Journal of Resources and Ecology ›› 2011, Vol. 2 ›› Issue (2): 181-185.DOI: 10.3969/j.issn.1674-764x.2011.02.012

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Geographic Distribution of Avirulence Genes in Rice Blast Fungus in Yunnan Province, China

LI Jinbin1,2, YANG Jing1, LIU Lin1, HE Hanming1, HE Xiahong1, ZHU Youyong1, LI Cheng-yun1   

  1. 1 Key Laboratory of Agro-Biodiversity and Pest Management of Education Ministry of China, Yunnan Agricultural University, Kunming 650201, China;
    2 Agricultural Environment and Resources Research Institute, Yunnan Academy of Agricultural Sciences, Kunming 650205, China
  • Received:2011-01-04 Revised:2011-03-21 Online:2011-06-30 Published:2011-06-28
  • Supported by:

    This work was supported by the National Natural Science Fund (30860161) and National Basic Research Program (No. 2011CB100400) and The Ministry of Science and Technology of China, the Natural Science Fund (2010ZC173).

Abstract: Knowledge of the geographic distribution and frequency of avirulence genes will contribute to the development of strategies to effectively use rice varieties that carry various resistances genes, including combinations of varieties in mixture cropping systems. Here, we analyzed the geographic distribution and frequencies of avirulence genes in rice blast fungus using samples collected from 11 prefectures across Yunnan province, China. A total of 467 single spore isolates were assayed for pathotypes based on their reaction to 20 rice blast resistance monogenic lines. The results revealed that frequencies of avirulence genes among 10 prefectures showed insignificant difference, but frequencies of avirulence genes in Xishuangbanna showed significant differences compared to the remaining 10 prefectures. The avirulence genes Avr-Pi9, Avr-Piz and Avr-Pizt were observed at the highest frequency in blast isolates from the 11 prefectures; their average frequency was greater than 80%. Our results imply that the composition and distribution of rice genetic diversity are more important than climate and other environment conditions for formation and maintenance of rice blast fungus genetic diversity. Using average frequencies, the avirulence genes can be categorized into 4 groups. There were significant differences of frequencies of avirulence genes among different groups, while insignificant differences observed within any group. These results will provide useful information for evaluation of resistance genes and effective management of rice blast disease.

Key words: Magnaporthe grisea, avirulence gene, rice monogenic line, frequency, geographic distribution