Affiliation:
1. Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing 210037, China
2. College of Life Science, Nanjing Forestry University, Nanjing 210037, China
Abstract
Bacillus velezensis FZB42, a representative strain of plant-growth-promoting rhizobacteria (PGPR), can form robust biofilm and produce multiple antibiotics against a wild range of phytopathogens. In this study, we observed different biofilm morphology of the mutant Y4, derived from a TnYLB-1 transposon insertion library of B. velezensis FZB42. We identified that the transposon was inserted into the sprT gene in Y4. Our bioinformatics analysis revealed that the SprT protein is an unstable hydrophilic protein located in the cytoplasm. It is highly conserved in Bacillus species and predicted to function as a metalloprotease by binding zinc ions. We also demonstrated that ΔsprT significantly reduced the swarming ability of FZB42 by ~5-fold and sporulation capacity by ~25-fold. In addition, the antagonistic experiments showed that, compared to the wild type, the ΔsprT strain exhibited significantly reduced inhibition against Staphylococcus aureus ATCC-9144 and Phytophthora sojae, indicating that the inactivation of sprT led to decreased production of the antibiotic bacilysin. The HPLC-MS analysis confirmed that bacilysin was indeed decreased in the ΔsprT strain, and qPCR analysis revealed that ΔsprT down-regulated the expression of the genes for bacilysin biosynthesis. Our results suggest that the sprT gene plays a regulatory role in multiple characteristics of B. velezensis FZB42, including biofilm formation, swarming, sporulation, and antibiotic production.
Funder
National Natural Science Foundation of China
Subject
Inorganic Chemistry,Organic Chemistry,Physical and Theoretical Chemistry,Computer Science Applications,Spectroscopy,Molecular Biology,General Medicine,Catalysis
Reference38 articles.
1. Singla, J., and Krattinger, S.G. (2016). The Production and Genetics of Food Grains, Elsevier.
2. Han, X., Shen, D., Xiong, Q., Bao, B., Zhang, W., Dai, T., Zhao, Y., Borriss, R., and Fan, B. (2021). The Plant-Beneficial Rhizobacterium Bacillus velezensis FZB42 Controls the Soybean Pathogen Phytophthora sojae Due to Bacilysin Production. Appl. Environ. Microbiol., 87.
3. Structure and activity of proteins from pathogenic fungi Phytophthora eliciting necrosis and acquired resistance in tobacco;Ricci;Eur. J. Biochem.,1989
4. Cyclic Lipopeptides of Bacillus amyloliquefaciens subsp. plantarum Colonizing the Lettuce Rhizosphere Enhance Plant Defense Responses Toward the Bottom Rot Pathogen Rhizoctonia solani;Chowdhury;Mol. Plant-Microbe Interact.,2015
5. Gram-positive rhizobacterium Bacillus amyloliquefaciens FZB42 colonizes three types of plants in different patterns;Fan;J. Microbiol.,2012