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外文期刊>Frontiers in Plant Science
>Co-transforming bar and CsALDH Genes Enhanced Resistance to Herbicide and Drought and Salt Stress in Transgenic Alfalfa ( Medicago sativa L.)
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Co-transforming bar and CsALDH Genes Enhanced Resistance to Herbicide and Drought and Salt Stress in Transgenic Alfalfa ( Medicago sativa L.)
Drought and high salinity are two major abiotic factors that restrict the productivity of alfalfa. By application of the Agrobacterium - mediated transformation method, an oxidative responsive gene, CsALDH12A1 , from the desert grass Cleistogenes songorica together with the bar gene associated with herbicide resistance, were co-transformed into alfalfa ( Medicago sativa L.). From the all 90 transformants, 16 were positive as screened by spraying 1 mL L~(-1)10% Basta solution and molecularly diagnosis using PCR. Real-time PCR analysis indicated that drought and salt stress induced high CsALDH expression in the leaves of the transgenic plants. The CsALDH expression levels under drought (15 d) and salt stress (200 mM NaCl) were 6.11 and 6.87 times higher than in the control plants, respectively. In comparison to the WT plants, no abnormal phenotypes were observed among the transgenic plants, which showed significant enhancement of tolerance to 15 d of drought and 10 d of salinity treatment. Evaluation of the physiological and biochemical indices during drought and salt stress of the transgenic plants revealed relatively lower Na~(+)content and higher K~(+)content in the leaves relative to the WT plants, a reduction of toxic on effects and maintenance of osmotic adjustment. In addition, the transgenic plants could maintain a higher relative water content level, higher shoot biomass, fewer changes in the photosystem, decreased membrane injury, and a lower level of osmotic stress. These results indicate that the co-expression of the introduced bar and CsALDH genes enhanced the herbicide, drought and salt tolerance of alfalfa and therefore can potentially be used as a novel genetic resource for the future breeding programs to develop new cultivars.
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机译：干旱和高盐度是限制苜蓿生产力的两个主要非生物因素。通过农杆菌介导的转化方法，将来自荒漠草Cleistogenes songorica的氧化反应基因CsALDH12A1与与除草剂抗性相关的bar基因一起共转化为苜蓿（Medicago sativa L.）。在全部90个转化子中，通过喷洒1 mL L〜（-1）10％Basta溶液筛选并使用PCR进行分子诊断，筛选出16个阳性。实时PCR分析表明干旱和盐胁迫诱导了转基因植物叶片中高CsALDH表达。干旱（15 d）和盐胁迫（200 mM NaCl）下的CsALDH表达水平分别比对照植物高6.11倍和6.87倍。与野生型植物相比，在转基因植物中未观察到异常表型，这表明对干旱15 d和盐分处理10 d的耐受性显着提高。对转基因植物干旱和盐胁迫过程中的生理生化指标的评估表明，与野生型植物相比，叶片中Na〜（+）含量相对较低，而K〜（+）含量较高，毒性和维持效果均得到降低渗透调节。另外，转基因植物可以维持较高的相对水分含量，较高的枝条生物量，较少的光系统变化，减少的膜损伤和较低的渗透胁迫水平。这些结果表明，引入的bar和CsALDH基因的共表达增强了苜蓿的除草剂，干旱和盐分耐受性，因此可以潜在地用作未来育种计划以开发新品种的新型遗传资源。
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