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ARS Home » Southeast Area » Stuttgart, Arkansas » Dale Bumpers National Rice Research Center » Research » Publications at this Location » Publication #370644
Research Project: Gene Discovery and Crop Design for Current and New Rice Management Practices and Market Opportunities

Location: Dale Bumpers National Rice Research Center

Title: A new haplotype of rice blast resistance gene Ptr in weedy rice confers resistance to the most virulent race of M. oryzae

Author
item ZHAO, HAIJUN - Orise Fellow
item Jia, Yulin
item LIU, YAN - University Of Arkansas

Submitted to: Rice Technical Working Group Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 12/4/2019
Publication Date: 1/6/2021
Citation: Zhao, H., Jia, Y., Liu, Y. 2021. A new haplotype of rice blast resistance gene Ptr in weedy rice confers resistance to the most virulent race of M. oryzae. Proceedings of 38th Rice Technical Working Group Meeting, February 24-27, 2020, Orange Beach, Alabama. p 78. Electronic Publication.

Interpretive Summary:

Technical Abstract: Blast disease of rice caused by the filamentous fungus Magnaporthe oryzae (syn. Maganporthe grisea) and weedy rice (Oryza sativa indica) are two of the most significant constraints of rice production worldwide. Major resistance (R) genes are the primary means of preventing infections by M. oryzae strains carrying the cognate avirulence (AVR) genes. However, the instability of M. oryzae AVR genes often challenges the stability of deployed R genes. Searching for more effective blast R genes from different genetic resources is essential to manage rice blast disease. In our previous evaluation of germplasm, we determined that rice blast R gene Ptr confers resistance to several US blast races resistance except for the most virulent blast race, IB33. Ptr is a new class of blast resistance gene. In the present study we show that the Ptr protein with minor amino acid variation encoded by the Ptr allele, PtrBHA in a late-flowering black hull weedy rice, MS-1996-9 (PI 653419), here referred to as RR20, from Mississippi is responsible for resistance to IB33. The resistance gene to IB33 was mapped between single nucleotide polymorphic markers (SNP) 10.633,942bp and 10.820,033 bp with the closest SNP at 10.724,430 bp, excluding Pi-ta which is also near this region. A gene specific marker for Ptr was developed to examine the existence of PtrBHA in each individual of a mapping population derived from RR20 x (DGWG) through disease reactions using IB33. The presence of the gene specific marker of PtrBHA was correlated with the resistant reaction to IB33 suggesting that PtrBHA in RR20 is responsible for resistance against IB33. These findings suggest that a natural allele of Ptr in RR20 is a novel and effective blast R gene for breeders to deploy for resistance to this race of blast that currently does not exist in any US cultivar.