Aislamiento y caracterización de rizobios de A. correntina silvestre capaces de nodular A. hypogaea cv. Granoleico

GONZALEZ P; LASCANO HR.; MELCHIORRE M

Rosario

Congreso; XXXIII Reunión Argentina de Fisiología Vegetal; 2021

Soc Argentina de Fisiologia Vegetal

Drought and salinity conditions are the major factors affecting nitrogen fixation by legume-rhizobium symbiosis. The increase of intracellular reactive oxygen species (ROS), as a consequence, leads to activation of antioxidant system both in plant and bacteria as physiological response to prevent the toxic effects of oxidative stress. The mlr7636 superoxide dismutase gene was constitutively overexpressed in Sinorhizobium meliloti and Mesorhizobium japonicum MAFF303099 to test if the enhanced sod activity in bacteria contributes to mitigate the effects of salt stress on legumes. Salt stress treatments were 200 mM for Medicago sativa PROINTA Súper Monarca and NaCl 150 mM for Lotus japonicus MG20 in seed germinating pouches. Salt stress affected nodulation in both, M. sativa and L. japonicus when inoculated with non sod overexpressing strains. However, in stress, the inoculation of S. meliloti sod+ to M. sativa has restored the effects of salinity on nodulation, whereas inoculation of M. japonicum sod+ has inhibited nodulation on L. japonicus. In spite of inhibition of nodulation, the M. japonicum sod+ inoculation has mitigated the effects of salinity on L. japonicus promoting growth of aerial biomass and roots when compared to non-inoculated treatment. The effects seen in M. japonicum sod+ on L. japonicus in salinity might be due to plant growth promoting mechanisms.