title: OsTCTP, encoding a translationally controlled tumor protein, plays an important role in mercury tolerance in rice.
abstract: BACKGROUND
  Mercury (Hg) is not only a threat to public health but also a growth risk factor to plants, as it is readily accumulated by higher plants. Accumulation of Hg in plants disrupts many cellular-level functions and inhibits growth and development; however, the detoxification and tolerance mechanisms of plants to Hg stress are still not fully understood. Exposure to toxic Hg also occurs in some crops cultivated under anoxic conditions, such as rice (Oryza sativa L.), a model organism and one of the most important cultivated plants worldwide. In this study, we functionally characterized a rice translationally controlled tumor protein gene (Os11g43900, OsTCTP) involved in Hg stress tolerance.
  
  
  RESULTS
  OsTCTP was ubiquitously expressed in all examined plant tissues, especially in actively dividing and differentiating tissues, such as roots and nodes. OsTCTP was found to localize both the cytosol and the nucleus. OsTCTP was induced by mercuric chloride, cupric sulfate, abscisic acid, and hydrogen peroxide at the protein level in a time-dependent manner. Overexpression of OsTCTP potentiated the activities of several antioxidant enzymes, reduced the Hg-induced H2O2 levels, and promoted Hg tolerance in rice, whereas knockdown of OsTCTP produced opposite effects. And overexpression of OsTCTP did not prevent Hg absorption and accumulation in rice. We also demonstrated that Asn 48 and Asn 97 of OsTCTP amino acids were not the potential N-glycosylation sites.
  
  
  CONCLUSIONS
  Our results suggest that OsTCTP is capable of decreasing the Hg-induced reactive oxygen species (ROS), therefore, reducing the damage of ROS and enhancing the tolerance of rice plants to Hg stress. Thus, OsTCTP is a valuable gene for genetic engineering to improve rice performance under Hg contaminated paddy soils.
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China. zhqwang@zju.edu.cn.
authors.forename: Zhan Qi
authors.initials: ZQ
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China. gezi888@126.com.
authors.forename: Ge Zi
authors.initials: GZ
authors.lastname: Li
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China. gongqiaoqiao331@126.com.
authors.forename: Qiao Qiao
authors.initials: QQ
authors.lastname: Gong
authors.affiliation: College of Agronomy and Biotechnology, Zhejiang University, Hangzhou, 310058, China. guixinli@zju.edu.cn.
authors.forename: Gui Xin
authors.initials: GX
authors.lastname: Li
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China. sjzheng@zju.edu.cn.
authors.forename: Shao Jian
authors.initials: SJ
authors.lastname: Zheng
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D000222:Adaptation, Physiological / Q000187:drug effects / Q000235:genetics; D017398:Alternative Splicing / Q000187:drug effects / Q000235:genetics; D000975:Antioxidants / Q000378:metabolism; D003300:Copper / Q000633:toxicity; D018628:Gene Dosage; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant; D005978:Glutathione / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008628:Mercury / Q000633:toxicity*; D009154:Mutation; D012275:Oryza / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D010641:Phenotype; D010802:Phylogeny; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism; D010941:Plant Tumors / Q000235:genetics*; D030821:Plants, Genetically Modified; D014176:Protein Biosynthesis / Q000187:drug effects; D034622:RNA Interference / Q000187:drug effects; D017386:Sequence Homology, Amino Acid; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics; D040681:Structural Homology, Protein; D013347:Subcellular Fractions / Q000187:drug effects / Q000378:metabolism
chemical_list: D000975:Antioxidants; D010940:Plant Proteins; D000040:Abscisic Acid; D003300:Copper; D006861:Hydrogen Peroxide; D008628:Mercury; D005978:Glutathione