Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1432-203X
    Keywords: Abbreviations: cp-chloroplast; GOT-glutamate-oxaloacetate transaminase; IDH-isocitrate dehydrogenase; mt-mitochondria; PEG-polyethylene glycol; PGI-phosphoglucose isomerase; PGM-phosphoglucomutase; RFLP-restriction fragment length polymorphism ; Keywords: chloroplast, mitochondria, somatic embryogenesis, tissue culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary. Somatic hybridization experiments in Citrus that involve the fusion of protoplasts of one parent isolated from either nucellus-derived embryogenic callus or suspension cultures with leaf-derived protoplasts of a second parent, often result in the regeneration of diploid plants that phenotypically resemble the leaf parent. In this study, plants of this type regenerated following somatic fusions of the following three parental combinations were analyzed to determine their genetic origin (nuclear and organelle): (embryogenic parent listed first, leaf parent second) (1) calamondin (C. microcarpa Bunge) + 'Keen' sour orange (C. aurantium (L.), (2) Cleopatra mandarin (C. reticulata Blanco) + sour orange, and (3) 'Valencia' sweet orange (C sinensis (L.) Osbeck) + 'Femminello' lemon (C. limon (L.) Burm. f.). Isozyme analyses of PGI, PGM, GOT, and IDH zymograms of putative cybrid plants, along with RFLP analyses using a nuclear genome-specific probe showed that these plants contained the nucleus of the leaf parent. RFLP analyses using mtDNA-specific probes showed that these plants contained the mitochondrial genome of the embryogenic callus donor, thereby confirming cybridization. RFLP analyses using cpDNA-specific probes revealed that the cybrid plants contained the chloroplast genome of either one or the other parent. These results support previous reports indicating that acquisition of the mitochondria of embryogenic protoplasts by leaf protoplasts in a prerequisite for recovering plants with the leaf parent phenotype via somatic embryogenesis following somatic fusion.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 100 (2000), S. 1010-1017 
    ISSN: 1432-2242
    Keywords: Key words Tylenchulus semipenetrans ; Bulked segregant analysis ; Linkage map ; QTL ; Molecular markers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Eleven RAPD markers linked to a gene region conferring resistance to citrus nematodes in an intergen-eric backcross family were identified. Two sequence- characterized amplified region markers linked to a citrus tristeza virus resistance gene and one selected resistance gene candidate marker were evaluated for their association with citrus nematode resistance. A nematode-susceptible citrus hybrid, LB6-2 [Clementine mandarin (Citrus reticulata)×Hamlin orange (C. sinensis)], was crossed with the citrus nematode-resistant hybrid Swingle citrumelo (C. paradisi×Poncirus trifoliata) to produce 62 hybrids that were reproduced by rooted cuttings. The plants were grown in a greenhouse and inoculated with nematodes isolated from infected field trees. The hybrids segregated widely for this trait in a continuous distribution, suggesting possible polygenic control of the resistance. Bulked segregant analysis was used to identify markers associated with resistance by bulking DNA samples from individuals at the phenotypic distribution extremes. Linkage relationships were established by the inheritance of the markers in the entire population. A single major gene region that contributes to nematode resistance was identified. The resistance was inherited in this backcross family from the grandparent Poncirus trifoliata as a single dominant gene. QTL analysis revealed that 53.6% of the phenotypic variance was explained by this major gene region. The existence of other resistance-associated loci was suggested by the continuous phenotypic distribution and the fact that some moderately susceptible hybrids possessed the resistance-linked markers. The markers may be useful in citrus rootstock breeding programs if it can be demonstrated that they are valid in other genetic backgrounds.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1432-2242
    Keywords: Key words Disease resistance genes ; Citrus tristeza virus resistance ; Citrus nematode resistance ; Molecular markers ; Genetic mapping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Numerous disease resistance gene-like DNA sequences were cloned from an intergeneric hybrid of Poncirus and Citrus, using a PCR approach with degenerate primers designed from conserved NBS (nucleotide-binding site) motifs found in a number of plant resistance genes. Most of the cloned genomic sequences could be translated into polypeptides without stop codons, and the sequences contained the characteristic motifs found in the NBS-LRR class of plant disease resistance genes. Pairwise comparisons of these polypeptide sequences indicated that they shared various degrees of amino-acid identity and could be grouped into ten classes (RGC1–RGC10). When the sequences of each class were compared with known resistance-gene sequences, the percentage of amino-acid identity ranged from 18.6% to 48%. To facilitate genetic mapping of these sequences and to assess their potential linkage relationship with disease resistance genes in Poncirus, we developed CAPS markers by designing specific primers based on the cloned DNA sequences and subsequently identifying restriction enzymes that revealed genetic polymorphisms. Three of the amplified DNA fragment markers (designated as 18P33a, Pt9a, and Pt8a) were associated with the citrus tristeza virus resistance gene (Ctv), and one fragment (Pt8a) was associated with the major gene responsible for the citrus nematode resistance (Tyr1); both genes are from Poncirus and of importance to citrus survival and production. These polymorphic fragments were located on two local genetic linkage maps of the chromosome region from Ctv to Tyr1. These results indicate that resistance-gene candidate sequences amplified with the NBS-derived degenerate primers are valuable sources for developing markers in disease resistance-gene tagging, mapping, and cloning.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...