title: Enhancement of spermidine content and antioxidant capacity in transgenic pear shoots overexpressing apple spermidine synthase in response to salinity and hyperosmosis.
abstract: In our previous work, an apple spermidine synthase (SPDS)-overexpressing transgenic European pear (Pyrus communis L. 'Ballad'), line no. 32 (#32), demonstrated attenuated susceptibility to stress treatment. In the current paper, changes in enzymatic and non-enzymatic antioxidant capacity of the transgenic pear (line #32) were investigated in response to NaCl or mannitol stress. Under non-stressed conditions (before stress treatment), spermidine (Spd) contents and SPDS activity of line #32 were higher than those of the non-transformant (wild type). However, no significant differences were detected between line #32 and the wild type as regards contents of malondialdehyde (MDA) and H2O2, and activities of antioxidant enzymes like superoxide dismutase (SOD), ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR) and glutathione reductase (GR). When exposed to NaCl or mannitol stress, both the wild type and line #32 exhibited accumulation of Spd with the latter accumulating more. The transgenic line contained higher antioxidant enzyme activities, less MDA and H2O2 than the wild, implying it suffered from less injury. These results suggested that increase of Spd content in the transgenic line could, at least in part, lead to enhancing enzymatic and non-enzymatic antioxidant capacity.
authors.affiliation: National Institute of Fruit Tree Science, Tsukuba, Ibaraki 305-8605, Japan.
authors.forename: Lixiong
authors.initials: L
authors.lastname: He
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Ban
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Inoue
authors.forename: Narumi
authors.initials: N
authors.lastname: Matsuda
authors.forename: Jihong
authors.initials: J
authors.lastname: Liu
authors.forename: Takaya
authors.initials: T
authors.lastname: Moriguchi
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D006861:Hydrogen Peroxide / Q000378:metabolism; D008315:Malondialdehyde / Q000378:metabolism; D027845:Malus / Q000201:enzymology* / Q000235:genetics; D009997:Osmotic Pressure; D018520:Plant Shoots / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D030821:Plants, Genetically Modified; D011073:Polyamines / Q000378:metabolism; D011392:Proline / Q000378:metabolism; D031989:Pyrus / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D012965:Sodium Chloride / Q000494:pharmacology*; D013095:Spermidine / Q000378:metabolism*; D011436:Spermidine Synthase / Q000235:genetics / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D011073:Polyamines; D012965:Sodium Chloride; D008315:Malondialdehyde; D011392:Proline; D006861:Hydrogen Peroxide; D011436:Spermidine Synthase; D013095:Spermidine