Bio-organic Fertilizer Facilitated Phytoremediation of Heavy Metal(loid)s Contaminated Saline Soil by Mediating The Plant-Soil-Rhizomicrobiota Interactions

Bio-organic fertilizer (BOF) was effective to promote the phytoremediation efficiency of heavy metal(loid)s contaminated saline soil (HCSS) by improving rhizosphere soil properties, especially microbiome. However, there existed unclear impacts of BOF on plant metabolome and plant-driven manipulation on rhizosphere soil microbiota in HCSS, which were pivotal contributors to stress defense of plants trapped in adverse conditions. Here, a pot experiment was conducted to explore the mechanisms of BOF in improving alfalfa (Medicago sativa)-performing phytoremediation of HCSS. In addition to enhancements of rhizosphere soil physicochemical properties and microbiome, the conjoint analysis of plant metabolome and physiological indices confirmed that BOF reprogrammed the metabolic processes and biochemical pathways that are associated intimately, thus boosting the phytoremediation efficiency and adaptation of alfalfa. The consortium of root metabolome, soil metabolome, and soil microbiome revealed that BOF highlighted the plant-driven regulation on rhizosphere soil microbes and environment. By compiling various results and omics data, it was concluded that BOF favored the phytoremediation by mediating the plant-soil-rhizomicrobiota interactions. The results would deepen understanding of the mechanisms by which BOF improved phytoremediation of HCSS, and provide theoretical guidance to soil amelioration and BOF application.