title: Ectopic expression of wheat expansin gene TaEXPA2 improved the salt tolerance of transgenic tobacco by regulating Na+/K+and antioxidant competence.
abstract: High salinity is one of the most serious environmental stresses that limit crop growth. Expansins are cell wall proteins that regulate plant development and abiotic stress tolerance by mediating cell wall expansion. We studied the function of a wheat expansin gene, TaEXPA2, in salt stress tolerance by overexpressing it in tobacco. Overexpression of TaEXPA2 enhanced the salt stress tolerance of transgenic tobacco plants as indicated by the presence of higher germination rates, longer root length, more lateral roots, higher survival rates and more green leaves under salt stress than in the wild type (WT). Further, when leaf disks of WT plants were incubated in cell wall protein extracts from the transgenic tobacco plants, their chlorophyll content was higher under salt stress, and this improvement from TaEXPA2 overexpression in transgenic tobacco was inhibited by TaEXPA2 protein antibody. The water status of transgenic tobacco plants was improved, perhaps by the accumulation of osmolytes such as proline and soluble sugar. TaEXPA2-overexpressing tobacco lines exhibited lower Na+but higher K+accumulation than WT plants. Antioxidant competence increased in the transgenic plants because of the increased activity of antioxidant enzymes. TaEXPA2 protein abundance in wheat was induced by NaCl, and ABA signaling was involved. Gene expression regulation was involved in the enhanced salt stress tolerance of the TaEXPA2 transgenic plants. Our results suggest that TaEXPA2 overexpression confers salt stress tolerance on the transgenic plants, and this is associated with improved water status, Na+/K+homeostasis, and antioxidant competence. ABA signaling participates in TaEXPA2-regulated salt stress tolerance.
authors.affiliation: State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, P. R. China.
authors.forename: Yanhui
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Plastic Surgery Institute of Weifang Medical University, Weifang, P. R. China.
authors.forename: Yangyang
authors.initials: Y
authors.lastname: Han
authors.affiliation: State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, P. R. China.
authors.forename: Xiangzhu
authors.initials: X
authors.lastname: Kong
authors.affiliation: State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, P. R. China.
authors.forename: Hanhan
authors.initials: H
authors.lastname: Kang
authors.affiliation: State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, P. R. China.
authors.forename: Yuanqing
authors.initials: Y
authors.lastname: Ren
authors.affiliation: State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, P. R. China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D002734:Chlorophyll / Q000378:metabolism; D000066630:Ectopic Gene Expression; D018506:Gene Expression Regulation, Plant; D018525:Germination; D018515:Plant Leaves / Q000166:cytology / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000166:cytology / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D030821:Plants, Genetically Modified; D011188:Potassium / Q000378:metabolism; D055049:Salt Tolerance; D012964:Sodium / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology; D013312:Stress, Physiological; D014026:Nicotiana / Q000166:cytology / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D014908:Triticum / Q000166:cytology / Q000187:drug effects / Q000235:genetics* / Q000502:physiology
chemical_list: D000975:Antioxidants; D010940:Plant Proteins; D002734:Chlorophyll; D012965:Sodium Chloride; D012964:Sodium; D011188:Potassium