甜瓜镰刀菌果腐病新病原菌Fusarium incarnatum的鉴定及生物学特性

采用常规组织分离法对采自山西省太谷县疑似镰孢刀菌引起的甜瓜果实新病害进行病原菌分离,根据柯赫氏法则明确其致病性。基于形态特征以及核糖体内转录间隔区(rDNA-ITS)、转录延伸因子(EF-1α)、组蛋白(Histone 3)和线粒体中核糖体小亚基(mtSSU)序列分析,鉴定该病原菌为变红镰刀菌(Fusarium incarnatum)。病原菌的生物学特性测定结果表明,菌丝生长和产孢最适培养基均为马铃薯蔗糖琼脂培养基(PSA);温度为20～35℃菌丝生长较快,20～25℃产孢量最大;羧甲基纤维素钠、淀粉和木糖等碳源适合菌丝生长,产孢的最佳碳源为乳糖;病原菌在多种氮源上均能较好生长,产孢的最佳氮源为酵母粉;pH为8时菌丝生长最快,不同pH处理的产孢量间差异不显著;病原菌在全光照和全黑暗条件下能较好生长,不同光照条件下产孢量差异不显著;菌丝致死温度为61℃(10min),分生孢子致死温度为56℃(10 min)。

Identification and Biological Characteristics of a Novel Pathogen Fusarium incarnatum Causing Muskmelon Fruit Fusarium Rot

A novel disease of suspected Fusarium fruit rot was observed on muskmelon in Taigu County，Shanxi Province. The isolate was obtained from diseased sample by conventional tissue isolation method. The pathogenicity was confirmed by Koch’s postulates. The pathogen was identified as Fusarium incarnatum based on morphological characteristics and the sequence analysis of rDNA-ITS，EF-1α，histone 3 and mtSSU. The results of biological characteristics showed that PSA medium was most conducive to mycelium growth and sporulation；the ideal temperature conditions for mycelium growth and sporulation were in the range of 20–35 ℃ and 20–25 ℃，respectively；the suitable carbon sources for mycelium growth were CMC-Na，starch and xylose，the optimal carbon source for sporulation was lactose. The pathogen could grow fastly on the medium with kinds of nitrogen sources，the optimal nitrogen source for sporulation was yeast powder. The optimal pH for mycelium growth was 8. The full illumination and full darkness was suitable for mycelium growth. The sporulation under pH and light conditions had not significant difference. The mycelial lethal temperature was at 61 ℃ for 10 min，and the spore lethal temperature was at 56 ℃ for 10 min.