Lhcb2 gene expression analysis in two ecotypes of Sedum alfredii subjected to Zn/Cd treatments with functional analysis of SaLhcb2 isolated from a Zn/Cd hyperaccumulator

The Lhcb2 gene from hyperaccumulator Sedum alfredii was up-regulated more than three-fold while the non-hyperaccumulator accumulated one or two-fold higher amount of the mRNA than control plants under different concentrations of Cd2+ for 24 h. Lhcb2 expression was up-regulated more than five-fold in a non-hyperaccumulator S. alfredii when exposed to 2 mu M Cd2+ or 50 mu M Zn2+ for 8 d and the hyperaccumulator had over two-fold more mRNA abundance than the control plants. Over-expression of SaLhcb2 increased the shoot biomass by 14-41% and the root biomass by 21-57% without Cd2+ treatment. Four transgenic tobacco lines (L5, L7, L10 and L11) possessed higher shoot biomass than WT plants with Cd2+. Four transgenic lines (L7, L8, L10 and L11) accumulated 6-35% higher Cd2+ amounts in shoots than the wild type plants.