内蒙古红豆草黄萎病菌的分离鉴定及其生物学特性

依照柯赫氏法则,利用形态学结合分子生物学的方法首次对内蒙古自治区呼和浩特市中国农科院草原研究所沙尔沁基地红豆草疑似黄萎病的病样进行分离和鉴定,利用蘸根接种法对病原菌的致病性进行测定。同时,首次在室内条件下对病菌的生物学特性,如生长最适温度、酸碱度以及碳源、氮源对病原菌生长速率和产孢量的影响进行了研究。结果表明,引起沙尔沁基地红豆草黄萎病的病原菌为大丽轮枝孢菌,菌株具有较宽的温度和酸碱度适应范围,最适于菌株生长和产孢的温度均为25℃,最适于菌株生长和产孢的pH值范围分别为7~10和5~6。在碳源选择上,大丽轮枝孢菌在可溶性淀粉上的生长速度最快,而蔗糖最有利于其产孢。在氮源选择上,大丽轮枝孢菌在牛肉膏和L-脯氨酸上的生长速度较快,且L-脯氨酸最有利于其产孢。

Isolation,Identification and Biological Characteristics of Pathogenic Microorganism Causing Verticillium Wilt of Sainfoin in Inner Mongolia

In order to determine whether the disease suspected to be sainfoin Verticillium Wilt was caused by Verticillium spp.,and to further identify the species of the pathogen,the diseased samples in Shaerqin base of Grassland Research Institute of Chinese Academy of Agricultural Sciences in Hohhot,Inner Mongolia were collected from a sainfoin field and the pathogen was isolated and identified by morphological and molecular biological methods according to Koch’s postulate for the first time,and the pathogenicity of the pathogen was determined by root-dipping inoculation method.At the same time,it was the first time to study the biological characteristics of the pathogen under indoor conditions,such as the effects of optimum temperature,pH,carbon and nitrogen source on the growth rate and sporulation of the pathogen.The results showed that Verticillium dahliae Kleb was the pathogen causing the Verticillium Wilt of sainfoin in Shaerqin base.The strain had a wide range of temperature and pH,and the optimum temperature for mycelia growth and sporulation was 25℃.The suitable pH value for mycelia growth and sporulation were 7~10 and 5~6,respectively.V.dahliae grew fastest on the medium with soluble starch as the carbon sources,but sucrose was the best nitrogen source for sporulation.Beef extract and L-proline were the best nitrogen source for mycelia growth,and L-proline was the best nitrogen source for sporulation.