AUTHOR=Feng Zhibin , Xu Mingzhi , Yang Jin , Zhang Renhong , Geng Zigui , Mao Tingting , Sheng Yuting , Wang Limin , Zhang Juan , Zhang Hongxia 

TITLE=Molecular characterization of a novel strain of Bacillus halotolerans protecting wheat from sheath blight disease caused by Rhizoctonia solani Kühn

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.1019512

DOI=10.3389/fpls.2022.1019512

ISSN=1664-462X

ABSTRACT=<p><italic>Rhizoctonia solani Kühn</italic> naturally infects and causes Sheath blight disease in cereal crops such as wheat, rice and maize, leading to severe reduction in grain yield and quality. In this work, a new bacterial strain <italic>Bacillus halotolerans</italic> LDFZ001 showing efficient antagonistic activity against the pathogenic strain <italic>Rhizoctonia solani Kühn</italic> sh-1 was isolated. Antagonistic, phylogenetic and whole genome sequencing analyses demonstrate that <italic>Bacillus halotolerans</italic> LDFZ001 strongly suppressed the growth of <italic>Rhizoctonia solani Kühn</italic> sh-1, showed a close evolutionary relationship with <italic>B. halotolerans</italic> F41-3, and possessed a 3,965,118 bp circular chromosome. Bioinformatic analysis demonstrated that the genome of <italic>Bacillus halotolerans</italic> LDFZ001 contained ten secondary metabolite biosynthetic gene clusters (BGCs) encoding five non-ribosomal peptide synthases, two polyketide synthase, two terpene synthases and one bacteriocin synthase, and a new kijanimicin biosynthetic gene cluster which might be responsible for the biosynthesis of novel compounds. Gene-editing experiments revealed that functional expression of phosphopantetheinyl transferase (SFP) and major facilitator superfamily (MFS) transporter genes in <italic>Bacillus halotolerans</italic> LDFZ001 was essential for its antifungal activity against <italic>R. solani Kühn</italic> sh-1. Moreover, the existence of two identical chitosanases may also make contribution to the antipathogen activity of <italic>Bacillus halotolerans</italic> LDFZ001. Our findings will provide fundamental information for the identification and isolation of new sheath blight resistant genes and bacterial strains which have a great potential to be used for the production of bacterial control agents.</p><sec><title>Importance</title><p>A new <italic>Bacillus halotolerans</italic> strain <italic>Bacillus halotolerans</italic> LDFZ001 resistant to sheath blight in wheat is isolated. <italic>Bacillus halotolerans</italic> LDFZ001 harbors a new kijanimicin biosynthetic gene cluster, and the functional expression of <italic>SFP</italic> and <italic>MFS</italic> contribute to its antipathogen ability.</p></sec>