Submitted to: Plant and Animal Genome Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 1/1/2009
Publication Date: 1/10/2009
Citation: Xueyan, W., Fjellstrom, R.G., Jia, Y., Yan, W., Jia, M.H., Scheffler, B.E., Dianxing, W., Qingyao, S., McClung, A.M. 2009. Worldwide distribution and origin of rice blast resistance gene Pi-ta. In: Proceedings of the Plant and Animal Genome Conference XVII, January 10-14-2009, San Diego, CA. P116.
Technical Abstract: Pi-ta is a single resistance (R) gene encoding a putative NBS type receptor with single amino acid alanine at position 918 (G at 6640) determining the resistance specificity. The distribution and origin of the Pi-ta gene were investigated in a germplasm core collection consisting of 1790 accessions representing 70% of genetic diversity of the entire USDA collection. The Pi-ta allele was identified in 159 accessions. These Pi-ta containing rice accessions were determined to be genetically diverse by cluster analysis using diagnostic genome wide SSRs. The presence of the Pi-ta allele in diverse cultivars worldwide suggests that the Pi-ta allele has multiple origins. Sample sequencing of the sub genomic region (the intron and carboxyl terminal region) of the Pi-ta gene revealed that only one resistant Pi-ta allele encoding a functional protein with alanine at 918 was found in all resistant accessions. Functional analysis using both virulent and avirulent isolates revealed new R genes in 83 rice accessions. This knowledge is important for breeding for improved resistance to blast worldwide. Understanding the distribution and origin of resistance genes in rice germplasm should benefit the utilization of R genes for breeding.