【摘要】 种植抗病品种一直是防控水稻白叶枯病(bacterial blight,BB)最有效的措施。近年来,白叶枯病在我国多地呈现“老病新发”态势。为查明近期白叶枯病成灾的原因,2019–2021年间,在南方8省(海南、云南、广西、广东、福建、湖南、浙江和江苏)病害重发生田块采集叶片,分离获得野生白叶枯病菌(Xanthomonas oryzae pv.oryzae,Xoo)。通过对主效毒性因子基因型tale (transcription activator-like effectors)进行Southern杂交检测,将新分离的97株Xoo菌株划分为10个基因型,其中基因型V是优势种群代表。选取各基因型的代表菌株,剪叶接种携带主要抗病基因(R gene)的水稻(Oryza sativa)品种,毒力测试结果显示,Xa3和Xa4等传统抗病基因对田间大部分菌株已经丧失抗性,Xa7和Xa23等优异抗病基因对白叶枯病仍具有广谱抗性。研究结果表明,近期“老病新发”的主要原因可能是水稻新品种选育过程中忽视了优异抗白叶枯病基因资源的引入,挖掘与利用优异抗病基因资源仍是防控白叶枯病最理想的途径。更多还原

【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 10genotypes 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 Xa3and 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.更多还原