Skip to main content
ARS Home » Southeast Area » Stuttgart, Arkansas » Dale Bumpers National Rice Research Center » Research » Publications at this Location » Publication #413694
Research Project: Broadening and Strengthening the Genetic Base of Rice for Adaptation to a Changing Climate, Crop Production Systems, and Markets

Location: Dale Bumpers National Rice Research Center

Title: Surveys of Magnaporthe oryzae genotypes in breeding stations and commercial rice fields in Arkansas, Louisiana and Puerto Rico from 2017 to 2019

Author
item YIXIAO, HUANG - Orise Fellow
item JIA, YULIN
item WAMISHE, YESHI - Retired Non ARS Employee
item JIA, MELISSA

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/15/2024
Publication Date: 7/30/2024
Citation: Yixiao, H., Jia, Y., Wamishe, Y., Jia, M.H. 2024. Surveys of Magnaporthe oryzae genotypes in breeding stations and commercial rice fields in Arkansas, Louisiana and Puerto Rico from 2017 to 2019. Abstract. Plant Health 2024, July 27-30, 2024. Memphia, Tennessee.

Interpretive Summary:

Technical Abstract: Major resistance (R) gene mediated resistance to rice blast fungus Magnaporthe oryzae is often overcome by the fungus due to the occurrences of new races with altered corresponding avirulence (AVR) genes. In this present study, regional blast diseased rice tissue samples were collected from breeding stations and commercial rice fields in Arkansas, Louisiana and Puerto Rico from 2017-2019 to determine the efficacy of major R genes, Pi-ta, Pik, Pizt, Pi9, and Pi33. A total of 185 blast isolates were purified to examine the existence of AVR genes AVR-Pita1, AVR-Pib, AVR-Pik, AVR-Pizt, AVR-Pi9 and ACE1. Their genotypes were examined using 10 simple sequence repeat (SSR) markers. AVR-Pizt and AVR-Pita1 were found in all isolates suggesting that major R genes Pizt and Pi-ta are still effective to prevent infections by these isolates. Among the 185 isolates, 117 contained all the 6 AVR genes and three other groups contained 3-5 AVR genes suggesting various degrees of race shift in these isolates. SSR data revealed endemicity in genetic backgrounds among isolates from Arkansas, whereas migration in isolates between Louisiana and Puerto Rico. Structure analysis of SSR data suggested two major clusters with 46 combinations. The isolates in Arkansas showed high genetic diversity dominated by one genotype. The isolates in Louisiana were also genetically diversified without any obvious predominant group. The isolates in Puerto Rico have the lowest heterozygosity. These data reveal contemporary genetic changes of rice blast fungus and are useful for guiding the deployment of major R genes in these regions.