Global transcriptome analysis of Rhizobium favelukesii LPU83 in response to acid stress

DRAGHI, WALTER O; WINKLER, ANIKA; PÜHLER, ALFRED; PISTORIO, MARIANO; NILSSON, JULIET F; MOGRO, EZEQUIEL G; HANSEN, L H; KALINOWSKI, JÖRN; CASTELLANI, LUCAS G; WIBBERG, DANIEL; SCHLÜTER, ANDREAS; TORRES TEJERIZO, GONZALO A

FEMS MICROBIOLOGY ECOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2020

0168-6496

Acidic environments naturally occur worldwide and inappropriate agricultural management may also cause acidification of soils. Low soil pH values are an important barrier in the plant-rhizobia interaction. Acidic conditions disturb the establishment of the efficient rhizobia usually used as biofertilizer. This negative effect on the rhizobia-legume symbiosis is mainly due to the low acid-tolerance of the bacteria. Here, we describe the identification of relevant factors in the acid tolerance of Rhizobium favelukesii using transcriptome sequencing. A total of 1,924 genes were differentially expressed under acidic conditions, with ca. 60% underexpressed. R. favelukesii acid response mainly includes changes in the energy metabolism and protein turnover, as well as a combination of mechanisms that may contribute to this phenotype, including GABA and histidine metabolism, cell envelope modifications and reverse proton efflux. We confirmed the acid-sensitive phenotype of a mutant in the braD gene, which showed higher expression under acid stress. Remarkably, 60% of the CDS encoded in the symbiotic plasmid were underexpressed and we evidenced that a strain cured for this plasmid featured an improved performance under acidic conditions. Hence, this work provides relevant information in the characterization of genes associated with tolerance or adaptation to acidic stress of R. favelukesii.