Chinese Bulletin of Botany ›› 2023, Vol. 58 ›› Issue (5): 743-749.DOI: 10.11983/CBB22183

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Genotypic Diversity and Pathogenisity of Xanthomonas oryzae pv. oryzae Isolated from Southern China in 2019-2021

Tian Chuanyu1,2, Fang Yanli1,2, Shen Qing3, Wang Hongjie1,2, Chen Xifeng1, Guo Wei1, Zhao Kaijun2, Wang Chunlian2,4(), Ji Zhiyuan2()   

  1. 1. College of Life Sciences, Zhejiang Normal University, Jinhua 321004, China
    2. National Key Facility for Crop Gene Resources and Genetic Improvement (NFCRI), Institute of Crop Sciences, Chinese Academy of Agriculture Sciences (CAAS), Beijing 100081, China
    3. Suzhou Municipal Plant Protection and Quarantine Station, Suzhou 215006, China
    4. National Nanfan Research Institute (Sanya), Chinese Academy of Agricultural Sciences, Sanya 572024, China
  • Received:2022-08-03 Accepted:2023-02-09 Online:2023-09-01 Published:2023-09-21
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    † These authors contributed equally to this paper.

Abstract: Although resistant cultivars have been widely employed as the most economical and effective way to control bacterial blight (BB) in rice, the outbreak of BB reoccured in Southern China in recent years. In order to investigate the cause for the recent outbreak of BB in China, we collected the rice leaves with typical BB symptom from paddies in eight southern provinces (Hainan, Yunnan, Guangxi, Guangdong, Fujian, Hunan, Zhejiang, and Jiangsu) in 2019 to 2021. A total of 97 Xanthomonas oryzae pv. oryzae (Xoo) strains isolated from the BB-diseased leaves were divided into 10 genotypes by Southern hybridization detection of transcription activator-like effectors (tale), of which genotype V was the representative of the dominant population. The representative strains of each genotype were applied to inoculated rice accessions with different resistance (R) gene. The inoculation results revealed that traditional major R genes such as Xa3 and Xa4 were only effective against a small number of the newly isolated Xoo strains, whereas Xa7 and Xa23 still had broad-spectrum resistance to all (or the majority of) these strains. We concluded that the cause for the recent outbreak of rice BB in Southern China is most likely the insufficient use of effective BB resistance genes in the new rice varieties. Exploring and utilizing excellent resistance gene resources is still the most ideal way to prevent and control BB.

Key words: bacterial blight, resistance gene, transcription activator-like effector, strain virulence, rice