甜瓜蔓枯病病原鉴定及其生物学特性

Identification of Muskmelon Gummy Stem Blight Pathogen and Its Biological Characters

从江苏省部分地区感染蔓枯病的甜瓜茎上分离病原菌,并对其形态学、生物学特性及致病力进行了研究。结果表明,共分离得到4株甜瓜蔓枯病菌株,这4株病菌的最适生长温度为25℃,培养基pH值对病菌生长的影响不大。另外,对这4个菌株的核糖体RNA基因内转录间隔区(rDNA-ITS)进行了PCR扩增和序列测定,并在GenBank中进行了Blast搜索和比对分析,根据rDNA-ITS序列分析结果结合甜瓜病株症状和病菌的形态学特征,初步认为江苏省甜瓜蔓枯病的病原菌为Didymella bryoniae(Auersw.)Rehm.,其无性型为西瓜壳二孢Ascochyta citrullinaSmith.

Gummy stem blight is an important disease of muskmelon in the middle and later growth season. The affected stems of muskmelon were collected from some areas of Jiangsu province, China, and four strains of the pathogenic fungi isolated from the sample stems were investigated for the morphological and biological characters. The optimal temperature for the fungal growth was 25 ℃, and there were no significant effects of the pH value in the media on the growth of the pathogen. The rDNA-ITS genes of 4 isolates were amplified and sequenced. Based on the Blast search and the alignment analysis in GenBank database combined morphological characters, the pathogen of muskmelon gummy stem blight was identified as Didymella bryoniae （ Auersw. ） Rehm. , anamorph being Ascochyta citrullina Smith.