ISSN:
1432-2242
Keywords:
Key words Triticum tauschii
;
Starch branching enzyme genes
;
Wheat
;
Endosperm
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract A genomic DNA fragment from Triticum tauschii, the donor of the wheat D genome, contains a starch branching enzyme-I (SBE-I) gene spread over 6.5 kb. This gene (designated wSBE I-D4) encodes an amino acid sequence identical to that determined for the N-terminus of SBE-I from the hexaploid wheat (T. aestivum) endosperm. Cognate cDNA sequences for wSBE I-D4 were isolated from hexaploid wheat by hybridisation screening from an endosperm library and also by PCR. A contiguous sequence (D4 cDNA) was assembled from the sequence of five overlapping partial cDNAs which spanned wSBE I-D4. D4 cDNA encodes a mature polypeptide of 87 kDa that shows 90% identity to SBE-I amino acid sequences from rice and maize and contains all the residues considered essential for activity. D4 mRNA has been detected only in the endosperm and is at a maximum concentration mid-way through grain development. The wSBE I-D4 gene consists of 14 exons, similar to the structure for the equivalent gene in rice; the rice gene has a strikingly longer intron 2. The 3′ end of wSBE I-D4 was used to show that the gene is located on group 7 chromosomes. The sequence upstream of wSBE I-D4 was analysed with respect to conserved motifs.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s001220051052
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