Potential of endophytic bacteria isolated from Sophora alopecuroides nodule in biological control against Verticillium wilt disease

Abstract

Antagonistic activities against Verticillium dahliaewere screened in sixty endophytic bacteria isolated from root nodules of Sophora alopecuroides by plate spreading, plate confrontational cultureand examining the antifungal activity of extracellular products methods. The results showed that inhibitory rate of more than half of the 60 studied strains is 50%, fungistasis zone of 41 strains is beyond 15 mm and those of 36 strains is over 5 mm, respectively, through the above-mentioned method. In addition, 17 strains showed remarkable seed germination-promoting activity. Mean control effect of strains Bacillus subtilis KDRE01 and Bacillus megateriumKDRE25 in the prevention against cotton Verticillium wilt under pot-growing conditions was 84.91% and 78.82%, respectively, and showed significant difference(p<0.05) from the CK1 and CK2. Moreover, these two strains showed plant growth promoting characteristics (such as IAA and ACC deaminase activity, etc.) and both exhibited obvious promoting effects(p<0.05)on cotton growth. These results suggested that the nodule endophytic bacteria of S. alopecuroides were valuable biological resources, which might be potential biocontrol agents.