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Knockout of rapC improves bacillomycin D yield based on de novo genome sequencing of Bacillus amyloliquefaciens fmbJ.

Research paper by Jing J Sun, Shiquan S Qian, Jing J Lu, Yanan Y Liu, Fengxia F Lu, Xiaomei X Bie, Zhaoxin Z Lu

Indexed on: 13 Apr '18Published on: 13 Apr '18Published in: Journal of Agricultural and Food Chemistry



Abstract

Bacillus amyloliquefaciens, a gram-positive and soil-dwelling bacterium, could produce secondary metabolites that suppress plant pathogens. In this study, we provided the whole genome sequence results of B. amyloliquefaciens fmbJ which had one circular chromosome of 4,193,344 bp with 4,249 genes, 87 transfer RNA genes, and 27 rRNA genes. In addition, fmbJ was found to contain several gene clusters of antimicrobial lipopeptides (bacillomycin D, surfactin, and fengycin) and bacillomycin D homologues were further comprehensively identified. To clarify the influence of rapC regulating the synthesis of lipopeptide on the yield of bacillomycin D, rapC gene in fmbJ was successfully deleted by marker-free method. Finally, it was found that the deletion of rapC gene in fmbJ significantly improved bacillomycin D production from 240.7 ± 18.9 mg/L to 360.8 ± 30.7 mg/L, attributed to the increased the expression of bacillomycin D synthesis-related genes through enhancing the transcriptional level of comA, comP, and phrC. These results showed that the production of bacillomycin D in B. amyloliquefaciens fmbJ might be regulated by the RapC-PhrC system. The findings are expected to advance further agricultural application of bacillus spp. as a promising source of natural bioactive compounds.