苏铁叶枯病病原菌鉴定

Identification of Leaf Blight Pathogen on Cycas revoluta Thunb

近年在贵州省苏铁各栽培地发现一种叶枯病害,为明确其致病菌,采集苏铁叶枯病叶片样本数份,并对病原菌进行形态观察、致病性测定及r DNA-ITS序列分析。结果表明:经分离纯化获得的病原菌,通过柯赫氏法则,接种后出现的病害症状与直接采集到的病害标样症状一致,确定其为致病菌;对病原菌进行传统的形态学观察,结果显示病原菌分生孢子器和分生孢子的形态与拟茎点霉一致;将待测菌株r DNA-ITS序列与Gen Bank中相关菌株ITS序列进行同源性比较,结果显示该菌株与Phomopsis vaccinii(Gen Bank登陆号为:KC488259,JX846914)的同源性达97%。结合病原菌形态学特征及株r DNA-ITS序列(Gen Ban登录号:JN417709)特征,确定苏铁叶枯病病原菌为Phomopsis cycadis.

Leaf blight on Cycas revoluta Thunb was discovered in Guizhou Province recently.The objective of the study was to identify the pathogen.The Cycas Leaf blight standard samples were collected and the pathogen was identified by morphology,pathogenicity and ribosomal DNA-ITS.The results showed that the isolated fungus was used for department＇ s law of disease and syndrome.Disease symptoms after inoculation were the same as that on the collected samples,which showed the fungus was the pathogen.The pycnidia and conidia＇ morphology of the pathogen were similar to that of Phomopsis.Comparing the measured sequence with the related sequence of Phomopsis vaccinii（No： KC488259,JX846914） in Gen Bank,the homology was 97%.According to its characteristics of morphology and sequence analysis of the internal transcribed spacer region of the ribosomal DNA（ITS）（No：JN417709）the pathogen was identified as Phomopsis cycadis.