Plant & Animal Genomes XI Conference Plant & Animal Genomes XI ConferenceJanuary 11-15, 2003
Town & Country Convention Center
San Diego, CA
Poster: Genome Sequencing & ESTs
Aegilops tauschii constitutes a valuable resource of variability for broadening the genetic base of cultivated bread wheat. We are exploring the extent of genetic diversity in a large number (n=50) of Ae. tauschii, particularly focusing on the Hardness locus which bears the puroindoline a (pinA) and b (pinB) genes. Additionally, we are examining variation in the closely related (and closely located) gene, GSP-1. Multiple sequence comparisons identified a group of accessions that shared the same nucleotide sequences as those found in Triticum aestivum. Estimates of nucleotide diversity (ð) indicated that pinB is the most polymorphic (ð = 0.03) of the three genes with an average number of 13.3 nucleotide differences and up to 30 nucleotide (nt) changes in an individual accession (which translated to 14 amino acid (aa) differences). Conversely, pinA revealed only three polymorphic sites–one was common to all and conferred an ARG to GLN change at position 58. GSP-1 varied little also with only 5 polymorphic nt positions and a total of 2 aa differences. Overall sequence analysis identified 13 novel gene sequence combinations for the 3 genes, 7 of which were unique. The sequence variation resolved here will help elucidate what kind of variation is important for the function of these genes, as well as identify novel Ae. tauschii genotypes that may broaden the range in wheat grain texture. Lastly, the results contribute to the understanding of what present-day Ae. tauschii accession is most closely related to the donor of the D-genome of modern wheat.