Transcriptome Analysis of Biocontrol Strain Bacillus subtilis Pro-2 and Its Mutants

Abstract

To enhance the antagonistic ability against tobacco bacterial wilt, physical mutagenesis was in this study induced using nitrogen ion beam irradiation, and resulting mutant strain K60 of Bacillus subtilis Pro-2 effectively controlled Ralstonia solanacearum. Through transcriptome sequencing, a total of 1291 significantly different genes were screened, including 424 up-regulated genes and 867 down-regulated genes. After enrichment by GO and KEGG metabolic pathways, there were more differential genes enriched in lipopeptide metabolic pathways. The analysis of significantly changed differential genes showed that, among the three common lipopeptide antibacterial substances of Bacillus (surfactin, iturin and fengycin), the synthetic surfactin genes were significantly increased (P ≤ 0.01). According to transcriptome data, the srfA gene, which is related to surfactin synthetase, had very significant change in transcription (P ≤ 0.01), and transcription of two regulatory factors (Rap, CodY) related to srfA gene expression were reduced, with CodY being significantly downregulated at the transcription level.