Synthetic bacterial community derived from Astragalus mongholicus and plant-plant interactions inhibit cadmium uptake by modulating gene expression, antioxidant system and carbohydrate metabolism under cadmium contaminated soil

In this study we evaluated an alternative strategy to inhibit cadmium (Cd) uptake with synthetic bacterial community (SynCom) in cereal-legume intercropping under Cd contaminated soil. The results exhibited that intercropping coupled with SynCom inoculation promoted wheat biomass and inhibits Cd uptake in shoot (-65.05%), root (-34.66%) and grain (-74.45%) over monoculture without inoculation under Cd stress. However, antioxidant enzyme activities were significantly increased with SynCom inoculation in wheat grown on Cd contaminated soil irrespective of intercropping. SynCom inoculation considerably increased cytoplasmic invertase, vacuolar invertase, hexokinase, phosphoglucoisomerase, glucose-6-phosphate dehydrogenase, phosphofructokinase and SuSy while decreased the activities of ADP-Glucose pyrophosphorylase, aldolase, fructokinase, phosphoglucomutase and UDP-glucose pyrophorylase irrespective of intercropping under Cd stress. Furthermore, the expressions of gene encoding heavy metal stress were significantly decreased with the SynCom inoculation in roots. The expression of TaHMA3-b in root was downregulated by SynCom inoculation in wheat grown under Cd stress. The expressions of gene encoding heavy metal stress in shoot were downregulated by SynCom inoculation over other treatments. These findings not only offered useful information for future study of interaction mechanisms between intercropping and SynCom inoculation, but also demonstrated a suitable technological approach for remediation coupled with agro-production in mildly to substantially Cd polluted soil.