AN EFFECTIVE PEANUT-BRADYRHIZOBIUM SP. SYMBIOTIC INTERACTION RESTRAINTS ARSENIC TRANSLOCATION IN PLANTS.

BIANUCCI ELIANA; PERALTA, JUAN MANUEL; FURLAN ANA; TRAVAGLIA CLAUDIA; CASTRO STELLA

Lima

Congreso; III CONFERENCIA IBEROAMERICANA DE INTERACCIONES BENEFICIOSAS PLANTA ? MICROORGANISMO ? MEDIO AMBIENTE (IBEMPA); 2017

Universidad Nacional Agraria La Molina

Arsenic (As) is a well-known toxic element that is of special interest in Córdoba province (Argentina) since around 90% of its groundwater has As concentrations coming from sedimentary depositions that exceed the maximum level allowed for drinking water (0.1 µM). In some regions, including cropping areas, As concentration in groundwater can reach up to 24 µM, which can be absorbed by plants or be used for artificial irrigation. The aim of this research was to elucidate the response of the symbiotic interaction established with bacterial strains and peanut plants exposed to a realistic dose of As (3 µM). The reference strains, Bradyrhizobium sp. SEMIA6144 and Bradyrhizobium sp. C-145, were able to grow at almost 1000-fold higher As concentration than the plant. Arsenic addition on plants inoculated with Bradyrhizobium sp. SEMIA6144 caused a decrease in shoot length and dry weight. Regardless of the inoculated strain, a significant root length reduction was also observed at the mentioned condition. Peanut plants inoculated with Bradyrhizobium sp. C-145 showed higher nodule number than Bradyrhizobium sp. SEMIA6144, without differences in nodule dry weight. All these variables were significantly reduced by As addition accompanied by oxidative damage. Metalloid distribution pattern was similar between tested strains, remarkably, peanut inoculation with Bradyrhizobium sp. SEMIA6144 revealed a significant lower translocation factor than Bradyrhizobium sp. C-145 enhancing As phytostabilization. Peanut inoculation, with both tested strains, allowed the legume development in terms of minimal effects on plant growth exposed to As. Nevertheless, Bradyrhizobium sp. SEMIA6144 is the best inoculant, between tested strains, for limiting metalloid translocation and accumulation to edible parts of the legume, avoiding fruit contamination and human poisoning. Research supported by SECYT-UNRC, CONICET and ANPCyT.