江西瑞昌山药炭疽病菌的形态及分子鉴定

Morphological and Molecular Identification of Pathogen of Yam Anthracnose in Ruichang City,Jiangxi Province

为了明确江西瑞昌山药炭疽病病原菌种类归属,本文从当地采集呈典型症状的炭疽病叶片进行了病原菌分离鉴定。通过组织分离获得8个在培养性状和分生孢子形态大小均一致且均具有致病性的分离株,8个分离株在PDA平板上菌落初为白色,后变为灰色至深灰色,菌落中央产生橘红色黏质分生孢子团。分生孢子无色,长椭圆形至纺锤形,单胞,大小为(15.6~18.0)μm×(3.6~6.0)μm。对其中之一的分离株YRRC-1进行rDNA-ITS区段扩增和序列测定,获得长度为536 bp的rDNA-ITS序列,该序列与胶孢炭疽菌(Colletotrichum gloeosporioides)的对应序列同源性达100%。根据分离病菌的培养特征、形态大小和序列鉴定结果,认为瑞昌山药炭疽病菌属于胶孢炭疽菌(C.gloeosporioides)。

To ascertain which species of Colletotrichum resulted in yam anthracnose in Ruichang City,Jiangxi Province,the diseased leaf samples were collected and the pathogenic fungi were identified.Eight Colletotrichum isolates with identical characteristics in cultivation and morphology of conidia were obtained by using tissue separating method,and they were all proved to have been pathogenic to yam.White colony was formed on PDA medium in the early stage of cultivation for each of eight isolates.It then turned to be from grey to dark grey,and produced orange sticky conidial masses in the colonial center.The conidia of each of these eight isolates were colorless,long elliptical or spindly,single cell,and 15.6~18.0×3.6~6.0?m in size.rDNA-ITS region of YRRC-1(one of the eight isolates) was amplified by PCR,and the 536bp sequence was determined.100% homology of rDNA-ITS sequence between YRRC-1 and Colletotrichum gloeosporioides was found.Based on results of cultural characteristics,conidial morphology and size,as well as rDNA-ITS sequence of the fungus,the pathogen of yam anthracnose in Ruichang City,Jiangxi Province,was identified as Colletotrichum gloeosporioides.