Improving soybean growth under arsenic stress by inoculation with native arsenic-resistant bacteria

WEVAR OLLER, ANA LAURA; REGIS, SOFÍA; ARMENDARIZ, ANA LAURA; TALANO, MELINA ANDREA; AGOSTINI, ELIZABETH

PLANT PHYSIOLOGY AND BIOCHEMISTRY

ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER

Año: 2020

0981-9428

Certain metal(loid)-resistant bacteria that inhabit therhizosphere have shown to improve plant growth and tolerance under toxicmetal stress. In this study, we tested if six native, arsenic-resistantand plant growth promoting rhizobacteria (PGPR) were able to enhancesoybean (Glycine max L.) growth and modulate arsenic (As) uptake. As aprevious work, we tested all single isolates and all possible binarycombinations without arsenic stress to identify the combinations thatwould have the greatest plant growth promoting effect. In this study, ascreening assay was performed with only five inoculation options selectedafter first stage (Pseudomonas sp. AW4, Pseudomonas sp. AW6, AW4+AW6,Rhodococcus sp. AW3+Pseudomonas sp. AW5 and Enterobacter sp. AW1+AW6). Inboth stages, inoculation was implemented by imbibition of soybean seedswith bacterial suspensions, and plant growth was carried out in potsusing perlite as substrate in a chamber with controlled conditions. Inthe third stage, we performed similar assays, under As stress, using thethree most promising inoculation options (AW4, AW6 and AW3+AW5).Treatments were performed by irrigation with 25 μM arsenite (As3+), 25 μMarsenate (As5+), 25 μM equimolar As3+/As5+ solution or water (control).Biometric and biochemical parameters indicated that inoculation withPseudomonas sp. AW4 significantly promoted soybean growth under As3+/As5+treatment and did not modified As accumulation pattern. Further fieldstudies are needed to determine if some of these inoculation options areuseful to improve in situ soybean growth under arsenic stress and couldbecome a tool for the development of sustainable agriculture in Asimpactedenvironments.