Proteomic analysis of Rhizobium sp. LPU83 under acid stress using an Orbitrap mass spectrometer

NILSSON, J; ALBICORO, F.; TORRES TEJERIZO, G. A.; DRAGHI, W. O.; FERNANDEZ, J.; PISTORIO, M.

Mar del Plata

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

SAIB

Oregon-like rhizobia are acid-tolerant bacteria, very competitive for the nodulation of alfalfa in acid soils although inefficient for biological nitrogen fixation. These features place these rhizobia as a potential risk factor in agricultural soils when compete with efficient symbiont Ensifer meliloti. In this work we studied the global proteome responses of Rhizobium sp. LPU83 under acid stress. Initially, by evaluation of growth kinetics over pHs ranging from 4 to 7, the acidic condition was chosen. Proteome was analyzed by nano-flow ultra-high-performance liquid chromatography coupled to a quadrupole Orbitrap mass spectrometer for identifying proteins possibly involved in acid tolerance. A total of 864 proteins were identified. Fifty-one of them were significantly up-regulated and eighteen were down-regulated. In silico characterization of these proteins revealed differences between stressed and non-stressed cells. A group of up-regulated proteins might be involved in alanine, aspartate and glutamate metabolism, and another group in oxidative phosphorylation, stimulating energy production. These proteomics-based results could help to improve our understanding in the acid tolerance in rhizobia.