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United States Department of Agriculture

Agricultural Research Service

Title: RICE PI-TA GENE CONFERS RESISTANCE TO TWO MAJOR PATHOTYPES OF THE RICE BLAST FUNGUS IN THE U.S.)

Author
item Jia, Yulin
item Wang, Zhonghua
item Fjellstrom, Robert
item Moldenhauer, Karen
item Simmons, Cuwanda
item Rutger, J

Submitted to: Rice Technical Working Group Meeting Proceedings
Publication Type: Abstract only
Publication Acceptance Date: 2/29/2004
Publication Date: 2/1/2005
Citation: Jia, Y., Wang, Z., Fjellstrom, R.G., Moldenhauer, K., Flowers, C.B., Rutger, J.N. 2005. Rice pi-ta gene confers resistance to two major pathotypes of the rice blast fungus in the U.S. [abstract]. Rice Technical Working Group Meeting Proceedings. Abstract p. 84.

Interpretive Summary:

Technical Abstract: Blast is a serious rice disease in the Southern US. The Pi-ta gene in rice prevents the infections of Magnaporthe grisea isolates containing the avirulence AVR-Pita gene. Pi-ta encodes a putative cytoplasmic receptor that appears to bind to a predicted processed AVR-Pita to elicit a defense response. The landrace cultivar Tetep was the donor for the Pi-ta gene for the US cultivar, Katy. Subsequently, Katy was the Pi-ta donor for additional US cultivars, Drew and Kaybonnet. The objective of this study is to determine the role of Pi-ta in resistance to contemporary blast pathogen races in the Southern US. Field surveys have indicated that the races IB-49 and IC-17 are the most common in the Southern US. We observed that all of the Pi-ta containing cultivars were resistant to both major pathotypes IB-49 and IC-17 of M. grisea. The presence of Pi-ta as determined by DNA markers for the Pi-ta gene completely correlated with resistance to both IB-49 and IC-17. The resistance was further investigated using a marker for the resistant Pi-ta allele in a F2 population of 1345 progeny of a cross with Katy. Resistance to IC-17 was conferred by a single dominant gene, and Pi-ta was not detected in susceptible individuals. Another F2 population of 377 individuals of a reciprocal cross was used to verify the conclusion that resistance to IC-17 was conferred by a single dominant gene. In this cross, individuals resistant to IC-17 were also resistant to IB-49. The presence of Pi-ta and resistance to IB-49 was also correlated with additional crosses involving another Pi-ta containing rice culitvar. A pair of primers that specifically amplifies a susceptible pi-ta allele was developed to verify the absence of the dominant Pi-ta gene. These data suggest that Pi-ta is responsible for resistance to IB-49 and IC-17. The correlation of Pi-ta with resistance to both M. grisea pathotypes suggests they contain functional AVR-Pita genes. Currently, structural and functional analysis of AVR-Pita alleles from IB-49 and IC-17 are in progress. Completion of this task will enhance the understanding of molecular evolution of the AVR-Pita gene. In the future, DNA markers for Pi-ta can be used to follow the incorporation of Pi-ta into advanced breeding lines containing additional blast resistance genes to reach a broad spectrum of resistance to different fungal isolates.

Last Modified: 8/24/2016
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