this respect, cells from protoplasts of normal tobacco leaves behaved differently. Even 16 d after protoplast isolation, the dividing cells were still able to bind A. tumefaciens, while transformation was not detected. For transformation of 3-d-old tobacco protoplasts, a minimal co-cultivation period of 24 h was required, while optimal attachment took place within 5 h. It is concluded that the primary cell wall was sufficiently well formed that certain functional receptor molecules were available for attachment of Agrobacterium as the first step of a multistep process leading to the transformation of cells. The expression of bacterial functions required for attachment, moreover, was independent of the presence of Ti-plasmid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00401165
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  • 47
    Electronic Resource
    Electronic Resource
    The effect of right terminal repeat deletion on the oncogenicity of the T-Region of pTiT37 (1985)
    Springer
    Plant molecular biology 5 (1985), S. 3-11 
    Details
    ISSN: 1573-5028
    Keywords: Agrobacterium ; tumorigenicity ; border repeats ; tmr locus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A modified pTiT37 plasmid was constructed by deleting a 103 base fragment between an AhaIII and a Bc/I site. This fragment, located to the right of the nopaline synthase gene contains the right terminal 25 base pair repeat sequence which defines the right limit of the T-Region. The effect of this deletion was determined on a number of host plants. In contrast to previous reports, the deletion does not destroy tumorigenicity on all plant species. It had no effect on tumorigenicity when Linum usitatissimum was used as the test species and an attenuating effect when Kalanchoë tubiflora was used. Only when Nicotiana tabacum was used did the mutant appear avirulent. We propose from these data and the phenotype of those tumours that form, that a pseudo border located in the 3′ untranslated region of the ipt locus has been used to provide the right hand limit of the T-Region in the absence of the normal border.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00017868
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  • 48
    Electronic Resource
    Electronic Resource
    Transformation of lily by Agrobacterium (1955)
    Springer
    Euphytica 85 (1955), S. 97-100 
    Details
    ISSN: 1573-5060
    Keywords: Agrobacterium ; transformation ; lily ; β-glucuronidase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Lily cv. Harmony was inoculated with several Agrobacterium strains to study its susceptibility to Agrobacterium infection and transformation. Tumorous tissue formation on inoculated stem internodes of sterile-grown plantlets, as well as expression of a β-glucuronidase marker gene interrupted by an intron in cells of inoculated stem nodes, indicate that the monocotyledon Lilium is a host for Agrobacterium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00023935
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  • 49
    Electronic Resource
    Electronic Resource
    A study of different (CaMV 35S and mas) promoter activities and risk assessment of field use in transgenic rapeseed plants (1955)
    Springer
    Euphytica 85 (1955), S. 411-416 
    Details
    ISSN: 1573-5060
    Keywords: Agrobacterium ; Brassica napus ; CaMV 35S promoter ; mas promoter ; gene expression ; risk assessment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Gene fusions between the β-glucuronidase (GUS) reporter gene and the promoters of the cauliflower mosaic virus 35S RNA transcript (CaMV 35S) and the mannopine synthase (mas) genes were introduced into rapeseed varieties via Agrobacterium-mediated transformation. Fluorometric assay of β-glucuronidase activity indicated different expression patterns for the two promoters. In seedlings, the CaMV 35S promoter had maximum activity in the primary roots, while the mas promoter was most active in the cotyledons. Etiolated seedlings cultured in the dark showed reduced activity of the mas promoter. Before vernalization at the rosette stage, both promoters were more active in older plant parts than in younger ones. At this stage the highest activity was recorded in cotyledons. After the plants had bolted reduced promoter function was detected in the upper parts of the transformed plants. Both promoters were found to be functional in the majority of the studied organs of transgenic rapeseed plants, but the promoter activity varied considerably between the organs at different developmental stages. The ability of pollen to transfer the introduced genes to other varieties and related species (e.g. Brassica napus and Diplotaxus muralis) by cross-pollination was studied in greenhouse experiments, and field trials were carried out to estimate the distance for biologically-relevant gene dispersal. In artificial crossing, the introduced marker gene was transferable into other varieties of Brassica napus. In field trials, at a distance of 1 metre from the source of transgenic plants, the frequency of an outcrossing event was relatively high (10-3). Resistant individuals were found at 16 and 32 metres from the transgenic pollen donors, but the frequency of an outcrossing event dropped to 10-5.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00023974
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  • 50
    Electronic Resource
    Electronic Resource
    An assessment of morphogenic and transformation efficiency in a range of varieties of potato (Solanum tuberosum L.) (1955)
    Springer
    Euphytica 85 (1955), S. 101-108 
    Details
    ISSN: 1573-5060
    Keywords: Agrobacterium ; plant regeneration ; potato ; Solanum tuberosum ; tissue culture ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary To provide a truly genotype-independent transformation system, it is necessary to be able to transform a wide range of potato genotypes. The ability to regenerate shoots in vitro was determined for 34 potato varieties using tuber disc explants. Following a culture regime used extensively in previous studies with the variety Desiree, half of the varieties could be regenerated from tuber discs and half could not. From a sample of varieties that could be regenerated from tuber discs, all but one variety gave transgenic plants. Twelve varieties were evaluated for the capacity to regenerate shoots from leaf and internode explants excised from in vitro grown plants. All of the varieties tested regenerated adventitious shoots. Leaf and internode explants from 5 varieties were subsequently used for transformation, and transgenic plants were produced from two potato varieties that did not give transgenic plants from tuber disc explants. Some varieties could not be transformed by either method, and will require modification of the in vitro regeneration and transformation system to be successful.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00023936
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  • 51
    Electronic Resource
    Electronic Resource
    Some methodological aspects of apple transformation by Agrobacterium (1955)
    Springer
    Euphytica 85 (1955), S. 131-134 
    Details
    ISSN: 1573-5060
    Keywords: apple ; transformation ; Agrobacterium ; preculture ; azacytidine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Leaf explants of apple cvs Gala and Golden Delicious were infected with the Agrobacterium tumefaciens strain AGL0(pMOG410). The effects of a 2 d preculture of the explants before infection and the addition of 5-azacytidine to the selection medium were studied. The percentages of GUS-positive explants after 5 w did not significantly alter due to these treatments. One of the ‘Gala’ shoots, which was removed from a leaf explant cultured for 8 w on selection medium, proved to be GUS-positive and will be analyzed further. In general, however, it should be concluded that regeneration of transgenic shoots directly from leaf tissue was not very effective.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00023941
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