title: Transgenic potato overproducing L-ascorbic acid resisted an increase in methylglyoxal under salinity stress via maintaining higher reduced glutathione level and glyoxalase enzyme activity.
abstract: Salt-tolerance was studied in transgenic potato. It was conferred by overexpression of ascorbate pathway enzyme (D-galacturonic acid reductase, GalUR). As genetic engineering of the GalUR gene in potato enhances its ascorbic acid content (L-AsA), and subsequently plants suffered minimal oxidative stress-induced damage, we now report on the comprehensive aptness of this engineering approach for enhanced salt tolerance in transgenic potato (Solanum tuberosum L. cv. Taedong Valley). Potatoes overexpressing GalUR grew and tuberized in continuous presence of 200 mM of NaCl. The transgenic plants maintained a higher reduced to oxidized glutathione (GSH:GSSG) ratio together with enhanced activity of glutathione dependent antioxidative and glyoxalase enzymes under salinity stress. The transgenics resisted an increase in methylglyoxal that increased radically in untransformed control plants under salinity stress. This is the first report of genetic engineering of ascorbate pathway gene in maintaining higher level of GSH homeostasis along with higher glyoxalase activity inhibiting the accumulation in methylglyoxal (a potent cytotoxic compound) under salt stress. These results suggested the engineering of ascorbate pathway enzymes as a major step towards developing salinity tolerant crop plants.
authors.affiliation: Department of Molecular Biotechnology, Konkuk University, Seoul, Korea Republic.
authors.forename: Chandrama Prakash
authors.initials: CP
authors.lastname: Upadhyaya
authors.forename: Jelli
authors.initials: J
authors.lastname: Venkatesh
authors.forename: Mayank Anand
authors.initials: MA
authors.lastname: Gururani
authors.forename: Leonid
authors.initials: L
authors.lastname: Asnin
authors.forename: Kavita
authors.initials: K
authors.lastname: Sharma
authors.forename: Hemavathi
authors.initials: H
authors.lastname: Ajappala
authors.forename: Se Won
authors.initials: SW
authors.lastname: Park
mesh_terms: D000429:Alcohol Oxidoreductases / Q000235:genetics / Q000378:metabolism; D001205:Ascorbic Acid / Q000378:metabolism*; D015870:Gene Expression; D005978:Glutathione / Q000378:metabolism*; D007791:Lactoylglutathione Lyase / Q000378:metabolism*; D064430:NAD (+) and NADP (+) Dependent Alcohol Oxidoreductases; D030821:Plants, Genetically Modified; D011765:Pyruvaldehyde / Q000633:toxicity*; D054712:Salinity; D011198:Solanum tuberosum / Q000235:genetics / Q000502:physiology*; D013312:Stress, Physiological
chemical_list: D011765:Pyruvaldehyde; D000429:Alcohol Oxidoreductases; D064430:NAD (+) and NADP (+) Dependent Alcohol Oxidoreductases; C477073:D-galacturonate reductase; D007791:Lactoylglutathione Lyase; D005978:Glutathione; D001205:Ascorbic Acid