Co-transforming bar and CsALDH Genes Enhanced Resistance to Herbicide and Drought and Salt Stress in Transgenic Alfalfa (Medicago sativa L.).
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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DOI：
10.3389/fpls.2015.01115
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发表时间：
2015
影响因子：
5.6
通讯作者：
Wang Y
中科院分区：
文献类型：
--
作者：
Duan Z;Zhang D;Zhang J;Di H;Wu F;Hu X;Meng X;Luo K;Zhang J;Wang Y
干旱和高盐度是限制苜蓿生产力的两个主要非生物因素。应用农杆菌介导转化方法，将来自沙漠草Cleistogenes Songorica的氧化响应基因CsALDH12A1与除草剂抗性相关的bar基因共转化到苜蓿（Medicago sativa L.）中。在所有90个转化体中，通过喷洒1mL L-1 10%Basta溶液并使用PCR进行分子诊断筛选出16个呈阳性。实时PCR分析表明干旱和盐胁迫诱导转基因植物叶片中CsALDH高表达。干旱（15 d）和盐胁迫（200 mM NaCl）下CsALDH表达水平分别是对照植物的6.11和6.87倍。与WT植物相比，转基因植物未观察到异常表型，对15 d干旱和10 d盐度处理的耐受性显着增强。对转基因植物在干旱和盐胁迫期间的生理生化指标的评价显示，相对于野生型植物，其叶片中Na+含量相对较低，K+含量较高，毒性作用降低，渗透调节得以维持。此外，转基因植物可以保持较高的相对含水量水平、较高的芽生物量、较少的光系统变化、减少的膜损伤和较低水平的渗透胁迫。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、干旱和盐耐受性，因此有可能用作未来育种计划开发新品种的新型遗传资源。
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.