RNA-Seq gene expression profiling in the plant growth promoting Bacillus atrophaeus UCMB-5137 revealed an alternative strategy of plant colonization compared to Bacillus amyloliquefaciens endophytes. Bacillus atrophaeus

Plant growth promoting rhizobacteria (PGPR) of the genus Bacillus are successfully used as biofertilizers and biopesticides. They potentially can reduce the use of chemicals in agriculture as an ecologically safe alternative, but to optimize the application of PGPR, more profound knowledge on specific gene regulation and molecular mechanisms of interaction with plants is needed. Advance in sequencing technologies made it affordable to compare transcriptom profiles of relative organisms to check to which extend PGPR strains or closely related species differ in their strategies of plant colonization. This work aimed at analysis of gene regulation in a biotechnological strain Bacillus atrophaeus UCMB-5137 to compare it with the gene expression profile of a generally recognized PGPR strain B. amyloliquefaciens FZB42. It was found out that despite the close taxonomic relatedness, these two organisms developed ability to colonize plants independently and use different strategies of plant colonization. Root exudate has triggered in UCMB-5137 alteration in expression in many genes controlled by stress response transcription factors (TF) SigB and SigD, while SigF, SigH, SigW, CcpA and several other TFs regulated genes associated with quorum sensing and biofilm formation, and adjusted the carbohydrate metabolism. Counting to peculiarities of gene regulation in different PGPR strains will allow optimization of their practical application. Overall design: Examination of 2 experimental samples grown on liquid medium with maize root exudate and 3 control samples