title: Co-transforming bar and CsLEA enhanced tolerance to drought and salt stress in transgenic alfalfa (Medicago sativa L.).
abstract: Drought and high salinity are two major abiotic factors that restrict alfalfa productivity. A dehydrin protein, CsLEA, from the desert grass Cleistogenes songorica was transformed into alfalfa (Medicago sativa L.) via Agrobacterium-mediated transformation using the bar gene as a selectable marker, and the drought and salt stress tolerances of the transgenic plants were assessed. Thirty-nine of 119 transformants were positive, as screened by Basta, and further molecularly authenticated using PCR and RT-PCR. Phenotype observations revealed that the transgenic plants grew better than the wild-type (WT) plants after 15d of drought stress and 10d of salt stress: the leaves of WT alfalfa turned yellow, whereas the transgenic alfalfa leaves only wilted; after rewatering, the transgenic plants returned to a normal state, though the WT plants could not be restored. Evaluation of physiologic and biochemical indices during drought and salt stresses showed a relatively lower Na(+) content in the leaves of the transgenic plants, which would reduce toxic ion effects. In addition, the transgenic plants were able to maintain a higher relative water content (RWC), higher shoot biomass, fewer photosystem changes, decreased membrane injury, and a lower level of osmotic stress injury. These results demonstrate that overexpression of the CsLEA gene can enhance the drought and salt tolerance of transgenic alfalfa; in addition, carrying the bar gene in the genome may increase herbicide resistance.
authors.affiliation: State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, China.
authors.forename: Jiyu
authors.initials: J
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Duan
authors.affiliation: State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, China.
authors.forename: Daiyu
authors.initials: D
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, China.
authors.forename: Jianquan
authors.initials: J
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, China.
authors.forename: Hongyan
authors.initials: H
authors.lastname: Di
authors.affiliation: State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, China.
authors.forename: Fan
authors.initials: F
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, China. Electronic address: yrwang@lzu.edu.cn.
authors.forename: Yanrong
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000064:Acclimatization; D055864:Droughts; D017343:Genes, Plant; D000455:Medicago sativa / Q000235:genetics* / Q000254:growth & development / Q000502:physiology*; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics; D030821:Plants, Genetically Modified; D011994:Recombinant Proteins / Q000235:genetics; D055049:Salt Tolerance / Q000235:genetics* / Q000502:physiology; D013312:Stress, Physiological; D014170:Transformation, Genetic
chemical_list: D010940:Plant Proteins; D011994:Recombinant Proteins; C070556:dehydrin proteins, plant
keywords: Alfalfa; Bar; CsLEA gene; Drought and salt stress; Transformation