An effective peanut-Bradyrhizobium sp. symbiotic interaction restraints arsenic translocation and accumulation in plants.

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

Congreso; III IBEMPA- XXVIII RELAR- XVI SEFIN.; 2017

Arsenic (As) constitutes a global environmental problem. In Argentine, Córdoba province´s groundwater presents high As concentration, reaching in some cropping areas 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 differential response of the symbiotic interaction established with bacterial strains and peanut plants exposed to a realistic dose of As supply (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. As addition on plants inoculated with Bradyrhizobium sp. SEMIA6144 caused a decrease in shoot length and 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 promoting As phytostabilization. Peanut inoculation, with both tested strains, allowed the legume development in terms of minimal effects on plant growth when exposed to a realistic As concentration. Nevertheless, Bradyrhizobium sp. SEMIA6144 results to be better inoculant that could restraint metalloid translocation and accumulation to edible parts of the legume, avoiding fruit contamination and human poisoning.