title: BcPMI2, isolated from non-heading Chinese cabbage encoding phosphomannose isomerase, improves stress tolerance in transgenic tobacco.
abstract: Phosphomannose isomerase (PMI) is an enzyme that catalyses the first step of the L-galactose pathway for ascorbic acid (AsA) biosynthesis in plants. To clarify the physiological roles of PMI in AsA biosynthesis, the cDNA sequence of PMI was cloned from non-heading Chinese cabbage (Brassica campestris ssp. chinensis Makino) and overexpressed in tobacco transformed with Agrobacterium tumefaciens. The AsA and soluble sugar contents were lower in 35S::BcPMI2 tobacco than in wild-type tobacco. However, the AsA level in BcPMI2-overexpressing plants under stress was significantly increased. The T1 seed germination rate of transgenic plants was higher than that of wild-type plants under NaCl or H2O2 treatment. Meanwhile, transgenic plants showed higher tolerance than wild-type plants. This finding implied that BcPMI2 overexpression improved AsA biosynthetic capability and accumulation, and evidently enhanced tolerance to oxidative and salt stress, although the AsA level was lower in transgenic tobacco than in wild-type tobacco under normal condition.
authors.affiliation: Horticultural Department, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Xuehua
authors.initials: X
authors.lastname: Wang
authors.forename: Shuo
authors.initials: S
authors.lastname: Zhang
authors.forename: Die
authors.initials: D
authors.lastname: Hu
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Zhao
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Tongkun
authors.initials: T
authors.lastname: Liu
authors.forename: Jianjun
authors.initials: J
authors.lastname: Wang
authors.forename: Xilin
authors.initials: X
authors.lastname: Hou
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
mesh_terms: D000220:Adaptation, Biological / Q000235:genetics*; D000595:Amino Acid Sequence; D001205:Ascorbic Acid / Q000378:metabolism; D001937:Brassica / Q000235:genetics* / Q000378:metabolism*; D003001:Cloning, Molecular; D016000:Cluster Analysis; D015870:Gene Expression; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D018525:Germination / Q000235:genetics; D008359:Mannose-6-Phosphate Isomerase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D018384:Oxidative Stress; D010544:Peroxidases / Q000378:metabolism; D030821:Plants, Genetically Modified; D055049:Salt Tolerance / Q000235:genetics; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013312:Stress, Physiological / Q000235:genetics*; D013482:Superoxide Dismutase / Q000378:metabolism; D014026:Nicotiana / Q000235:genetics* / Q000378:metabolism*
chemical_list: D010544:Peroxidases; D013482:Superoxide Dismutase; D008359:Mannose-6-Phosphate Isomerase; D001205:Ascorbic Acid