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对北京地区大白菜发生的叶片黄化、维管束变色的新病害进行了鉴定,通过形态学观察、致病力检测和rDNA-ITS序列分析,确定该病是由大丽轮枝菌(Verticilliumdahliae)引起的大白菜黄萎病。从4个发病大白菜材料中分离获得的4个真菌分离物,均在寄主大白菜三叶一心期接种后表现出叶片黄化、维管束变色等症状;PDA培养菌落为白色,1周后中心变黑,显微镜下可观察到明显的轮枝状分生孢子梗,长椭圆形孢子大小3.5~5.6μm×1.5~2.5μm,在22℃菌丝生长最快。4个菌株的rDNA-ITS序列一致性达100%,序列已在GenBank上登录,登录号为JN564038。
The new diseases of leaf yellowing and vascular discoloration in Chinese cabbage in Beijing were identified. Morphological observation, pathogenicity test and rDNA-ITS sequence analysis indicated that the disease was caused by Verticillium dahliae, Caused cabbage Verticillium wilt. Four fungal isolates isolated from four Chinese cabbage cultivars showed yellowing and vascular discoloration after single-stage inoculation of host Chinese cabbage. PDA culture colonies were white and after 1 week, Black and obvious round branch conidiophores were observed under microscope. The size of long oval spores was 3.5-5.6μm × 1.5-2.5μm, and mycelial growth was the fastest at 22 ℃. The rDNA-ITS sequences of the four strains were 100% identical, and the sequences were registered in GenBank with accession number JN564038.