大豆疫霉病病菌生防放线菌的筛选、鉴定及生防效果

Screening,identification and biocontrol effect of actinomycetes against Phytophthora sojae

为了开发对大豆疫霉病病菌具有拮抗作用的放线菌资源,从健康大豆根际土壤中分离筛选获得2株对大豆疫病具有显著抑制效果的生防放线菌菌株JAX-13和JAX-14。经生理生化和分子生物学鉴定,菌株JAX-13和JAX-14分别为放线菌属细菌(Actinomycetales bacterium)和链霉菌(Streptomyces)。平板拮抗试验结果表明,2种菌株对大豆疫霉病病菌的抑制率分别为56.26%和50.06%;光学显微镜观察发现,菌株JAX-13和JAX-14发酵液处理的大豆疫霉病病菌菌丝排列杂乱无章,菌丝生长受到抑制并且菌丝内部出现原生质聚集成块现象。盆栽试验结果表明,经菌株JAX-13和JAX-14发酵液处理的大豆对大豆疫霉病病菌的防效分别达56.56%和72.22%,且菌株发酵液对大豆植株具有一定的促生作用。总体来看,菌株JAX-13和JAX-14生防效果优良,是2种具有潜在应用价值的放线菌。

To develop actinomycete resources with antagonistic effect on Phytophthora sojae,two strains of biocontrol actinomycetes JAX-13 and JAX-14 were isolated and screened from healthy soybean rhizosphere soil,which had significant inhibitory effect on soybean Phytophthora blight.Through physiological,biochemical analysis and molecular biology identification,strains JAX-13 and JAX-14 were identified as Actinomycetales bacterium and Streptomyces,respectively.The results of plate confrontation test showed that,the inhibition rates of two strains to P.sojae were 56.26%and 50.06%,respectively.Through optical microscope observation,it was found that the hyphae of P.sojae treated by the fermentation broth of JAX-13 and JAX-14 strains arranged disorderly,the growth of hyphae was inhibited and the protoplasm in hyphae gathered into lumps.The results of pot experiment showed that,after treated with fermentation broth of JAX-13 or JAX-14 strain,the control effects of soybeans against P.sojae were 56.56%and 72.22%,respectively,and the fermentation broth showed some promoting effects on the growth of soybean plants.In general,strains JAX-13 and JAX-14 are two kinds of actinomycete with good biocontrol effect and show potential application value.