ARE CO-CULTURED RHIZOSPHERIC STRAINS UNDER ARSENIC STRESS MORE VIABLE?

OLMOS NICOTRA F; BRESER L; PORPORATTO C; AGOSTINI E; TALANO MA

La Falda

Jornada; XXI Jornadas Sociedad de Biología de Córdoba.10-12 de Agosto 2017, La Falda.; 2017

Sociedad de Biología de Córdoba

Co-inoculation of plants with rhizobacteria allows to complement different growth promoting properties, offering interesting results evenunder adverse environmental conditions such as high metals/metalloids concentration. The aim of this study was to evaluate the viabilityof two rhizospheric strains (Bradyrhizobium japonicum E109 and Azospirillum brasilense Az39) under AsV and AsIII exposure, and theeffect of a phytohormone produced by Az39, indole-3-acetic acid (IAA), on E109 survival. Flow cytometry analysis revealed thatAsexposure led to a reduction ofE109cell size (FSC) but not Az39. Cell granularity (SSC) of both strainswas not modified. Regarding tometalloid toxicity, both strains showed significant increase of mortality under AsIII treatment, whereas AsV did not produce a significanteffect compared to bacteria grown under control conditions. It is noteworthy that when the bacteria were co-cultured their survival wasimproved, either under control or As conditions. However, IAA was not responsible for the major survival of E109. Thus, compoundsexudated by Az39 should be studied to find the compound producing the protective effect on E109, the strain more sensitive to metalloid.Nevertheless, these findings indicate that there is a positive interaction between both strains when they are co-cultured in controlcondition or As stress. Therefore, co-inoculation would give several advantages to As-stressed plants.