广西崇左市甘蔗梢腐病病原菌的分离鉴定及生物学特性测定

Isolation identification and biological characteristics of the pathogen causing sugarcane pokkah boeng in Chongzuo,Guangxi

【目的】明确广西崇左市甘蔗梢腐病病原菌种类及其生物学特性,为甘蔗梢腐病的综合防治提供理论依据。【方法】以采集自广西崇左市甘蔗种植区的甘蔗梢腐病病叶为材料,采用组织分离法进行病原菌单孢分离,结合科赫法则进行致病性测定,通过形态学特征观察及rDNA-ITS序列分析对病原菌进行种类鉴定;应用十字交叉法进行病原菌的生物学特性测定。【结果】分离获得的病原菌rDNA-ITS序列长度为496 bp,与轮枝镰刀菌(Fusarium verticillioides)的同源性达99%,与轮枝镰刀菌(登录号EU047)的遗传关系最近。病原菌的生物学特性测定结果表明,该菌菌丝最适生长温度为28℃,致死温度为70℃;菌丝生长最适pH为8,光暗交替条件下生长较快;菌丝生长最适氮源为胰蛋白胨,最适碳源为甘露醇。【结论】引起广西崇左市甘蔗梢腐病的病原菌是轮枝镰刀菌,该菌适宜在高温高湿、弱碱性、光暗交替及富含有机营养的环境条件下生长。

【Objective】The present experiment was conducted to investigate species and biological characteristics of the pathogen causing sugarcane pokkah boeng in Chongzuo,Guangxi in order to provide scientific basis for controlling sugarcane pokkah boeng.【Method】Sugarcane leaves with sugarcane pokkah boeng in Chongzuo sugarcane planting areas were collected. Conventional tissue separation was applied to isolate monospore from the pathogen,and the pathogenicity of the pathogen were investigated. Based on morphological characteristics observation and analysis of rDNA-ITS sequence, the pathogen of sugarcane pokkah boeng was identified. Biological characteristics of the pathogen were determined with crossing methods.【Result】The rDNA-ITS sequence of tested strains was 496 bp in length,which showed 99% homology with Fusarium verticillioides. It had the closest genetic relationship with Fusarium verticillioides(accession number EU047). According to the biological characteristics test,the pathogen could grow with an optimal condition at 28 ℃,and the lethal temperature was 70 ℃. The best cultural condition for mycelial growth was pH 8,12 h dark+12 h light. The best nitrogen sources for the pathogen growth was tryptone,and the best carbon sources was mannito.【Conclusion 】The pathogen causing sugarcane pokkah boeng in Chongzuo is identified as F. verticillioides. The optimal growth conditions for F. verticillioides is high temperature,high humidity,weak alkaline,alternating light and dark and full of organic nutrition.