Identification and functional analysis of cation-efflux transporter 1 from Brassica juncea L

Lu Han, Xiaohua Wu, Xinyu Zhang, Kailin Hou, Hongshan Zhang, Chenjia Shen
2022 BMC Plant Biology  
Background Brassica juncea behaves as a moderate-level accumulator of various heavy metal ions and is frequently used for remediation. To investigate the roles of metal ion transporters in B. juncea, a cation-efflux family gene, BjCET1, was cloned and functionally characterized. Results BjCET1 contains 382 amino acid residues, including a signature motif of the cation diffusion facilitator protein family, six classic trans-membrane-spanning structures and a cation-efflux domain. A phylogenetic
more » ... nalysis showed that BjCET1 has a high similarity level with metal tolerance proteins from other Brassica plants, indicating that this protein family is highly conserved in Brassica. BjCET1 expression significantly increased at very early stages during both cadmium and zinc treatments. Green fluorescence detection in transgenic tobacco leaves revealed that BjCET1 is a plasma membrane-localized protein. The heterologous expression of BjCET1 in a yeast mutant increased the heavy-metal tolerance and decreased the cadmium or zinc accumulations in yeast cells, suggesting that BjCET1 is a metal ion transporter. The constitutive expression of BjCET1 rescued the heavy-metal tolerance capability of transgenic tobacco plants. Conclusions The data suggest that BjCET1 is a membrane-localized efflux transporter that plays essential roles in heavy metal ion homeostasis and hyper-accumulation.
doi:10.1186/s12870-022-03569-x pmid:35387616 pmcid:PMC8985314 fatcat:pks2gue7gbgcfi6rumz3qt3jja