GSE184428
RdsA is a global regulator that controls cell shape and division in Rhizobium etli
Unlike other bacteria, cell growth in rhizobiales is unipolar and asymmetric. The regulation of cell division, and its coordination with metabolic processes is an active field of research. In Rhizobium etli, gene RHE_PE00024, located in a secondary chromosome, is essential for growth. This gene encodes a hybrid histidine kinase sensor protein, participating in a, as yet undescribed, two-component signaling system. In this work, we show that a conditional knockdown mutant (cKD24) in RHE_PE00024 (hereby referred as rdsA, after rhizobium division and shape) generates a striking phenotype, characterized by cells with a round shape, with stochastic and uncoordinated cell division. A fraction of the cells showed also multiple ectopic polar growths, sometimes leading to growth from the old pole, a sector that is normally inactive for growth in a wild-type cell. Homodimerization of RdsA appears to be required for normal function. RNAseq analysis of mutant cKD24 reveals global changes, with differentially expressed genes in at least five biological processes: cell division, wall biogenesis, respiration, translation, and motility. These modifications may affect proper structuring of the divisome, as well as peptidoglycan synthesis. Together, these results indicate that the hybrid histidine kinase RdsA is an essential global regulator influencing cell division and cell shape in R. etli. Overall design: Differential expression profiling of genes associated with RdsA depletion (strain cKD24). Control strain: R etli CE3 wild-type. Strains were grown in Y minimal medium for 9 h at 30°C. Three biological replicates for each strain.