Identification and functional characterization of ABCC transporters for Cd tolerance and accumulation in Sedum alfredii Hance

Abstract

AbstractCd is one of the potential toxic elements (PTEs) exerting great threats on the environment and living organisms and arising extensive attentions worldwide.Sedum alfrediiHance, a Cd hyperaccumulator, is of great importance in studying the mechanisms of Cd hyperaccumulation and has potentials for phytoremediation. ATP-binding cassette sub-family C (ABCC) belongs to the ABC transporter family, which is deemed to closely associate with multiple physiological processes including cellular homeostasis, metal detoxification, and transport of metabolites. In the present work, ten ABCC proteins were identified inS. alfrediiHance, exhibiting uniform domain structure and divergently clustering with those fromArabidopsis. Tissue-specific expression analysis indicated that someSaABCCgenes had significantly higher expression in roots (Sa23221andSa88F144), stems (Sa13F200andSa14F98) and leaves (Sa13F200). Co-expression network analysis using these fiveSaABCCgenes as hub genes produced two clades harboring different edge genes. Transcriptional expression profiles responsive to Cd illustrated a dramatic elevation ofSa14F190andSa18F186genes. Heterologous expression in a Cd-sensitive yeast cell line, we confirmed the functions ofSa14F190gene encoding ABCC in Cd accumulation. Our study performed a comprehensive analysis of ABCCs inS. alfrediiHance, firstly mapped their tissue-specific expression patterns responsive to Cd stress, and characterized the roles ofSa14F190genes in Cd accumulation.