何世芳，桑维钧，曹毅，孙光军，潘忠梅，陆宁，陈兴江

摘  要：为明确贵州烟草弯孢菌叶斑病病原菌种类及生物学特性，分别采用组织分离法和离体叶片接種法对其病原菌进行分离和致病性测定，使用形态特征结合分子生物学方法对病原菌进行分类鉴定，并对其生物学特性进行研究。结果表明，该病原菌在以ITS序列构建的发育树中与棒状弯孢（Curvularia clavata）聚为一支，且支持率为100%，结合形态特征将其鉴定为棒状弯孢。生物学特性研究表明，病原菌菌丝生长最适温度为28 ℃，最适pH为8，在燕麦琼脂（OA）培养基上生长最快，以可溶性淀粉为碳源、牛肉浸粉为氮源时对菌丝生长最有利;菌丝致死温度为53 ℃，10 min，光照对菌丝生长无显著影响。研究结果可为烟草弯孢菌叶斑病防治提供理论依据。

关键词：烟草;叶斑病;棒状弯孢;病原菌鉴定;生物学特性

Identification and Biological Characterization of Curvularia clavata Causing the Tobacco Leaf Spot Disease

HE Shifang1，2， SANG Weijun1*， CAO Yi2*， SUN Guangjun3， PAN Zhongmei1，2， LU Ning2， CHEN Xingjiang2

（1. College of Tobacco， Guizhou University， Guiyang 550025， China; 2. Guizhou Academy of Tobacco Science， Guiyang 550081， China; 3. Tobacco Department Guizhou Branch of China Tobacco Corporation， Guiyang 550025， China）

Abstract： To clarify the pathogen causing leaf spots of tobacco in Guizhou Province and its biological characteristics， the pathogen was obtained by using the method of tissue isolation. Its pathogenicity was tested in vitro with inoculated leaves， and the pathogen was classified and identified with morphological characteristics combined with molecular biological methods. The biological characteristics of the pathogen were also studied. The results showed that the pathogen clustered with Curvularia clavata in the phylogenetic tree based on ITS sequence， and the support rate was 100%. Combined with the morphological characteristics， the pathogen was identified as Curvularia clavata. The study of biological characteristics showed that the optimum temperature for mycelium growth was 28 ℃， the optimum pH was 8， the fastest growth was on oat agar （OA）， and it was most favorable for mycelium growth when soluble starch was used as carbon source and beef powder as nitrogen source， and the lethal temperature of mycelium was 53 ℃ and 10 min. The light had no significant effect on mycelial growth of Curvularia clavata. The results can provide a theoretical basis for the control of tobacco Curvularia leaf spot.

Keywords： tobacco; leaf spot disease; Curvularia clavata; pathogen identification; biological characteristics

烟草是我国重要的经济作物[1]。近年来，由于烟草种植制度改变、气候条件变化、种植品种单一和烟田连作比例较高等原因，导致烤烟病害呈明显上升趋势。贵州是我国第二大烟区，常年种植面积达12余万公顷，在烤烟生长中后期叶斑类病害在部分烟区发生偏重，严重影响烟叶生产[2]，病害防治形势日益严峻。

弯孢属真菌是一类重要的植物病原菌，其种类繁多[3-4]，可危害玉米、燕麦、水稻、甘蔗和小麦等多种禾本科植物 [5-10]，引起叶斑、种子变色和苗枯等症状[11]。20世纪60年代印度北部首次报道了烟草弯孢叶斑病，我国于90年代首次在广西壮族自……