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

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.