The effect of plant growth-promoting rhizobacteria (PGPR) on arsenic accumulation and the growth of rice plants (Oryza sativa L.)

Large areas of paddy fields in southern China have been contaminated by arsenic (As), which causes serious problems such as the reduction of grain yield and high As concentrations in brown rice. To test the possibility of using plant growth-promoting rhizobacteria (PGPR) to promote rice growth and decrease As accumulation in brown rice in such paddy fields, three As-resistant PGPRs (strains S6, S7 and S10) were isolated and incorporated into two rice cultivars (Zhendao 14 and Jianyou G2) grown in different environments. The results showed that all PGPRs promoted rice growth (grain yield increased by 10.50–51.30% under greenhouse conditions and by 4.83–9.16% in paddy fields) and reduced As damage in rice. Specifically, S10 decreased As accumulation in brown rice in both greenhouse (3.50–26.01%) and paddy-field conditions (9.26–10.50%) by significantly reducing the available As concentration in rhizospheric soil, especially in the Dabaoshan-B field (34.00%). Conversely, in greenhouse condition, strains S6 and S7 increased As concentrations by 6.10–20.10% and 2.14–14.60%, respectively. Our results suggested that PGPR inoculation could be used to decrease As accumulation and promote rice growth in As-contaminated paddy fields. However, as the effects of PGPRs differed by strain and depended on environmental factors, careful selection of the strains and environmental conditions, and pre-testing, will be essential before applying PGPRs to As-contaminated paddy fields. •The three isolated As-resistance PGPRs could promote rice growth and reduce As damage in rice.•S10 significantly decreased As(III) and total As content in brown rice grown in non-sterile greenhouse and paddy field.•The effects of PGPRs were influenced by both strains and environmental factors.•PGPR inoculation could be a potential method in decreasing As content and promoting rice growth in As-polluted paddy field.