甘肃省甜瓜黄萎病的病原鉴定

Verticillium wilt of melon caused by Verticillium dahliae in Gansu province, China

摘要:

【背景】2013年11月在甘肃省兰州市皋兰县的日光温室秋冬茬甜瓜种植棚发现黄萎症状的甜瓜植株，病株率约为1%。【目的】明确甜瓜黄萎病的病原。【方法】采用组织分离法进行病原菌分离；通过科赫氏法则(Koch’s法则)明确分出病菌的致病性；采用形态学和分子生物学方法对病原菌进行种类鉴定。【结果】分离得到轮枝菌属真菌8株，轮枝菌属真菌的病株分出率达100%；2个代表性菌株GLTG-2和GLTG-5 (显微特征相似但菌落形态和生长速率不同)，在温度18?24 °C及昼/夜光周期为11.5 h/12.5 h的试验条件下，人工接种可引起甜瓜苗矮化、枯萎；接种后40 d，枯死株率分别为70%和40%；BLASTn分析结果显示，菌株GLTG-2的rDNA-ITS序列与Verticillium dahliae菌株MRHf7的序列相似性达99.78%，菌株GLTG-5的rDNA-ITS序列与V. dahliae菌株MRHf7和Vd414的序列相似性达100.00%。【结论】引起甜瓜黄萎病的病原菌被鉴定为大丽轮枝菌(V. dahliae)，这是大丽轮枝菌引起甜瓜黄萎病在我国和亚洲地区的首次报道。

关键词:甜瓜，黄萎病，大丽轮枝菌，温度，光周期

Abstract:

[Background] In November 2013, verticillium wilt of melon was observed in greenhouse in Gaolan county, Lanzhou city, Gansu province and its incidence was about 1%. [Objective] The present study was to identify the pathogen of the melon disease. [Methods] Pathogen was isolated by diseased tissue isolation method. Koch’s procedures were used to verify the disease pathogen; morphological and molecular biological methods were used to identify the pathogen. [Results] Eight fungal isolates of Verticillium were isolated from diseased plant samples; the isolation rate was 100% in diseased plants. Under test conditions (temperature: 18?24 °C; photoperoid: day/night=11.5 h/12.5 h), artificial inoculation with two representative isolates GLGT-2 and GLGT-5 with similar in microscopic features, but different in colony morphology and growth rate, caused dwarfing and wilting on melon seedlings; the incidences of wilting plant were 70% and 40% respectively after 40 days inoculation; BLASTn analysis showed that the rDNA-ITS sequences of GLGT-2 had a 99.78% similarity with V. dahliae isolate MRHf7, and GLGT-5 had a 100.00% similarity with V. dahliae isolate MRHf7 and Vd414. [Conclusion] The isolates causing verticillium wilt on melon were both identified as V. dahliae by morphological and molecular biological identification. This is the first report of verticillium wilt of melon caused by V. dahliae in China and Asia.

Key words:Cucumis melo, Verticillium wilt, Verticillium dahliae, Temperature, Photoperoid