Abstract:
Objective Utilizing the rich microbial resources in mangrove sediments, we screen for Bacillus strains with broad-spectrum antagonistic activity to provide support for the development of highly efficient and green biological control agents to combat important agricultural diseases such as fire blight.
Method Using the thermotolerant characteristic of Bacillus, we specifically screened Bacillus strains with antagonistic activity against Erwinia amylovora, the causal agent of fire blight. We also used the plate confrontation method to detect the antagonistic activity of these Bacillus strains against Xanthomonas oryzae pv. oryzae, Ralstonia solanacearum, Colletotrichum gloeosporioides and Fusarium graminearum, then focused on the control effect of these Bacillus strains against fire blight and strawberry anthracnose in greenhouse.
Result Ten Bacillus strains were selected for their antagonistic effects against E. amylovora. Among them, the three strains with the strongest antagonistic activity were PBIB1, PBIB4, and PBIB7. After genome sequencing, PBIB1 and PBIB4 were identified as B. velezensis,while PBIB7 was identified as B. subtilis. These three strains exhibited antagonistic activity against X. oryzae pv. oryzae, R. solanacearum, C. gloeosporioides and F. graminearum, and had efficacy of 82.83%, 78.84%, and 68.86% against fire blight, 92.31%, 90.38%, and 67.30% against strawberry anthracnose in greenhouse, respectively.
Conclusion Three biocontrol Bacillus strains are screened in the mangrove sediments in Fujian province, which have a broad-spectrum antagonistic effect on crop bacterial and fungal diseases, and have the potential for further development and application of biocontrol agents.
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