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旨在筛选出能高效抑制西瓜枯萎病病原菌尖孢镰刀菌(Fusarium oxysporum f.sp.niveum)的天然拮抗菌。采用梯度稀释法分离连作辣椒根际土中的放线菌,纯化后用平板对峙法筛选出有拮抗作用的菌株,采用盆钵育苗基质拌菌法接种,进行盆栽抗病试验,并对拮抗效果最佳的菌株进行鉴定。结果显示,从连作辣椒根际土中,分离筛选出10株对西瓜枯萎病有拮抗作用的放线菌,其中菌株F22、F23、F32的拮抗作用显著。96 h抑菌圈直径分别达到1.70、1.17和1.47 cm。盆栽试验结果表明,拮抗菌株F32对西瓜枯萎病30 d的防治效果最佳,防效率达到66.7%,且抗菌谱性广。根据表型特征、生理生化特性和16S r DNA分子鉴定结果可知,菌株F32为链霉菌属(Streptomyces sp.),且对西瓜枯萎病有良好的防治作用,是一株具有应用价值的生防菌株。
The aim of this study is to screen out natural antagonistic bacteria that can effectively inhibit Fusarium oxysporum f.sp.niveum, a pathogen of watermelon wilt disease. Gradient dilution method was used to separate the actinomycetes in the rhizosphere soil of pepper. After purification, strains with antagonistic activity were screened by plate confrontation method. The pots were inoculated with potting seedlings and mixed with bacteria to test their disease resistance. The antagonistic effects The best strains were identified. The results showed that 10 strains of actinomycetes that antagonized watery fusarium wilt were isolated and screened from rhizosphere soil of continuous cropped pepper. The antagonistic effects of strains F22, F23 and F32 were obvious. 96 h inhibition zone diameter reached 1.70,1.17 and 1.47 cm. The results of pot experiment showed that the antagonistic strain F32 had the best control effect on watermelon blight for 30 d, its anti-efficiency was 66.7%, and its antibacterial spectrum was wide. According to phenotypic characteristics, physiological and biochemical characteristics and 16S r DNA molecular identification results, it can be seen that strain F32 is a Streptomyces sp. And has good control effect on watermelon blight and is a biocontrol strain with application value .