INSTITUTO DE BIOTECNOLOGIA Y BIOLOGIA MOLECULAR
Unidad Ejecutora - UE
congresos y reuniones científicas
Use of Recombination-Based In Vivo Expression Technology (RIVET) for the identification of Sinorhizobium meliloti genes induced by sub-lethal concentrations of hydrogen peroxide.
DAIANA ESCANCIANO; MARÍA EUGENIA SALAS; FLORENCIA ALVAREZ; JOSÉ LUIS LÓPEZ; WALTER DRAGHI; ANTONIO LAGARES; MAURICIO LOZANO
Congreso; XI Congreso Argentino de Microbiología General (SAMIGE); 2015
SAMIGE-Asociación Civil de Micobiología General
Sinorhizobium meliloti is a gram-negative proteobacterium able to establish nitrogen-fixingsymbiosis with legumes of the genera Medicago,Melilotus, and Trigonella. This symbiotic interaction is a highly regulatedprocess that involves a complex bidirectional molecular dialog which ends withthe differentiation of the rhizobium into a nitrogen fixing bacteroid and thegeneration of a new plant organ, the nodule. Several of the signal moleculesinvolved have been identified, and among them, a signal role for the hydrogenperoxide has been proposed. In this work we make use of a Recomination-based in vivo expression technology(RIVET) system modification created in our laboratory for the identification ofgenes induced during the growth of Sinorhizobiummeliloti in complex media supplemented with sub-lethal concentrations ofhydrogen peroxide. Using this approach we were able to identify that the cyaD1 gene, which shows a typical typeIII adenylate cyclase/guanylate cyclase (AC/GC) structural organization(namely, an amino-terminal signal peptide, a CHASE2 extracellular domain, a setof three membrane-spanning domains, and a cytoplasmic catalytic domain), isdifferentially induced by hydrogen peroxide. This fact might indicate apossible role of the second messenger cAMP in the signaling path of hydrogenperoxide during the symbiotic interaction. Preliminary results obtained with a cyaD1 mini-Tn5 insertional mutant indicatealso a possible role of this protein in hydrogen peroxide tolerance.