title: A novel thylakoid ascorbate peroxidase from Jatrophacurcas enhances salt tolerance in transgenic tobacco.
abstract: Ascorbate peroxidase (APX) plays an important role in the metabolism of hydrogen peroxide in higher plants. In the present study, a novel APX gene (JctAPX) was cloned from Jatropha curcas L. The deduced amino acid sequence was similar to that of APX of some other plant species. JctAPX has a chloroplast transit peptide and was localized to the chloroplasts by analysis with a JctAPX-green fluorescent protein (GFP) fusion protein. Quantitative polymerase chain reaction (qPCR) analysis showed that JctAPX was constitutively expressed in different tissues from J. curcas and was upregulated by NaCl stress. To characterize its function in salt tolerance, the construct p35S: JctAPX was created and successfully introduced into tobacco by Agrobacterium-mediated transformation. Compared with wild type (WT), the transgenic plants exhibited no morphological abnormalities in the no-stress condition. However, under 200 mM NaCl treatment, JctAPX over-expressing plants showed increased tolerance to salt during seedling establishment and growth. In addition, the transgenic lines showed higher chlorophyll content and APX activity, which resulted in lower H2O2 content than WT when subjected to 400 mM NaCl stress. These results suggest that the increased APX activity in the chloroplasts from transformed plants increased salt tolerance by enhancing reactive oxygen species (ROS)-scavenging capacity under short-term NaCl stress conditions.
authors.forename: Zhibin
authors.initials: Z
authors.lastname: Liu
authors.forename: Han
authors.initials: H
authors.lastname: Bao
authors.forename: Jin
authors.initials: J
authors.lastname: Cai
authors.forename: Jun
authors.initials: J
authors.lastname: Han
authors.affiliation: Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610064, Sichuan, China. zhoulr@mail.ubc.ca.
authors.forename: Lirong
authors.initials: L
authors.lastname: Zhou
mesh_terms: D000199:Actins / Q000378:metabolism; D000595:Amino Acid Sequence; D060387:Ascorbate Peroxidases / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D002734:Chlorophyll / Q000378:metabolism; D002736:Chloroplasts / Q000201:enzymology; D003001:Cloning, Molecular; D006861:Hydrogen Peroxide / Q000378:metabolism; D031286:Jatropha / Q000201:enzymology*; D015227:Lipid Peroxidation; D008969:Molecular Sequence Data; D010802:Phylogeny; D018515:Plant Leaves / Q000378:metabolism; D010940:Plant Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D036226:Seedlings / Q000201:enzymology; D016415:Sequence Alignment; D012965:Sodium Chloride / Q000494:pharmacology*; D020524:Thylakoids / Q000378:metabolism; D014026:Nicotiana / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism
chemical_list: D000199:Actins; D010940:Plant Proteins; D002734:Chlorophyll; D012965:Sodium Chloride; D006861:Hydrogen Peroxide; D060387:Ascorbate Peroxidases