Bacillus velezensis WSW007 Different Concentrations Volatile Organic Compounds Stimulated Tobacco Growth by Up-regulating the Expression of Genes Related to Plant Growth and Development

Abstract

Abstract Background and aims In order to investigate the mechanism of plant growth promoting (PGP) effects of strain Bacillus velezensisWSW007, its PGP traits including indoleacetic acid production, siderophore production, phosphate solubilization and production of volatile organic compounds (VOCs) were tested. Methods The effects of VOCs produced by strain WSW007 on plant growth were observed by co-culturing this strain with tobacco seedlings in I-plates. Meanwhile, the effects of VOCs on tobacco gene expression were estimated by a transcriptome analysis and VOCs were identified by solid phase micro extraction (SPME) method. Results Positive reactions for the tested three PGP traits were detected in culture of strain WSW007; while tobacco seedlings co-cultured with strain WSW007 increased the fresh weight up to 143% compared with that of control plants, demonstrating that VOCs production was also a PGP trait. In transcriptome analysis, plants co-cultured with strain WSW007 presented the highest up-regulated expression for the genes involved in plant growth and development processes, implying that the bacterial VOCs played a role as regulator of plant gene expression. It was expected the strain WSW007 has capacity of plant growth promotion, might because affection of two volatiles that 2,3-butanediol and acetoin. Conclusion The up-regulation in expression of growth- and development-related genes via VOCsproduction is an important PGP mechanism in strain WSW007. In future study, other volatile compounds produced by strain WSW007 should be examined and revealled the effects of VOCs.