title: Overexpression of a protein disulfide isomerase-like protein from Methanothermobacter thermoautotrophicum enhances mercury tolerance in transgenic rice.
abstract: MTH1745, from thermophilic archaea Methanothermobacter thermoautotrophicum, is a protein disulfide isomerase-like protein (PDIL) with a chaperone function and disulfide isomerase activity. Mercuric cations have a high affinity for sulfhydryl groups and consequently inhibit plant growth. Disulfide compounds (e.g., copper-zinc superoxide dismutase, Cu/Zn SOD) and sulfhydryl compounds (e.g., glutathione, phytochelatins, and metallothioneins) play important roles in mercury (Hg) response. To study the relationship between Hg detoxification and PDILs, we overexpressed MTH1745 in Oryza sativa L. cv. Nipponbare by Agrobacterium-mediated transformation. The transgenic rice seedlings displayed Hg tolerance with obvious phenotypes and more effective photosynthesis compared to wild-type plants. Furthermore, lower levels of superoxide anion radicals, hydrogen peroxide, and malondialdehyde were observed in leaves or roots of transgenic plants. Antioxidant enzyme activities of superoxide dismutase and peroxidase were notably higher in transgenic seedlings under different concentrations of mercuric chloride. Moreover, increased content of non-protein thiols, reduced glutathione (GSH), and GSH/GSSG (GSSG, oxidized glutathione) ratio were also observed in the detoxification of Hg. These results indicated that heterologous expression of a PDIL from extremophiles in rice could protect the synthesis, increase stability of proteins, and enhance Hg tolerance in rice.
authors.affiliation: College of Life Sciences, Zhejiang University, Hangzhou 310058, People's Republic of China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Chen
authors.forename: Yanhui
authors.initials: Y
authors.lastname: Pan
authors.forename: Shanshan
authors.initials: S
authors.lastname: Wang
authors.forename: Yanfei
authors.initials: Y
authors.lastname: Ding
authors.forename: Weijun
authors.initials: W
authors.lastname: Yang
authors.forename: Cheng
authors.initials: C
authors.lastname: Zhu
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D001692:Biological Transport; D018525:Germination / Q000187:drug effects; D005978:Glutathione / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D015227:Lipid Peroxidation; D008628:Mercury / Q000032:analysis / Q000378:metabolism / Q000494:pharmacology*; D017013:Methanobacteriaceae / Q000201:enzymology* / Q000235:genetics; D012275:Oryza / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000502:physiology*; D010788:Photosynthesis / Q000187:drug effects / Q000235:genetics; D018515:Plant Leaves / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000502:physiology; D018517:Plant Roots / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000502:physiology; D018526:Plant Transpiration; D030821:Plants, Genetically Modified; D019704:Protein Disulfide-Isomerases / Q000235:genetics* / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000502:physiology; D012639:Seeds / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000502:physiology; D013312:Stress, Physiological; D013438:Sulfhydryl Compounds / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism
chemical_list: D000975:Antioxidants; D013438:Sulfhydryl Compounds; D013481:Superoxides; D006861:Hydrogen Peroxide; D019704:Protein Disulfide-Isomerases; D008628:Mercury; D005978:Glutathione