1株人工栽培蛹虫草病原真菌的分离鉴定及生物学特性研究

Identification and Biological Characteristics of a Pathogenic Fungal Strain from Cultivated Cordyceps militaris

为明确蛹虫草(Cordyceps militaris)栽培过程中发现的一种病原真菌及其生长特性,采用组织分离法自发病部位分离获得1株真菌CCBH-L,经柯赫法则确定其致病性,通过形态学特征及ITS序列分析,确定菌株CCBH-L为轮枝样镰刀菌(Fusarium verticillioides)。该病原菌在感染初期,通过竞争生长空间和营养物质,影响蛹虫草菌丝体生长和原基分化,导致子实体畸形,后期菌丝体蔓延至已经形成的子实体,导致子实体生长受阻。该病原菌生长的适宜温度为25~30℃,可见,高温利于该病原菌的生长,其生长的适宜p H值为6.0~8.0,适宜含水量为60%~75%。因此,在蛹虫草栽培过程中,将温度控制在20℃以下,可抑制该病原菌的生长,降低感染率。

In this study,a pathogenic fungal strain CCBH-L of Cordyceps militaris was found and isolated from the infected position by tissue isolation method.Its pathogenicity was tested by Koch’s law.Based on morphological characteristics and ITS sequencing analysis,strain CCBH-L was identified as Fusarium verticillioides.In early stage of infection,F.verticillioides affects mycelium growth and primordium differentiation by competing for growth space and nutrients,resulting in malformation of sporogonium.In later stage,the mycelium spreads to the formed sporogonium of C.militaris.The suitable mycelium growth temperature and p H value of F.verticillioides CCBH-L were within 25-30℃and p H 6.0-8.0 respectively.The suitable water content of the medium was within 60%-75%.Therefore,during the cultivation of C.militaris,controlling the temperature below 20℃can inhibit the growth of the pathogen and reduce the infection rate.