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ARS Home » Southeast Area » Stuttgart, Arkansas » Dale Bumpers National Rice Research Center » Research » Publications at this Location » Publication #307738
Title: Characterization of rice blast resistance genes in rice germplasm with monogenic lines and pathogenicity assays

Author
item WANG, JICHUN - Institute Of Plant Protection - China
item CORRELL, JAMES - University Of Arkansas
item Jia, Yulin

Submitted to: Crop Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/18/2015
Publication Date: 3/23/2015
Citation: Wang, J., Correll, J.C., Jia, Y. 2015. Characterization of rice blast resistance genes in rice germplasm with monogenic lines and pathogenicity assays. Crop Protection. 72:132-138.

Interpretive Summary: Resistance (R) genes have been effectively deployed in preventing rice crop losses due to rice blast disease caused by the fungus Magnaporthe oryzae. In the present study, we studied the interaction between 24 monogenic lines carrying at least one major R gene with 14 common races of M. oryzae. We found that the monogenic lines carrying Pi9 and Pita-2 provided broad spectrum resistance to many of races of the blast pathogen. Ten out of the 14 races caused disease on some of the monogenic lines, and more than 50% of the races caused disease across all monogenic lines. Genetic diversity of all 14 races was verified by using genomic analysis. Based on these findings, a useful strategy of pyramiding blast R genes in new cultivars was proposed. Eight rice cultivars were identified that carry more than two blast R genes and can serve as useful breeding resources to improve blast resistance in the US and worldwide.

Technical Abstract: Resistance (R) genes have been effectively deployed in preventing rice crop losses due to the fungus Magnaporthe oryzae. In the present study, we studied the interaction between 24 monogenic lines carrying at least one major R gene, Pia, Pib, Pii, Pik, Pik-h, Pik-m, Pik-p, Pik-s, Pish, Pit, Pita, Pita-2, Piz, Piz-t, Pi1, Piz-5, Pi3, Pi5(t), Pi7(t), Pi9, Pil1(t), Pi12(t), Pi19, or Pi20, used in rice breeding programs, with 14 common races of M. oryzae. We found that the monogenic lines carrying Pi9 and Pita-2 provided broad spectrum resistance to 92.9% and 78.6% of the races, respectively. The races IB33(FLN9), IE1(ZN13), IB1(ZN15), IC1(120), IE1K(TM2), IA1(ARB20112-114), IB49(Unnamed), IH1(Unnamed), ID1(ZN42), and IC17(ZN57) were highly virulent on some monogenic lines, and more than 50% of the isolates were pathogenic across all monogenic lines. Genetic diversity of the 14 races was verified by Rep-PCR. Based on these data, a useful strategy of pyramiding blast R genes against pathogenic M. oryzae races was proposed. Eight global rice cultivars were identified to carry more than two blast R genes using representative races and R gene specific primers. These findings are important for breeding for improved blast resistance in the US and worldwide.