紫花苜蓿根腐病原菌--拟枝孢镰刀菌的鉴定及其生物学特性研究

Identification and biological characteristics of Fusarium sporotrichioide isolated from Medicago sativa root

本文对从内蒙古赤峰巴雅尔草业基地紫花苜蓿根部分离到的菌株BYE27-2-5进行了致病性测定、形态学和rDNA-ITS序列分析鉴定及生物学特性测定.结果表明,该菌菌丝生长、产孢和孢子萌发的最适温度分别为25,30和28℃;pH 值5.0～11.0均宜于菌丝生长,产孢最适pH8.0,孢子萌发最适pH7.0;光暗交替利于菌丝生长,光照利于产孢和孢子的萌发;孢子在相对湿度低于75% 不萌发,高于95% 萌发较快;葡萄糖蛋白胨培养基利于菌丝生长和孢子萌发,马铃薯蔗糖琼脂培养基利于产孢;碳源中葡萄糖利于菌丝生长和孢子萌发,蔗糖利于产孢;氮源中蛋白胨利于菌丝生长,酵母膏利于产孢和孢子萌发;菌丝致死温度为54℃（10min）,分生孢子的致死温度为48℃（10min）;根据其形态特征和rDNA-ITS序列分析结果,鉴定其为拟枝孢镰刀菌（犉狌狊犪狉犻狌犿狊狆狅狉狅狋狉犻犮犺犻狅犻犱犲）.

The strain BYE27-2-5 isolated from alfalfa( Medicago sativa) with root rot in north China was comprehensively evaluated by analyses of its biological characteristics,morphology,and ITS sequence. The optimum temperatures for mycelium growth,sporulation,and spore germination were 25℃,30℃,and 28℃,respectively. The strain was able to grow in a p H range of 5. 0- 11. 0 and the optimal p H for sporulation and spore germination were 8. 0 and 7. 0,respectively. Alternative light conditions were optimal for mycelial growth whereas complete light conditions were optimal for sporulation and spore germination. Spores germinated most rapidly at 95% relative humidity or in water-drop conditions,and failed germinate at relative humidity levels below 75%. Dextrose peptone medium was the best medium for mycelial growth and spore germination and potato dextrose agar was the best medium for sporulation. The best carbon source for mycelial growth and spore germination was glucose and that for sporulation was sucrose. The best nitrogen source for mycelium growth was peptone and that for spore germination and sporulation was yeast extract. The lethal temperature for mycelia was 54℃( 10 min) and that for spores was 48℃( 10 min). Based on these biological characteristics and the results of an ITS sequence analysis,the isolate was identified as Fusarium sporotrichioide.