Co-transforming bar and CsLEA enhanced tolerance to drought and salt stress in transgenic alfalfa (Medicago sativa L.)

• Published in: Biochemical and biophysical research communications 2016-03, Vol.472 (1), p.75-82
• Main Authors: Zhang, Jiyu, Duan, Zhen, Zhang, Daiyu, Zhang, Jianquan, Di, Hongyan, Wu, Fan, Wang, Yanrong
• Format: Article
• Language: English
• Subjects: Acclimatization; Alfalfa; Bar; biomass; CsLEA gene; drought; Drought and salt stress; drought tolerance; Droughts; gene overexpression; genes; Genes, Plant; grasses; herbicide resistance; Kengia; LEA; leaves; MDA; Medicago sativa; Medicago sativa - genetics; Medicago sativa - growth & development; Medicago sativa - physiology; osmotic stress; Phenotype; Plant Proteins - genetics; Plants, Genetically Modified; Recombinant Proteins - genetics; reverse transcriptase polymerase chain reaction; RWC; salinity; salt stress; salt tolerance; Salt-Tolerance - genetics; Salt-Tolerance - physiology; sodium; Stress, Physiological; SWC; toxicity; Transformation; Transformation, Genetic; transgenic plants; water content; water stress
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2016.02.067

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. •Alfalfa lines developed with tolerance to herbicide, drought, salt stress, which will facilitate its production in China.•The transgenic alfalfa plants could growth healthily at 200 mM NaCl.•The transgenic plants showed a relatively lower Na+ content and a higher relative water content during stresses.