Crosstalk between glomalin and AMF reduces cadmium uptake and leaching, enhancing pea yield and soil health.

Abstract

Untreated effluents from the pottery industry pose ecological and human health risks by polluting soil, food crops, and groundwater with cadmium (Cd). Arbuscular mycorrhizal fungi (AMF) and easily extractable glomalin (EG) secreted by AMF can immobilize Cd in soil and minimize its migration to food crops and groundwater. This study hypothesized that applying EG and AMF together in Cd-polluted soil may result in their synergistic crosstalk. This synergism can reduce Cd migration from soil to plants and groundwater, and improve plant traits and soil health compared to the sole application of AMF and EG. This pot study investigated a novel idea: amending pottery Cd-polluted soil with sole AMF inoculum, EG, and AMF + EG. Later, Cd bioavailability in soil and its migration in pea plants and leachates, as well as plant growth and yield, grain nutrition, and activities of soil enzymes, were examined. A synergistic interaction between AMF and EG occurred in the AMF + EG treatment, which reduced the concentrations of bioavailable Cd in soil, plant shoots, roots, and grain by 64%, 68%, 53%, and 89%, respectively, while improving grain nutrients than untreated control treatment (CK). Surprisingly, Cd concentrations in grain and leachates were below the permissible limits of FAO and WHO for food and drinking water safety with AMF + EG. Moreover, maximum improvements in dry weight of pea shoot (36%) and root (60%), pod numbers (144%), and grain yield (58%) were noted with AMF + EG than CK. The highest rise in soil enzymatic activities, i.e., β-glucosidase (68%), urease (72%), catalase (206%), chitinase (87%), and phosphomonoesterase (172%) with AMF + EG compared to CK, indicated maximum improvements in soil health. Synergism between AMF and EG in AMF + EG treatment can efficiently remediate Cd-polluted soils, reduce Cd migration to food and groundwater, and improve soil and plant health.