PROTEOMIC ANALYSIS OF Rhizobium sp. LPU83 UNDER ACID STRESS USING AN ORBITRAP MASS SPECTROMETER

JULIET NILSON; FRANCISCO ALBICORO; GONZALO A. TORRES TEJERIZO; WALTER O. DRAGHI; JULIETA FERNANDEZ; MARIANO PISTORIO

Mar del Plata

Congreso; LI Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2015

Oregon-like rhizobia areacid-tolerant bact eria, very competitive for the nodulati on of alfalfa inacid soils although inefficient for biological nitrogen fixation. Thesefeatures place these rhizobia as a potential risk factor in agricultural soilswhen compete with efficient symbiont Ensifer meliloti . In this work we studiedthe global proteome responses of Rhizobium sp. LPU83 under acid stress. Initia lly,by evaluation of growth kine tics over pHs ranging from 4 to 7, the acidiccondition was chosen. Proteome was analyzed by nano-flow ultra-high-performanceliquid chromatography coupled to a quadrupole Orbitrap mass spectrometer foriden tifying proteins possibly involved in acid tolerance. A total of 864proteins were identified. Fifty-one of them were significantly up-regulated andeighteen were down- regulated. In silico characterization of thes e proteinsrevealed differences between stressed and non-stressed cells. A group ofup-regulated proteins might be involved in alanin e, aspartate and glutamate metabolism, and another group in oxidative phosphorylation, stimulating energyproduction. These proteomics-based results could help to improve ourunderstanding in the acid tolerance in rhizobia.