title: Genetic engineering of the biosynthesis of glycinebetaine leads to alleviate salt-induced potassium efflux and enhances salt tolerance in tomato plants.
abstract: Tomato (Solanum lycopersicum cv. 'Moneymaker') was transformed with the choline oxidase gene codA from Arthrobacter globiformis, which was modified to allow for targeting to both chloroplasts and the cytosol. Glycine betaine (GB) was accumulated in transformed plants, while no detectable GB was found in wild-type (WT) plants. Compared to WT plants, transgenic lines showed significantly higher photosynthetic rates (Pn) and antioxidant enzyme activities and lower reactive oxygen species (ROS) accumulation in the leaves when exposed to salt stress. Furthermore, compared with WT plants, K+efflux decreased and Na+efflux increased in roots of transgenic plants under salt stress; resulted in lower Na+/K+ratios in transgenic lines. The exogenous application of GB also significantly reduced NaCl-induced K+efflux and increased Na+efflux in WT plants. A qRT-PCR assay indicated that GB enhanced NaCl-induced expression of genes encoding the K+transporter, Na+/H+antiporter, and H+-ATPase. These results suggest that the enhanced salt tolerance conferred by codA in transgenic tomato plants might be due to the regulation of ion channel and transporters by GB, which would allow high potassium levels and low sodium levels to be maintained in transgenic plants under salt stress condition.
authors.affiliation: College of Life Science, State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, Shandong Agricultural University, Taian 271018, China.
authors.forename: Dandan
authors.initials: D
authors.lastname: Wei
authors.affiliation: College of Life Science, State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, Shandong Agricultural University, Taian 271018, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Zhang
authors.affiliation: College of Life Science, State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, Shandong Agricultural University, Taian 271018, China.
authors.forename: Cuicui
authors.initials: C
authors.lastname: Wang
authors.affiliation: College of Life Science, State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, Shandong Agricultural University, Taian 271018, China.
authors.forename: Qingwei
authors.initials: Q
authors.lastname: Meng
authors.affiliation: College of Life Science, State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, Shandong Agricultural University, Taian 271018, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Li
authors.affiliation: Department of Horticulture, ALS 4017, Oregon State University, Corvallis, OR 97331, USA.
authors.forename: Tony H H
authors.initials: THH
authors.lastname: Chen
authors.affiliation: College of Life Science, State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, Shandong Agricultural University, Taian 271018, China. Electronic address: xhyang@sdau.edu.cn.
authors.forename: Xinghong
authors.initials: X
authors.lastname: Yang
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D001622:Betaine / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant; D005818:Genetic Engineering / Q000379:methods*; D006859:Hydrogen / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D018551:Solanum lycopersicum / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D010788:Photosynthesis / Q000187:drug effects; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000502:physiology; D030821:Plants, Genetically Modified; D011188:Potassium / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D055049:Salt Tolerance / Q000187:drug effects* / Q000235:genetics; D036226:Seedlings / Q000187:drug effects / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology*; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics; D013481:Superoxides / Q000378:metabolism; D014170:Transformation, Genetic / Q000187:drug effects; D019076:Transgenes
chemical_list: D000975:Antioxidants; D012333:RNA, Messenger; D013481:Superoxides; D001622:Betaine; D012965:Sodium Chloride; D006859:Hydrogen; D012964:Sodium; D006861:Hydrogen Peroxide; D011188:Potassium; D002118:Calcium
keywords: Glycine betaine; Photosynthesis; Potassium flux; Salt stress; Tomato