AUTHOR=Li Huixiu , Cai Xiaoxu , Gong Jingyang , Xu Ting , Ding Guo-chun , Li Ji 

TITLE=Long-Term Organic Farming Manipulated Rhizospheric Microbiome and Bacillus Antagonism Against Pepper Blight (Phytophthora capsici)

JOURNAL=Frontiers in Microbiology

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2019.00342

DOI=10.3389/fmicb.2019.00342

ISSN=1664-302X

ABSTRACT=<p>Soil-borne diseases are often less severe in organic farms, possibly because of the recruitment of beneficial microorganisms by crops. Here, the suppressiveness of organic, integrated, and conventionally managed soils to pepper blight (<italic>Phytophthora capsici</italic>) was studied in growth chamber experiments. Disease incidence was 41.3 and 34.1% lower in the soil from an organic farming system than in either the soil from the integrated or from the conventional farming systems, respectively. Beta-diversity of rhizospheric microbial communities differed among treatments, with enrichment of <italic>Bacillus, Sporosarcina</italic>, Acidobacteria <italic>Gp5, Gp6</italic>, <italic>Gp22</italic>, and <italic>Ignavibacterium</italic> by the organic soil. Cultivation-dependent analysis indicated that 50.3% of <italic>in vitro</italic> antagonists of <italic>P. capsici</italic> isolated from the rhizosphere of healthy peppers were affiliated to <italic>Bacillus</italic>. An integration of <italic>in vitro</italic> antagonists and bacterial diversity analyses indicated that <italic>Bacillus</italic> antagonists were higher in the rhizosphere of pepper treated by the organic soil. A microbial consortium of 18 <italic>in vitro Bacillus</italic> antagonists significantly increased the suppressiveness of soil from the integrated farming system against pepper blight. Overall, the soil microbiome under the long-term organic farming system was more suppressive to pepper blight, possibly owing to <italic>Bacillus</italic> antagonism in the rhizosphere. This study provided insights into microbiome management for disease suppression under greenhouse conditions.</p>