Boosting multi-heavy metal sequestration in king grass:Unveiling the role of Serendipita indica symbiosis and the key root exudate GABA
简介：This study investigated the symbiosis between Serendipita indica and king grass to optimize cadmium(Cd)and chromium(Cr)phytoextraction from contaminated soils,focusing on root exudate dynamics and γ-aminobutyric acid(GABA)signaling in rhizoremediation.We examined mechanisms linking heavy metals(HMs),microbial symbiosis,and root exudates in the rhizosphere during remediation.S.indica promoted plant growth,increasing biomass by 10.2％-17.7％,and enhanced root vigor and development.It also boosted antioxidant enzymes(SOD,APX,GR)by 11.5％,27.7％,and 15.0％,respectively,while reducing MDA and H2O2,thereby alleviating HM stress.Root uptake of Cd and Cr increased by 23.2％-30.0％and 20.8％-30.0％,while soil Cd and Cr removal increased by 27.5％and 28.7％.Under Cd/Cr stress,S.indica increased root vigor and regulated exudates by king grass,upregulating indole-3-acetic acid(IAA),betaine,ascorbic acid,riboflavin,and notably GABA,which in-creased 4.0-14.0 fold,reaching 19.2 mmol/mL at the tillering stage.These exudates correlated with Cr levels and growth promotion.S.indica upregulated the Alanine-Aspartate-Glutamate and Arginine-Proline pathways,closely associated with thetricarboxylic acid(TCA)cycle.Exogenous GABA further enhanced antioxidant responses,in-creased biomass by 34.1％-41.6％,and boosted Cr uptake and sequestration by 21.1％-25.1％,while inhibiting Cr translocation to aerial parts.This study highlights S.indica's growth-promoting effects,the role of GABA in root sequestration of HMs,and their potential in phytoremediation,thereby offering new opportunities for improving phytoremediation technologies.展开
