METABOLOMIC ANALISYS OF ACID-ADAPTED (ATR+) Sinorhizobium meliloti

ALBICORO, F.J.; LAGARES A.; DRAGHI, W.O.; PUHLER, A.; DEL PAPA, M.F.; DRAGHI, W.O.; PISTORIO, M.; LAGARES, A.; NIEHAUS, K.

Pucón

Taller; III Taller Latinoamericano de PGPR; 2016

Sinorhizobium meliloti establishes anitrogen-fixing symbiosis with Medicago species. In the soil environmentboth partners need to surpass biotic and abiotic stress factors to achieve asuccessful symbiotic system. It is widely recognizable that the Medicago-Sinorhizobiumsymbiosis is highly sensitive to acid stress. To cope with low pH, S.meliloti is able to induce an acid tolerance response (ATR+ response),which not only support a better survival under acidity, but also results in amore competitive symbiotic. To characterize the biochemistry of ATR+ rhizobia,a metabolomic approach was used. The results showed changes in the centralcarbon metabolic pathways making them more active for NAD(P)H supply, likely asa consequence of higher demands for this nucleotide under acid stress.Significant changes in 27 out of 61 detected metabolites were observed,including Gluconate-6-P, Glycerate-3-P, Gluconate, Pep, Serine, Homoserine,Fructose, Glycerate, O-succinyl-Homoserine, Fructose-6-P,Glycerate-2-P,2-Isopropylmalate, Urea, Pyruvate, Homocysteine, Glucose-6-P, Lactic Acid,Alanine, Sucrose, Gluconolactone, Shikimate, a-Glycerophosphate, Methylcitrate,Proline, Uracil, myo-Inositol and Ribose-5-P. In addition enzymatic activitiesinvolved in synthesis/degradation of some of the altered metabolites showedcongruent responses with the observed changes their substrates/products cytoplasmicconcentration. The observed metabolic changes are part of the induced cellularactivities to help maintaining the intracellular pH homeostasis in thecytoplasm. New proteomic and transcriptomic data of the ATR+ vs. ATR- rhizobiawill be necessary to help understanding how the more acid-tolerant rhizobiaalso express a more competitive symbiotic phenotype.