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New Phytol. 2015 Jun;206(4):1463-75. doi: 10.1111/nph.13310. Epub 2015 Feb 6.

Comparative genomics identifies the Magnaporthe oryzae avirulence effector AvrPi9 that triggers Pi9-mediated blast resistance in rice.

Author information

1
State Key Laboratory of Hybrid Rice, Longping Branch of Graduate School, Central South University, Changsha, 410125, China.
2
State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China.
3
Temasek Life Sciences Laboratory, Department of Biological Sciences, 1 Research Link, National University of Singapore, Singapore.
4
The Key Laboratory of Biopesticide and Chemistry Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
5
International Rice Research Institute, DAPO Box 7777, Metro Manila, 1301, Philippines.
6
College of Agriculture, University of the Philippines, Los Banos, Laguna, 4031, Philippines.
7
Agricultural Environment and Resources Research Institute, Yunnan Academy of Agricultural Sciences, Kunming, 650201, China.
8
Key Laboratory of Agro-Biodiversity and Pest Management of Education Ministry of China, Yunnan Agricultural University, Kunming, Yunnan, 650201, China.
9
Graduate School of Biotechnology, Kyung Hee University, Yongin, 446-701, Korea.

Abstract

We identified the Magnaporthe oryzae avirulence effector AvrPi9 cognate to rice blast resistance gene Pi9 by comparative genomics of requisite strains derived from a sequential planting method. AvrPi9 encodes a small secreted protein that appears to localize in the biotrophic interfacial complex and is translocated to the host cell during rice infection. AvrPi9 forms a tandem gene array with its paralogue proximal to centromeric region of chromosome 7. AvrPi9 is expressed highly at early stages during initiation of blast disease. Virulent isolate strains contain Mg-SINE within the AvrPi9 coding sequence. Loss of AvrPi9 did not lead to any discernible defects during growth or pathogenesis in M. oryzae. This study reiterates the role of diverse transposable elements as off-switch agents in acquisition of gain-of-virulence in the rice blast fungus. The prevalence of AvrPi9 correlates well with the avirulence pathotype in diverse blast isolates from the Philippines and China, thus supporting the broad-spectrum resistance conferred by Pi9 in different rice growing areas. Our results revealed that Pi9 and Piz-t at the Pi2/9 locus activate race specific resistance by recognizing sequence-unrelated AvrPi9 and AvrPiz-t genes, respectively.

KEYWORDS:

AvrPi9; Magnaporthe oryzae; resistance genes; rice; specificity

PMID:
25659573
DOI:
10.1111/nph.13310
[Indexed for MEDLINE]
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