摘要The heavy metal cadmium(Cd)is detrimental to crop growth and threatens human health through the food chain.To cope with Cd toxicity,plants employ multiple strategies to decrease Cd uptake and its root-to-shoot translocation.How-ever,genes that participate in the Cd-induced transcriptional regulatory network,including those encoding transcription factors,remain largely unidentified.In this study,we demon-strate that ENDO-BETA-MANNASE 7(MAN7)is necessary for the response of Arabidopsis thaliana to toxic Cd levels.We show that MAN7 is responsible for mannase activity and modulates mannose content in the cell wall,which plays a role in Cd compartmentalization in the cell wall under Cd toxicity conditions.Additionally,the repression of root growth by Cd was partially reversed via exogenous application of mannose,suggesting that MAN7-mediated cell wall Cd re-distribution depends on the mannose pathway.Notably,we identified a basic leucine zipper(bZIP)transcription factor,bZIP44,that acts upstream of MAN7 in response to Cd toxicity.Transient dual-luciferase assays indicated that bZIP44 directly binds to the MAN7 promoter re-gion and activates its transcription.Loss of bZIP44 function was associated with greater sensitivity to Cd treatment and higher accumu-lation of the heavy metal in roots and shoots.Moreover,MAN7 overexpression relieved the inhibition of root elongation seen in the bzip44 mutant under Cd toxicity conditions.This study thus reveals a pathway showing that MAN7-associated Cd tolerance in Arabidopsis is con-trolled by bZIP44 upon Cd exposure.