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ARS Home » Southeast Area » Stuttgart, Arkansas » Dale Bumpers National Rice Research Center » Research » Publications at this Location » Publication #301007
Title: Implication of co-evolutionary dynamics for genetic resistance to rice blast fungus

Author
item Jia, Yulin

Submitted to: Rice Technical Working Group Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 2/18/2014
Publication Date: 12/15/2014
Citation: Jia, Y. 2014. Implication of co-evolutionary dynamics for genetic resistance to rice blast fungus. Proc. 35th Rice Tech. Work. Group Meet., New Orleans, LA, p.39. Feb 18-21, 2014. CDROM.

Interpretive Summary:

Technical Abstract: Plant resistance (R) genes play important roles in fighting against pathogens. Over 100 R genes and some of their cognate pathogen effectors have been molecularly characterized. It was found that most R genes encode predicated receptor proteins with nucleotide binding sites (NBS) and leucine rich repeats (LRR). In contrast, the cognate pathogen effectors are random molecules without common motifs. Understanding the molecular dynamics of host-pathogen co-evolution has been a subject for intensive investigation worldwide. Blast disease of rice (Oryza sativa) caused by the fungus Magnaporthe oryzae is one of the most serious crop diseases. O. sativa has been grown as an important food for human consumption for thousands years, and can be found in most countries around the globe. Thus far, O. sativa has the following five subgroups: aus (AUS), indica (IND), temperate japonica (TEJ), tropical japonica (TRJ), and aromatic (ARO). In the present study, the deployed major blast R genes, Pi-ta, Pi-b, and Pi-z in 1800 rice germplasm, collected from over 100 countries, from the National Small Grains Collection (NSGC) have been analyzed using DNA markers and pathogenicity assays. Pi-ta and Pi-b were mostly found in IND and TRJ, whereas Pi-z was found in all subgroups except for ARO. Twenty rice germplasms with 2 R genes were only identified in indica cultivars collected from countries in Southeast Asia, China, Africa, South America, South Pacific, Mideast, and Europe. This analysis revealed that one or two R genes have been critical for combating blast disease worldwide. This finding has significant implications for evolution and adaptation of rice blast fungus. New strategies for crop protection will be presented.