烘烤期烟叶霉烂病病原菌的分离、鉴定及生物学特性

Isolation, Identification and Characterization of the Pathogen of Tobacco Leaf Mold during Flue-curing

为明确云南省烘烤期烟叶霉烂病的病原,采用分子和形态学鉴定方法,依据柯赫氏法则,对病原菌进行分离和鉴定并将其命名为Rhi-1,并初步研究了该病原菌的生物学特性。结果表明,引起该病害的病原菌为米根霉(Rhizopus oryzae)。菌株Rhi-1的气生菌丝旺盛,质地疏松,孢子囊和孢囊孢子直径分别为53~123μm和2.1~9.0μm,两者均呈球形或椭圆形。孢囊孢子萌发的最高温度为44.6℃,水相介质中孢囊孢子热处理10min的致死温度为54℃,菌丝体热处理30min的致死温度为70℃,最适pH为7.0,最佳培养基为PSA。此结果为研究霉烂病发生机制提供了依据。

In recent years,tobacco leaf mold has become a serious disease in tobacco producing areas of Yunnan Province.To clarify the pathogen of the disease,the pathogen was isolated,identified and its biological characteristics were also analyzed based on the Koch’s postulations,morphology observation and molecular technology.The results showed that the aerial hyphae of the strain Rhi-1 is vigorous and loose,with its sporangium diameter being 53-123 μm and its sporangiospore diameter being 2.1-9.0 μm,both being spherical or oval.Combining with the 16s rDNA-ITS sequence analysis,the strain Rhi-1 was identified as Rhizopus oryzae.The highest temperature of spore germination is 44.6 ℃,lethal temperature of the spores is 54 ℃ in hot water bath for 10 min and lethal temperature of the mycelium is 70 ℃ in hot water bath for 30 min.The optimal pH value is 7.0 and the optimal medium is PSA.These results could provide a good basis for pathogenicity studies of the pathogen.