水稻新叶斑病害病原的鉴定及其与稻瘟病的比较研究

Identification of the Pathogen of a New Rice Leaf Spot Disease and the Differences between Leaf Spot Disease and Rice Blast

【目的】明确2018年海南陵水大面积发生的水稻叶斑病病原及对水稻生产的潜在危害。【方法】通过形态分类结合分子生物学手段,对病原进行系统的分类鉴定;采用离体叶鞘接种对病原菌侵染水稻的早期生物学过程进行详细观察;利用喷雾接种法研究病原菌对13个水稻品种的致病性。【结果】明确了海南水稻叶斑病的病原为子囊菌门(Ascomycota)座囊菌纲(Dothideomycetes)格孢腔菌目(Pleosporales)格孢腔菌科(Pleosporaceae)弯孢属(Curvularia)新月弯孢(C.lunata)。典型症状是在水稻叶片形成较大的椭圆形褐色病斑;其侵染水稻的生物学过程与稻瘟病菌相似,但从分生孢子萌发到菌丝扩展的时间更短。该真菌对供试的13个水稻材料表现出了强致病性。【结论】鉴定了1种对水稻生产具有潜在威胁的新叶斑病病原,明确了该病原引起的水稻病害区别于稻瘟病的典型症状特征,该病原对供试的13个水稻材料均表现出明显的致病性,包括广谱抗稻瘟病水稻地谷。研究结果有助于该病害的正确识别和有效防治,为水稻抗病育种提供了新信息。

[Purpose]To identify the pathogen and potential threat of a new rice leaf spot disease and potential threats of this disease to rice production,which occurred in Lingshui,Hainan Province in 2018.[Methods]We carried out the identification of pathogen causing rice leaf spot disease by morphological classification combined with molecular biology methods,the investigation of early biological process of pathogen infection in rice,and the pathogenicity identification of pathogen on 13 rice varieties by spraying inoculation.[Results]The pathogen caused leaf spot disease of rice in Hainan is fungi Curvularia lunata,belonging to Ascomycota,Dothideomycetes,Pleosporales,Pleosporaceae,Curvularia.The typical symptom of leaf spot disease is the formation of large oval brown spots on rice leaves of infected plants.Although the biological process of rice infection by C.lunata is similar to that of Magnaporthe oryzea,the time from conidial germination to mycelial ex-pansion is shorter.The C.lunata pathogen showed obvious pathogenicity to 13 rice materials tested in this study.[Conclusion]We clarified that the pathogen caused rice leaf spot disease in Lingshui of Hainan Province is C.lunata,the typical symptoms of leaf spot disease are different from rice blast,and the pathogenicity of C.lunata to 13 rice materials tested in this study,including broad-spectrum blast resistant rice Digu.Our results are helpful for the correct recognition and effective control of rice disease,providing new information for rice disease resistance breeding.