title: Expression of the rgMT gene, encoding for a rice metallothionein-like protein in Saccharomyces cerevisiae and Arabidopsis thaliana.
abstract: Metallothioneins (MTs) are cysteine-rich proteins of low molecular weight with many attributed functions, such as providing protection against metal toxicity, being involved in regulation of metal ions uptake that can impact plant physiology and providing protection against oxidative stress. However, the precise function of the metallothionein-like proteins such as the one coded for rgMT gene isolated from rice (Oryza sativa L.) is not completely understood. The whole genome analysis of rice (O. sativa) showed that the rgMT gene is homologue to the Os11g47809 on chromosome 11 of O. sativa sp. japonica genome. This study used the rgMT coding sequence to create transgenic lines to investigate the subcellular localization of the protein, as well as the impact of gene expression in yeast (Saccharomyces cerevisiae) and Arabidopsis thaliana under heavy metal ion, salt and oxidative stresses. The results indicate that the rgMT gene was expressed in the cytoplasm of transgenic cells. Yeast cells transgenic for rgMT showed vigorous growth compared to the nontransgenic controls when exposed to 7 mM CuCl2, 10 mM FeCl2, 1 M NaCl, 24 mM NaHCO3 and 3.2 mM H2O2, but there was no significant difference for other stresses tested. Similarly, Arabidopsis transgenic for rgMT displayed significantly improved seed germination rates over that of the control when the seeds were stressed with 100 μM CuCl2 or 1 mM H2O2. Increased biomass was observed in the presence of 100 μM CuCl2, 220 μM FeCl2, 3 mM Na2CO3, 5 mM NaHCO3 or 1 mM H2O2. These results indicate that the expression of the rice rgMT gene in transgenic yeast and Arabidopsis is implicated in improving their tolerance for certain salt and peroxide stressors.
authors.affiliation: Key Laboratory of Saline-alkali Vegetation Ecology Restoration in Oil Field (SAVER),Ministry of Education, Alkali Soil Natural Environmental Science Center (ASNESC), Northeast Forestry University, Harbin 150040, People's Republic of China. xw-wang@tamu.edu.
authors.forename: Shumei
authors.initials: S
authors.lastname: Jin
authors.forename: Dan
authors.initials: D
authors.lastname: Sun
authors.forename: Ji
authors.initials: J
authors.lastname: Wang
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.forename: Xinwang
authors.initials: X
authors.lastname: Wang
authors.forename: Shenkui
authors.initials: S
authors.lastname: Liu
mesh_terms: D017360:Arabidopsis / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008668:Metallothionein / Q000096:biosynthesis* / Q000235:genetics; D012275:Oryza / Q000235:genetics*; D018384:Oxidative Stress / Q000235:genetics*; D030821:Plants, Genetically Modified; D012441:Saccharomyces cerevisiae / Q000235:genetics; D012492:Salts / Q000494:pharmacology
chemical_list: D012492:Salts; D008668:Metallothionein; D006861:Hydrogen Peroxide