title: Overexpression of an alfalfa GDP-mannose 3, 5-epimerase gene enhances acid, drought and salt tolerance in transgenic Arabidopsis by increasing ascorbate accumulation.
abstract: GDP-mannose 3', 5'-epimerase (GME) catalyses the conversion of GDP-D-mannose to GDP-L-galactose, an important step in the ascorbic acid (ascorbic acid) biosynthetic pathway in higher plants. In this study, a novel cDNA fragment (MsGME) encoding a GME protein was isolated and characterised from alfalfa (Medicago sativa). An expression analysis confirmed that MsGME expression was induced by salinity, PEG and acidity stresses. MsGME overexpression in Arabidopsis enhanced tolerance of the transgenic plants to salt, drought and acid. Real-time PCR analysis revealed that the transcript levels of GDP-D-mannose pyrophosphorylase (GMP), L-galactose-phosphate 1-P phosphatase (GP) and GDP-L-galactose phosphorylase (GGP) were increased in transgenic Arabidopsis (T3 generation). Moreover, the ascorbate content was increased in transgenic Arabidopsis. Our results suggest that MsGME can effectively enhance tolerance of transgenic Arabidopsis to acid, drought and salt by increasing ascorbate accumulation.
authors: State Key Laboratory of Grassland Agro-ecosystems, School of Pastoral Agricultural Science and Technology, Lanzhou University, Lanzhou, 730020, People's Republic of China, ma-lichao@163.com.
authors: Lichao
authors: L
authors: Ma
authors: Yanrong
authors: Y
authors: Wang
authors: Wenxian
authors: W
authors: Liu
authors: Zhipeng
authors: Z
authors: Liu
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D001205:Ascorbic Acid / Q000032:analysis / Q000378:metabolism*; D002238:Carbohydrate Epimerases / Q000235:genetics / Q000378:metabolism*; D000455:Medicago sativa / Q000201:enzymology* / Q000235:genetics; D053858:Metabolic Networks and Pathways; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D055049:Salt Tolerance; D055051:Salt-Tolerant Plants / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D013312:Stress, Physiological / Q000235:genetics*
chemical_list: D010940:Plant Proteins; D011994:Recombinant Proteins; D002238:Carbohydrate Epimerases; C019192:GDPmannose 3,5-epimerase; D001205:Ascorbic Acid