【摘要】 类胡萝卜素是一类重要的天然色素,在植物生长发育和抵御逆境的过程中起着重要作用.番茄红素ε-环化酶是类胡萝卜素合成的关键酶,催化番茄红素向α类胡萝卜素的转化.本文以烟草为材料,通过转基因手段分别获得了烟草Ntε-LCY基因的过量表达和基因沉默株系.表型分析结果显示:与野生型植株相比,Ntε-LCY过量表达植株的抗旱能力显著降低,而Ntε-LCY表达沉默株系的抗旱能力明显增强.生理指标测定结果显示:Ntε-LCY过量表达植株叶片的失水效率、活性氧(ROS)含量显著高于野生型植株,而Ntε-LCY沉默株系的生理指标值明显低于野生型植株.这些生理指标值的改变趋势与植株ABA含量的变化趋势相反,表明Ntε-LCY基因可能通过调控ABA含量,影响植株的失水效率和ROS累积,进而调控植物的抗旱性.更多还原

【Abstract】 Carotenoids are crucial pigments functioning in the growth and adaption against environmental stresses in plants. Lycopene ε-cyclase(ε-LCY) is a key enzyme catalyzing the synthesis of α carotenoid. In this study, the authors generated Ntε-LCY overproducing and expressing silencing lines in tobacco. Phenotypic analysis shows that Ntε-LCY overproducing plants are more sensitive to drought stress compared with wild-type plants, whereas Ntε-LCY silencing plants are more tolerant. Consistently, the water loss rate and reactive oxygen species(ROS) content are significantly higher in Ntε-LCY overproducing plants and lower in Ntε-LCY silencing plants than wild-type plants. These physiological parameters changes seem to be related to the altered abscisic acid(ABA) by Ntε-LCY manipulation in plants. A significant increase is in Ntε-LCY overproducing plants and an observed decrease is in Ntε-LCY silencing plants compared with wild-type plants. Taken together, the results indicate that Ntε-LCY may affect ABA synthesis and in turn influence water loss and ROS accumulation, finally modulating the drought tolerance in tobacco.更多还原