Journal of Applied Microbiology, Vol.122, No.4, 987-996, 2017
An indoleacetic acid-producing Ochrobactrum sp MGJ11 counteracts cadmium effect on soybean by promoting plant growth
AimsTo analyse whether some indoleacetic acid (IAA)-secreting plant growth-promoting bacteria can alleviate cadmium (Cd) stress, the role of an Ochrobactrum sp. MGJ11 from rhizosphere of soybean in promoting plant growth, and to evaluate the counteracting Cd effects on soybean. Methods and ResultsOchrobactrum sp. MGJ11 produced 1212mgl(-1) of IAA. MGJ11 increased soybean root length, shoot length and biomass by 301, 308 and 134% respectively. In liquid medium, no IAA production was detected in Cd concentration of 100mgl(-1). In soil with 20-80mgkg(-1) Cd, MGJ11 promoted soybean root elongation (294-1614%) and increased the shoot length (up to 527%) and biomass (up to 872%). After growing for 38days, Cd concentrations in the roots of inoculated soybean were lower than in those of noninoculated plants. Only a little Cd (26-169gg(-1)) was translocated from the root to shoot. ConclusionsOchrobactrum sp. MGJ11 secretes IAA and shows tolerance against Cd. MGJ11 inoculation improves the root length, shoot length and biomass of soybean in both vermiculite and Cd vermiculite, and decreases Cd concentration of soybean root. The characteristics of MGJ11 suggest that it could be used for promoting soybean growth and lowering bioavailability of soil Cd for soybean root. Significance and Impact of the StudyIn this study, we isolated a plant growth-promoting Ochrobactrum with the activity of mitigating Cd toxicity to plant roots. The Ochrobactrum can be considered as a potential bioaugmentation agent that promotes plant growth, especially in some agricultural systems, or that helps in the phytoremediation of Cd-contaminated soil.