Biocontrol effects of Brevibacillus laterosporus AMCC100017 on potato common scab and its impact on rhizosphere bacterial communities

Abstract

Potato common scab (PCS) is an economically important disease caused by Streptomyces spp. which occurs in potato planting areas worldwide. In this paper, pot experiments were conducted in the greenhouse to evaluate the biocontrol effects of Brevibacillus laterosporus AMCC100017 on potato common scab, and to assess the impact of the biocontrol bacterium on soil bacterial communities at four plant growth stages of potato. Results revealed that B. laterosporus AMCC100017 colonized steadily in potato rhizosphere ranging from 5.47 to 6.87 Log10 CFU g−1 soil detected by real-time PCR. It significantly (P<0.05) reduced the pathogen population of Streptomyces bottropensis from 4.54 to 4.28 Log10 CFU g−1 soil in the harvesting stage of potato, decreased the disease severity from 2.60 down to 0.77, and the biocontrol efficacy against common scab reached as great as 70.51%. Meanwhile, the relationship between B. laterosporus AMCC100017 and the functional microorganisms such as actinomycetes, Bacillus spp. and Pseudomonas spp. in the rhizosphere of potato, was discussed based on cultural method and the analyses of terminal restriction fragment length polymorphism (T-RFLP). The adding of B. laterosporus AMCC100017 had only slight transient impact on the native bacteria community in the flowering stage of potato. B. laterosporus AMCC100017 has the promising perspective developing into a biocontrol agent against potato common scab in the field.