INVESTIGADORES
LAGARES Antonio
congresos y reuniones científicas
Título:
Metabolome analysis of acid grown Sinorhizobium meliloti (Sme)
Autor/es:
DRAGHI, W. O.; LOZANO M. J.; GIUSTI M. A.; PISTORIO M.; LAGARES A.
Lugar:
Rosario, Sante Fe, Argentina
Reunión:
Congreso; XLII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2006
Institución organizadora:
Sociedad Argentina de Investigación en Bioquímica y Biología Molecular
Resumen:
Sme is an alfa-proteobacteria able to fix nitrogen-in symbiosis
with Medicago spp. As soil microorganisms, rhizobia must
overcome different stress conditions in free-living before entering
the plant root. Soil acidity is a challenging environmental stress
frequently present in agricultural fields, and Sme is particularly
sensitive to the acid media. We approached a metabolome
analysis of acid-stressed rhizobia to get a deeper insight into the
physiology of the acid growth. Bacterial cells were grown in batch
cultures using defined minimal medium (early log phase of
growth), both at neutral and moderately acid (pH 6.1) pH. It is
already known that during acid cultivation Sme triggers an Acid
Tolerance Response. Seventy metabolites from cells in ATR
phase were analyzed by GC/MS and compared with the same
compounds from the neutral cultures. Significant differences in
several amino acid were observed (p=0.05). Analysis of the
central carbon metabolism showed that under acid cultivation
rhizobia accumulate metabolites that belong to the pentose
phosphate pathway (PPP); together with an increase of
metabolites that connect PPP with the TCA cycle. The increase
in the biosynthetic PPP intermediates correlates with a
concomitant increase in exopolysaccharide production, and most
likely with a decrease in the aerobic metabolism as shown by
lower amounts of the first two TCA intermediates.