RESPUESTAS FISIOLÓGICAS Y BIOQUÍMICAS DE LA CEPA Bradyrhizobium sp. TAL 169 RECOMENDADA COMO INOCULANTE DEL MANÍ BAJO ESTRÉS HÍDRICO INDUCIDO POR SOLUTOS NO IÓNICOS

BUSTO, VÍCTOR DANIEL, BUENO, MIGUEL A., GONZÁLEZ, PAOLA S., DARDANELLI, MARTA S., GARCÍA, MIRTA B. Y GHITTONI, NORA

México

Congreso; Congreso Internacional Virtual Agropecuario (CIVA)-México; 2002

Rhizobium-legume symbiosis produces crops improvements, peanut among them. Environmental stress can damage soil microorganisms by modifying some physiological and biochemical parameters. Our aim was to analyze the effects of water stress on the biochemical and physiological parameters of peanut Bradyrhizobium sp. strain TAL 169. This was grown at 28ºC on YEM, and/or supplemented with glycerol 350 mM or PEG-6000 16% W/V. Viability, biomass, proteins, oligosaccharides profile (as used by Ghittoni and Bueno, 1995), and cellular trehalose (Larsen, 1987), were measured. Lipids were obtained, phospholipids and neutral lipids were identified by TLC. Glycerol was unable to modify physiological and biochemical parameters, however was able to modify methyl esters and sterol esters concentration. The other non-ionic solute (PEG) modified physiological parameters: bacterial growth and viability decreased 36%, biomass increased nine fold and generation time 113%. On the other hand, biochemical parameters were modified, but not oligosaccharides profile. Protein content and phosphatidylcholine concentration were increased. Phosphatidylethanolamine and cardiolipin appeared with PEG while methyl esters, triglycerides and sterol esters disappeared. Trehalose was detected in the control and raised 93% in the presence of PEG. Since trehalose would behave as a cellular protect in water stress strain TAL 169 could adapt in spite of difficulty to grow. Oligosaccharides biosynthesis wasn’t inhibited by PEG, perhaps due to it would be influenced by ionic strength instead hiperosmolarity. Some phospholipids and neutral lipids became main lipids as occur with other stresses. These changes would be involved in a structural and biochemical adaptation in response to water stress.