Listening to bacterial Esperanto: transcriptome reprogramming in a plant beneficial rhizobacterium

Abstract

Intraspecies, interspecies and interkingdom signalling occurring via diffusible communication signals (DCSs) continuously shapes the gene expression patterns of individual bacterial species in the rhizosphere, affecting bacterial functions within the rhizosphere microbial community. To unravel how DCSs influence rhizosphere competence of plant beneficial rhizobacteria, we carried out a functional and transcriptome analysis on the plant beneficial bacterium Lysobacter capsici AZ78 (AZ78). Results reveal that 13-methyltetradecanoic acid and indole, glyoxylic acid and 2,3-butanedione play a relevant role in the interaction between L. capsici members and other soil-living (micro)organisms. DCSs regulated mechanisms of multistress and multidrug tolerance and persistence, including detoxification, motility, antibiotic production, and expression of secretion systems. In particular, 13-methyltetradecanoic acid, glyoxylic acid and 2,3-butanedione might enable AZ78 to rapidly colonize the rhizosphere. Moreover, glyoxylic acid and 2,3-butanedione elicit biological responses to outcompete other (micro)organisms. In contrast, indole inactivates twitching motility and antibiotic production. These results demonstrate that DCSs influence the functioning of plant beneficial rhizobacteria and suggest that plant beneficial L. capsici strains could use them to foster rhizosphere colonization and enhance in vivo activities to increase soil health and plant fitness.