AUTHOR=Hu Yuanliang , Qiu Lu , Zhang Zongjie , Liu Kai , Xia Xian , Xiong Shuanglian , Zhao Shumiao , Zhao Zhuqing , Hu Yongmei , Liang Yunxiang 

TITLE=Control of Streptomyces alfalfae XY25T Over Clubroot Disease and Its Effect on Rhizosphere Microbial Community in Chinese Cabbage Field Trials

JOURNAL=Frontiers in Microbiology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.641556

DOI=10.3389/fmicb.2021.641556

ISSN=1664-302X

ABSTRACT=<p>Clubroot caused by <italic>Plasmodiophora brassicae</italic> is one of the most destructive diseases in cruciferous crops. <italic>Streptomyces alfalfae</italic> XY25<sup><italic>T</italic></sup>, a biological control agent, exhibited great ability to relieve clubroot disease, regulate rhizosphere bacterial and fungal communities in Chinese cabbage, and promote its growth in greenhouse. Therefore, field experiments were carried out to investigate the effects of <italic>S. alfalfae</italic> XY25<sup><italic>T</italic></sup> on clubroot and rhizosphere microbial community in Chinese cabbage. Results showed that the control efficiency of clubroot by <italic>S. alfalfae</italic> XY25<sup><italic>T</italic></sup> was 69.4%. Applying the agent can alleviate soil acidification; increase the contents of soil organic matter, available nitrogen, available phosphorus, and available potassium; and enhance activities of invertase, urease, catalase, and alkaline phosphatase. During Chinese cabbage growth, bacterial diversity decreased first and then increased, and fungal diversity decreased gradually after inoculation with <italic>S. alfalfae</italic> XY25<sup><italic>T</italic></sup>. High-throughput sequencing analysis showed that the main bacterial phyla were Proteobacteria, Bacteroidetes, Acidobacteria, and Planctomycetes, and the major fungal phyla were Ascomycota and Basidiomycota in rhizosphere soil. The dominant bacterial genera were <italic>Flavobacterium</italic>, <italic>Candidatus</italic>, <italic>Pseudomonas</italic>, <italic>Stenotrophomonas</italic>, <italic>Sphingomonas</italic>, <italic>Flavisolibacter</italic>, and <italic>Gemmatimonbacteria</italic> with no significant difference in abundance, and the major fungal genera were <italic>Monographella</italic>, <italic>Aspergillus</italic>, <italic>Hypocreales</italic>, <italic>Chytridiaceae</italic>, <italic>Fusarium</italic>, <italic>Pleosporales</italic>, <italic>Agaricales</italic>, <italic>Mortierella</italic>, and <italic>Pleosporales</italic>. The significant differences were observed among <italic>Pleosporales</italic>, <italic>Basidiomycota</italic>, <italic>Colletotrichum</italic>, two strains attributed to <italic>Agaricales</italic>, and another two unidentified fungi by using <italic>S. alfalfae</italic> XY25<sup><italic>T</italic></sup>. Moreover, quantitative real-time PCR results indicated that <italic>P. brassicae</italic> content was significantly decreased after the agent inoculation. In conclusion, <italic>S. alfalfae</italic> XY25<sup><italic>T</italic></sup> can affect rhizosphere microbial communities; therefore, applying the agent is an effective approach to reduce the damage caused by clubroot.</p>