黄瓜枯萎病拮抗芽孢杆菌的筛选、鉴定及其生防潜力

Screening and Identification of Antagonistic Bacillus spp.Against Cucumber Fusarium wilt and Its Biocontrol Effect

尖镰孢菌黄瓜专化型(Fusarium oxysporum f.sp.cucumerinum)引起的枯萎病严重影响黄瓜产业可持续发展,为获得高效拮抗黄瓜枯萎病的芽孢杆菌并明确其促生效果,从具有一定抗性的芽孢杆菌中,筛选出高抗尖镰孢菌的生防菌株,并对其进行形态、生理生化、遗传特性及植株促生特性的评价。结果表明,菌株N1、N3和N6抑制尖镰孢菌效果显著,抑菌率分别为77.71%、75.94%、74.76%。鉴定3个菌株均为贝莱斯芽孢杆菌(Bacillus velezensis),且具解钾、分泌蛋白酶、几丁质酶、果胶酶和产铁载体的能力。黄瓜幼苗防病促生盆栽试验表明,接种菌株N1、N3和N6病情指数均显著降低,在接种18 d后防病效果分别为41.93%、20.97%、66.13%。与单一接种病原菌处理相比,N1、N3和N6接种显著促进了黄瓜幼苗生长,包括株高、茎粗、叶面积、叶绿素含量、地上和地下部鲜重,其中N6处理增加效果最显著,分别增加21.56%、56.13%、47.95%、76.18%、229.89%、70%。与对照相比,处理植株长势特性除地下部鲜重外均显著降低;病原菌接种条件下,添加N6菌显著增加茎粗和地上部鲜重。N6可作为防控黄瓜枯萎病、促进幼苗生长有潜力的生物防治资源,用于黄瓜可持续高效生产。

Cucumber Fusarium wilt caused by Fusarium oxysporum f.sp.cucumerinum seriously affects the sustainable development of the cucumber industry.In order to obtain high-efficiency antagonistic Bacillus spp.against cucumber Fusarium wilt and clarify its growthpromoting effect,hte biocontrol strain with a strong antagonistic effect against F.oxysporum were screened from Bacillus with a certain resistance to Fusarium solan,and its morphological,physiological and biochemical,genetic characteristics and plant growth-promoting characteristics were evaluated.The results showed that strain N1、N3 and N6 presented significant inhibitory effects on F.oxysporum,with inhibitory rates of 77.71%,75.94%and 74.76%,respectively.Three strains were all identified as Bacillus velezensis,all the three strains showed releasing potassium ability,and produced protease,chitinase,pectinase and siderophores.In the seedlings disease-prevention and growth-promotion test,the disease index of inoculated strain N1,N3 and N6 significantly reduced,the control efficiency was 41.93%,20.97%,and 66.13%respectively on the 18th day after inoculation.Inoculation with N1,N3 and N6 strains effectively promoted the growths of cucumber seedlings compared with single inoculation of F.oxysporum f.sp.treatment,including plant height,stem thickness,leaf area,chlorophyll content and aboveground and subsurface fresh weight,the growth promoting effect of N6 treatment was the most significant.It increased by 21.56%,56.13%,47.95%,76.18%,222.89%and 70%respectively.Compared with the control,the growth characteristics of treated plants significantly decreased except for the fresh weight of underground parts.Under inoculation F.oxysporum f.sp.,the addition of N6 significantly increased the stem thickness and aboveground fresh weight.In conclusion,N6 can be used as potential biocontrol resources to control cucumber Fusarium wilt caused by F.oxysporum f.sp.cucumerinum and promote the growth of seedlings for sustainable and efficient cucumber production.