Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/86484
標題: Transgenic Arabidopsis expressing osmolyte glycine betaine synthesizing enzymes from halophilic methanogen promote tolerance to drought and salt stress
作者: Lai, Shu-Jung
Lai, Mei-Chin
Lee, Ren-Jye
Chen, Yu-Hsuan
Yen, Hungchen Emilie
關鍵字: Arabidopsis;Archaeal Proteins;Betaine;Gene Expression Regulation, Enzymologic;Gene Expression Regulation, Plant;Methanosarcinaceae;Plants, Genetically Modified;Salt-Tolerance;Sodium Chloride;Stress, Physiological;Water
Project: Plant Molecular Biology, Volume 85, Issue 4-5, Page(s) 429-441.
摘要: 
Glycine betaine (betaine) has the highest cellular osmoprotective efficiency which does not accumulate in most glycophytes. The biosynthetic pathway for betaine in higher plants is derived from the oxidation of low-accumulating metabolite choline that limiting the ability of most plants to produce betaine. Halophilic methanoarchaeon Methanohalophilus portucalensis FDF1(T) is a model anaerobic methanogen to study the acclimation of water-deficit stresses which de novo synthesize betaine by the stepwise methylation of glycine, catalyzed by glycine sarcosine N-methyltransferase (GSMT) and sarcosine dimethylglycine N-methyltransferase. In this report, genes encoding these betaine biosynthesizing enzymes, Mpgsmt and Mpsdmt, were introduced into Arabidopsis. The homozygous Mpgsmt (G), Mpsdmt (S), and their cross, Mpgsmt and Mpsdmt (G × S) plants showed increased accumulation of betaine. Water loss from detached leaves was slower in G, S, and G × S lines than wild-type (WT). Pot-grown transgenic plants showed better growth than WT after 9 days of withholding water or irrigating with 300 mM NaCl. G, S, G × S lines also maintained higher relative water content and photosystem II activity than WT under salt stress. This suggests heterologously expressed Mpgsmt and Mpsdmt could enhance tolerance to drought and salt stress in Arabidopsis. We also found a twofold increase in quaternary ammonium compounds in salt-stressed leaves of G lines, presumably due to the activation of GSMT activity by high salinity. This study demonstrates that introducing stress-activated enzymes is a way of avoiding the divergence of primary metabolites under normal growing conditions, while also providing protection in stressful environments.
URI: http://hdl.handle.net/11455/86484
ISSN: 0167-4412
1573-5028
1573-5028
DOI: 10.1007/s11103-014-0195-8
Appears in Collections:生命科學系所

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