Drought stress effects on carbon and nitrogen metabolism in the peanut-rhizobia interaction

PERALTA, JUAN MANUEL; FURLAN, ANA LAURA; SEQUEIRA, MICAELA; BIANUCCI, ELIANA; DIETZ, KARL-JOSEF; CASTRO, STELLA

Córdoba

Congreso; LII Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2016

Universidad Nacional de Córdoba

The peanut-rhizobia interaction is valuable for the development of sustainable agriculture practices; however, such interaction can be affected by intermittent episodes of drought stress. In this work, the impact of drought stress and rehydration on peanut plants and the role of carbon (C) and nitrogen (N) metabolism in the response of drought-tolerant cultivars were analyzed. The water status, growth and biological nitrogen fixation (BNF); the gene expression by qPCR and the specific activity of C and N metabolism-enzymes; and the metabolite profile by GC-MS were determined in drought-tolerant and drought-sensitive cultivars. The results revealed that nodulation and BNF were decreased in the sensitive cultivar and unchanged in the tolerant cultivar, despite a similar water status. Then, it was suggested that the tolerant cultivar had the ability to trigger a metabolic response which underlies the tolerance to drought. In the tolerant cultivar, the content of compounds with a protective role against stress, such as gamma-aminobutyric acid, proline and trehalose were increased. Besides, the sucrose accumulation was associated with a decreased expression and activity of sucrose synthase although the N assimilation was unchanged. Thus, the tolerant cultivar sustained the respiratory substrates for the highly-demanding BNF, a mechanism that contributed to the tolerance exhibited.