Impact of arsenic in Bradyrhizobia strains and in the symbiotic interaction with peanut plant

BIANUCCI, ELIANA; FURLAN, ANA LAURA; ISAIA, ARACELI; PERALTA, JUAN MANUEL; HERNÁNDEZ, LUIS E.; CASTRO, STELLA

Córdoba

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

Universidad Nacional de Córdoba

Arsenic (As) contamination constitutes a serious problem in the environment. The aim of this work was to evaluate As effects on the production of reactive oxygen species, the occurrence of oxidative damage and the activity of the antioxidant system in peanut microsymbionts and in the establishment of peanut-bradyrhizobia symbiotic interaction.Bradyrhizobiumsp. viability test allowed to classifyB. sp. SEMIA6144 as sensitive to As, whereasB. sp. C-145,B. sp. NOD31 andB. sp. NLH25 as tolerant. Then, the oxidative and antioxidant defense response were analyzed in an As-sensitive and As-tolerant strain (B. sp. SEMIA6144 andB. sp. C-145, respectively). The sensitive strain showed oxidative stress symptoms as evidenced by the increased lipid peroxidation, induced by H2O2content increment. Moreover, SOD and GPX activity increased by As treatment however, CAT, GR and GST activities were reduced. In the tolerant strain H2O2content was enhanced but not enough to induce oxidative stress. GST, CAT and GPX activities were unchanged whereas SOD and GR activities were reduced in presence of As. Inoculated peanut plants exposed to As showed a decreased ROS accumulation and increased GSH content and GST activity in roots. Thus, GSH and related enzymes play an important role in As detoxification of free living rhizobia and in the first step of the symbiotic interaction established with peanut