Vol.:(0123456789) 1 3 World Journal of Microbiology and Biotechnology (2020) 36:23 https://doi.org/10.1007/s11274-020-2800-0 ORIGINAL PAPER Arsenic accumulation by a rhizosphere bacterial strain Ochrobactrum tritici reduces rice plant arsenic levels Merijn Moens 1  · Rita Branco 1  · Paula V. Morais 1,2 Received: 30 July 2019 / Accepted: 8 January 2020 © Springer Nature B.V. 2020 Abstract Arsenic naturally occurs in the earth’s crust and can be introduced in the environment by human activities. Agricultural practices in arsenic-contaminated environments pose a threat to human health. The contamination of crops contributes to the metalloid’s introduction in the food chain. This study aims to test the hypotheses that the inoculation of a hyperaccumulator rhizobacterial strain, Ochrobactrum tritici As5, to the rhizosphere of rice plants reduces the arsenic presence inside the tis- sue of the rice plants and reduces the inhibitory efect of the metalloid on the plant’s growth parameters. Inoculation of the hyperaccumulating strain O. tritici As5 showed the lowest concentration of arsenic in the plant’s tissue (2.6 fold lower than sterile plants), compared to the unmodifed type O. tritici SCII24 and sterile rice plants. The inoculation of the type strain SCII24 also led to a decrease in arsenic concentration in the plant tissue compared with sterile plants (1.6 fold lower than sterile plants). The diference in arsenic presence in shoots was smaller among treatment groups than in the roots, showing a similar trend. The inoculation of the hyperaccumulator As5 strain alleviated some of the toxic efects of arsenic on shoot growth compared to inoculation of the unmodifed type strain. All these fndings together, contribute to our understanding of the interplay between arsenic pollution, plants and their rhizobacteria, especially the role of bioaccumulation of metal(oids) by rhizobacteria, and provide important information on the prevention of arsenic uptake by crops and the development of phytostabilizers. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s11274-020-2800-0) contains supplementary material, which is available to authorized users. * Paula V. Morais pvmorais@ci.uc.pt 1 CEMMPRE – Centre for Mechanical Engineering, Materials and Processes, University of Coimbra, 3030-788 Coimbra, Portugal 2 Department of Life Sciences, FCTUC, University of Coimbra, 3004-517 Coimbra, Portugal