title: Metallothionein 2 (SaMT2) from Sedum alfredii Hance confers increased Cd tolerance and accumulation in yeast and tobacco.
abstract: Metallothioneins are cysteine-rich metal-binding proteins. In the present study, SaMT2, a type 2 metallothionein gene, was isolated from Cd/Zn co-hyperaccumulator Sedum alfredii Hance. SaMT2 encodes a putative peptide of 79 amino acid residues including two cysteine-rich domains. The transcript level of SaMT2 was higher in shoots than in roots of S. alfredii, and was significantly induced by Cd and Zn treatments. Yeast expression assay showed SaMT2 significantly enhanced Cd tolerance and accumulation in yeast. Ectopic expression of SaMT2 in tobacco enhanced Cd and Zn tolerance and accumulation in both shoots and roots of the transgenic plants. The transgenic plants had higher antioxidant enzyme activities and accumulated less H2O2 than wild-type plants under Cd and Zn treatment. Thus, SaMT2 could significantly enhance Cd and Zn tolerance and accumulation in transgenic tobacco plants by chelating metals and improving antioxidant system.
authors.affiliation: MOE Key Laboratory of Environment Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
authors.affiliation: MOE Key Laboratory of Environment Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.affiliation: MOE Key Laboratory of Environment Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Shengke
authors.initials: S
authors.lastname: Tian
authors.affiliation: MOE Key Laboratory of Environment Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Lingli
authors.initials: L
authors.lastname: Lu
authors.affiliation: MOE Key Laboratory of Environment Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China.
authors.forename: M J I
authors.initials: MJ
authors.lastname: Shohag
authors.affiliation: MOE Key Laboratory of Environment Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Xiaoe
authors.initials: X
authors.lastname: Yang
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D002104:Cadmium / Q000378:metabolism*; D003545:Cysteine / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000502:physiology; D006861:Hydrogen Peroxide / Q000378:metabolism; D008668:Metallothionein / Q000378:metabolism*; D018517:Plant Roots / Q000378:metabolism; D018520:Plant Shoots / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000378:metabolism; D031963:Sedum / Q000378:metabolism*; D014026:Nicotiana / Q000378:metabolism*; D015003:Yeasts / Q000378:metabolism*; D015032:Zinc / Q000378:metabolism
chemical_list: D000975:Antioxidants; D002104:Cadmium; D008668:Metallothionein; D006861:Hydrogen Peroxide; D015032:Zinc; D003545:Cysteine