基于ITS的烤烟棒孢霉叶斑病菌分子鉴定与生物学特性

Molecular Identification and Biological Characteristics of Corynespora FlueCured Tobacco Leaf Spot Pathogen Based on ITS

为明确贵州烤烟棒孢霉叶斑病病原菌种类及生物学特性,本研究采用常规组织分离法对贵州省采集的烟叶进行病原菌分离与纯化,根据柯赫氏法则进行致病性测定,得到两个代表菌株YC1002和YC1104,通过形态学特征及ITS序列将其鉴定为多主棒孢霉(Corynespora cassiicola)。生物学特性研究结果表明:病原菌在胡萝卜琼脂培养基(CA)上生长最快,在燕麦琼脂培养基(OA)上产孢量最多,最适生长温度为30℃,最适宜pH 6,菌丝致死温度为52℃10 min,光照对菌落生长影响不大。最适碳源为麦芽糖和可溶性淀粉,最适氮源为甘氨酸和苏氨酸。研究结果可为生产上烤烟棒孢霉叶斑病的有效防治提供一定的理论依据。

In order to clarify the pathogen species and biological characteristics of Corynespora leaf spot of flue-cured tobacco in Guizhou, In this study, the conventional tissue separation method to isolate and purify tobacco leaf pathogens collected in Guizhou Province, and two representative strains YC1002 and YC1104 were obtained. According to Koch’s rule, these two strains were determined to be the pathogens of Corynespora flue-cured leaf spot. It was identified as Corynespora cassiicola by morphological characteristics ITS sequence. The results of biological characteristics study showed that the pathogenic bacteria grew fastest on carrot agar medium(CA), and produced the most spores on oat agar medium(OA). The optimum growth temperature was 30 ℃, the optimum pH was 6, the lethal temperature of mycelium is 52 ℃ for 10 min, and the light has little effect on the colony growth.The most suitable carbon sources are maltose and soluble starch, and the most suitable nitrogen sources are glycine and threonine. The research results can provide a certain theoretical basis for the effective control of Corynespora leaf spot on the production of flue-cured tobacco.