A Novel Regulatory Pathway for K Uptake in the Legume Symbiont Azorhizobium caulinodans in Which TrkJ Represses the Operon at High Extracellular K Concentrations.

Bacteria have multiple K uptake systems. , for example, has three types of K uptake systems, which include the low-K-inducible KdpFABC system and two constitutive systems, Trk (TrkAG and TrkAH) and Kup. ORS571, a rhizobium that forms nitrogen-fixing nodules on the stems and roots of , also has three types of K uptake systems.

phrR-like gene praR of Azorhizobium caulinodans ORS571 is essential for symbiosis with Sesbania rostrata and is involved in expression of reb genes.

This study focuses on the function of the gene praR that encodes a putative transcription factor in Azorhizobium caulinodans ORS571, a microsymbiont of Sesbania rostrata. The praR gene is a homolog of the phrR gene of Sinorhizobium medicae WSM419, and the praR and phrR homologs are distributed throughout the class Alphaproteobacteria. The growth and nitrogen fixation activity of an A.

Comparative genome-wide transcriptional profiling of Azorhizobium caulinodans ORS571 grown under free-living and symbiotic conditions.

The whole-genome sequence of the endosymbiotic bacterium Azorhizobium caulinodans ORS571, which forms nitrogen-fixing nodules on the stems and roots of Sesbania rostrata, was recently determined. The sizes of the genome and symbiosis island are 5.4 Mb and 86.