biostudies-literatureUnknown76(24)Kohler PRThe nitrogen-fixing symbiont of alfalfa, Sinorhizobium meliloti, is able to use myo-inositol as the sole carbon source. Putative inositol catabolism genes (iolA and iolRCDEB) have been identified in the S. meliloti genome based on their similarities with the Bacillus subtilis iol genes. In this study, functional mutational analysis revealed that the iolA and iolCDEB genes are required for growth not only with the myo-isomer but also for growth with scyllo- and d-chiro-inositol as the sole carbon source. An additional, hypothetical dehydrogenase of the IdhA/MocA/GFO family encoded by the smc01163 gene was found to be essential for growth with scyllo-inositol, whereas the idhA-encoded myo-inositol dehydrogenase was responsible for the oxidation of d-chiro-inositol. The putative regulatory ioApplied and environmental microbiology7972-80https://www.ebi.ac.uk/biostudies/studies/S-EPMC3008233biostudies-literatureInositol catabolism, a key pathway in sinorhizobium meliloti for competitive host nodulation.PMC3008233Rossbach SZheng JYKohler PRSchoffers EfalseInositol catabolism, a key pathway in sinorhizobium meliloti for competitive host nodulation.The nitrogen-fixing symbiont of alfalfa, Sinorhizobium meliloti, is able to use myo-inositol as the sole carbon source. Putative inositol catabolism genes (iolA and iolRCDEB) have been identified in the S. meliloti genome based on their similarities with the Bacillus subtilis iol genes. In this study, functional mutational analysis revealed that the iolA and iolCDEB genes are required for growth not only with the myo-isomer but also for growth with scyllo- and d-chiro-inositol as the sole carbon source. An additional, hypothetical dehydrogenase of the IdhA/MocA/GFO family encoded by the smc01163 gene was found to be essential for growth with scyllo-inositol, whereas the idhA-encoded myo-inositol dehydrogenase was responsible for the oxidation of d-chiro-inositol. The putative regulatory io2010-01-01T00:00:00Z2010 Dec2025-04-03T22:22:27.992Z2019-03-27T00:37:35ZS-EPMC30082332097186210.1128/AEM.01972-1010.1128/aem.01972-10