PvERF104 confers cadmium tolerance in Arabidopsis: Evidence for metal-responsive element-binding transcription factors

Abstract

Cadmium (Cd) is highly toxic to all organisms including plants, and transcription factors are essential regulators for Cd-responsive genes. In animals, metal-responsive transcription factor-1 (MTF-1) is a unique and main transcriptional activator for heavy metal detoxification through binding metal-responsive elements (MREs). However, plants have no homologs of MTF-1, and whether there are MRE-binding transcription factors in plants remain largely unknown. Previously, we identified an MRE-binding transcription factor 1 (PvMTF-1) from the bean (Phaseolus vulgaris). Unfortunately, PvMTF-1 is an orphan protein and cannot represent a conserved MRE-binding transcription factor family in plants. Here, we isolated and characterized bean ethylene response transcription factor (ERF) 104 (PvERF104) as a functional MRE-binding transcription factor. PvERF104 was isolated from the bean by yeast one-hybrid screens using the MRE as a bait. PvERF104 acted as an MRE-dependent transcriptional repressor. Expression of PvERF104 relieved Cd-induced lipid peroxidation and reduced Cd accumulation, and then moderately improved Cd tolerance in Arabidopsis. Further analyses showed that PvERF104 directly or indirectly regulated the expression of MRE-containing Cd stress-related genes, and subsequently influenced Cd tolerance. Thus, PvERF104 represents a member of ERF-type MRE-binding transcription factors. Our findings thereby provide new insights into the roles and mechanisms of MRE-binding transcription factors in plants against Cd. Data AvailabilityData will be made available on request.