Submitted to: American Phytopathology Society
Publication Type: Proceedings
Publication Acceptance Date: 7/15/2008
Publication Date: 7/22/2008
Citation: Lee, S., Jia, Y. 2008. Analysis of genomic variation of rice blast resistance rene Pi-ta in oryza species. American Phytopathology Society. 98:S87. Interpretive Summary:
Technical Abstract: The resistance gene Pi-ta in rice has been deployed worldwide to prevent the infection by the blast pathogen, Magnaporthe oryzae. The genomic region spanning Pi-ta in 144 accessions composed of seven Oryza species has been sequenced to determine DNA sequence variation of Pi-ta. Presently, three significant clades of the Pi-ta alleles were found among 144 accessions. Nucleotide differences in the 5’ leader and 3’ trailer regions were observed to distinguish among different Pi-ta variants. The first significant insertion of 266bp was observed at the translation start codon ATG in 19 accessions composed of O. Sativa (red rice and ancient rice cultivars Carolina Gold and Blue rose), O. rufipogon, O. nivara. O. barthii, O. glaberima and O. glumaepatula. Additional significant insertion of 313bp was observed at 465bp after the translation stop codon TGA in 3’ trailer region in six accessions of O. barthii, O. glaberima and O. glumaepatula. Phylogenetic analysis of Pi-ta alleles among 144 accessions revealed four genetic linkage groups distinguishing each Oryza species. Pi-ta alleles in O. rufipogon showed the highest similarity with O. sativa (Asian, US cultivars, and red rice). The Pi-ta alleles in red rice were more similar to both Asian and US cultivars than to wild rice relatives. Studies to determine how these sequence variations may impact Pi-ta in resistance and help to understand the origin of Pi-ta will be presented.