津黑两地大白菜褐腐病病原菌鉴定及生物学特性的比较

Identification and comparison of the biological characteristics of the pathogen causing brown rot of Chinese cabbage in Tianjin and Heilongjiang

采用形态特征观察、致病性测定及rDNA-ITS序列分析等方法对天津、黑龙江两地大白菜褐腐病的病原菌进行鉴定。结果表明,天津、黑龙江两地大白菜褐腐病的病原菌为立枯丝核菌(Rhizoctonia solani Kühn),分离鉴定出TJ和DB两个菌株,分属立枯丝核菌AG-2融合群和AG-1融合群;DB菌株为一新菌株。两菌株菌丝生长最适温度均为25℃,最适pH为7,最适光照为12h。DB菌株菌丝生长速率快于TJ菌株;但TJ菌株先于DB菌株形成菌核,且形成量多。两菌株在碳源、氮源利用和菌核致死温度上也存在差异。

The pathogen of Chinese cabbage brown rot was studied through morphological characteristics, patho- genicity, and ribosomal DNA-ITS sequence. The results showed that the two strains from Chinese cabbage brown rot collected from Tianjin and Heilongjiang were Rhizoctonia solani K/ihn TJ and DB, belonging to anastomosis group AG-2 and anastomosis group AG-1. The DB strain was a new strain. The optimal temperature, pH and illu- mination for mycelial growth of the two strains were 25 ℃, 7 and 12 h, respectively. The mycelial growth rate of the TJ strain was lower than the DB strain. The quantity and rate of sclerotia formation of the TJ strain were greater. There were obvious differences in the use of carbon sources, nitrogen sources and lethal temperature in the two strains.