对黄瓜枯萎病具防效的海洋源芽孢杆菌Y3F的鉴定

【目的】对一株从连云港海域海藻样品中获得的拮抗细菌Y3F进行鉴定并且研究菌株Y3F对黄瓜土传枯萎病害的控制效果。【方法】对Y3F进行形态、生理生化特征和16S r RNA基因序列分析,采用平板对峙法测定菌株Y3F的活菌液和无菌滤液的抑菌活性,利用盆栽试验测定Y3F对黄瓜枯萎病害的防治效果。【结果】初步鉴定该菌属于蜡样芽孢杆菌(Bacillus cereus),用2216E培养基振荡培养24 h的Y3F的无菌滤液对黄瓜尖孢镰刀菌有较强的抑菌活性,表明菌株能分泌抑制病原菌生长的活性物质。盆栽试验表明,种植30 d后,浸种和灌根同时处理(JG)的防治效果达到50.46%,对黄瓜枯萎病害有明显的控制效果,显著提高黄瓜植株生物量,显著降低黄瓜根际土的真菌和尖孢镰刀菌数量,增加根际的细菌和放线菌数量。【结论】菌株Y3F能有效防治黄瓜枯萎病害,改善根际微生物结构,具有进一步开发应用的前景。

Identification of marine bacillus isolate Y3F suppressing fusarium wilt of cucumber

[Objective] An antagonistic bacterium Y3F is isolated from marine algae in Lianyungang, its biocontrol effect on cucumber fusarium wilt is studied. [Methods] Y3F is identified as Bacillus cereus through the morphological, physiological and biochemical characteristics and phylogenetic analysis based on 16S rRNA gene sequence. The antimicrobial activity of broth and sterile filtrate of Y3F is checked by plate confrontation method, and its biocontrol activity to fusarium wilt of cucumber is checked by pot experiments. [Results] Y3F is identified as a member of Bacillus cereus. The sterile culture filtrate of Y3F in 2216E medium strongly inhibit the growth of Fusarium oxysporum strain cfcc 82185, implying that Y3F might secrete some kinds antifungal substances. The results of pot experiments indicated that soaking seeds and irrigating roots treatment (JG) could significantly increase the production of cucumber biomass, lower the incidence rate of fusarium wilt disease up to 50.46% after planting 30 days, and increase the total number of bacteria and actinomycetes, and decrease the number of fungi and Fusarium oxysporum strain cfcc 82185 in rhizosphere soil. [Conclusion] Strain Y3F can effectively control fusarium wilt of cucumber and improve microbial community structure in rhizosphere, and it has potential development and application prospect.