PDF(Pubmed)
Abstract：
BACKGROUND: Lycopene epsilon-cyclase (ε-LCY) is a key enzyme in the carotenoid biosynthetic pathway (CBP) of higher plants. In previous work, we cloned two Ntε-LCY genes from allotetraploid tobacco (Nicotiana tabacum), Ntε-LCY2 and Ntε-LCY1, and demonstrated the overall effect of Ntε-LCY genes on carotenoid biosynthesis and stress resistance. However, their genetic and functional characteristics require further research in polyploid plants.
RESULTS: Here, we used CRISPR/Cas9 to obtain Ntε-LCY2 and Ntε-LCY1 mutants in allotetraploid N.tabacum K326. Ntε-LCY2 and Ntε-LCY1 had similar promoter cis-acting elements, including light-responsive elements. The Ntε-LCY genes were expressed in roots, stems, leaves, flowers, and young fruit, and their highest expression levels were found in leaves. Ntε-LCY2 and Ntε-LCY1 genes responded differently to normal light and high light stress. Both the Ntε-LCY2 and the Ntε-LCY1 mutants had a more rapid leaf growth rate, especially ntε-lcy2-1. The expression levels of CBP genes were increased in the ntε-lcy mutants, and their total carotenoid content was higher. Under both normal light and high light stress, the ntε-lcy mutants had higher photosynthetic capacities and heat dissipation levels than the wild type, and this was especially true of ntε-lcy2-1. The reactive oxygen species content was lower in leaves of the ntε-lcy mutants.
CONCLUSIONS: In summary, the expression patterns and biological functions of the Ntε-LCY genes Ntε-LCY1 and Ntε-LCY2 differed in several respects. The mutation of Ntε-LCY2 was associated with a greater increase in the content of chlorophyll and various carotenoid components, and it enhanced the stress resistance of tobacco plants under high light.
RESULTS: Here, we used CRISPR/Cas9 to obtain Ntε-LCY2 and Ntε-LCY1 mutants in allotetraploid N.tabacum K326. Ntε-LCY2 and Ntε-LCY1 had similar promoter cis-acting elements, including light-responsive elements. The Ntε-LCY genes were expressed in roots, stems, leaves, flowers, and young fruit, and their highest expression levels were found in leaves. Ntε-LCY2 and Ntε-LCY1 genes responded differently to normal light and high light stress. Both the Ntε-LCY2 and the Ntε-LCY1 mutants had a more rapid leaf growth rate, especially ntε-lcy2-1. The expression levels of CBP genes were increased in the ntε-lcy mutants, and their total carotenoid content was higher. Under both normal light and high light stress, the ntε-lcy mutants had higher photosynthetic capacities and heat dissipation levels than the wild type, and this was especially true of ntε-lcy2-1. The reactive oxygen species content was lower in leaves of the ntε-lcy mutants.
CONCLUSIONS: In summary, the expression patterns and biological functions of the Ntε-LCY genes Ntε-LCY1 and Ntε-LCY2 differed in several respects. The mutation of Ntε-LCY2 was associated with a greater increase in the content of chlorophyll and various carotenoid components, and it enhanced the stress resistance of tobacco plants under high light.
摘要：
背景：番茄红素ε-环化酶（ε-LCY）是高等植物类胡萝卜素生物合成途径（CBP）中的关键酶。在以前的工作中,我们从异源四倍体烟草（烟草）中克隆了两个Ntε-LCY基因，Ntε-LCY2和Ntε-LCY1，并证明了Ntε-LCY基因对类胡萝卜素生物合成和胁迫抗性的总体影响。然而,它们的遗传和功能特性需要在多倍体植物中进一步研究。
结果：这里，我们使用CRISPR/Cas9在同种四倍体烟草K326中获得了Ntε-LCY2和Ntε-LCY1突变体。Ntε-LCY2和Ntε-LCY1具有相似的启动子顺式作用元件,包括光响应元素。Ntε-LCY基因在根中表达,茎,叶子,鲜花,和年轻的水果，它们的最高表达水平在叶片中发现。Ntε-LCY2和Ntε-LCY1基因对正常光和高光胁迫的反应不同。Ntε-LCY2和Ntε-LCY1突变体的叶片生长速度都较快,尤其是ntε-lcy2-1。在ntε-lcy突变体中CBP基因的表达水平增加，它们的类胡萝卜素总含量较高。在正常光和高光应力下，ntε-lcy突变体比野生型具有更高的光合能力和散热水平，ntε-lcy2-1尤其如此。ntε-lcy突变体叶片中的活性氧含量较低。
结论：总之，Ntε-LCY基因Ntε-LCY1和Ntε-LCY2的表达模式和生物学功能在几个方面有所不同。Ntε-LCY2的突变与叶绿素和各种类胡萝卜素成分含量的增加有关,增强了烟草植株在强光下的抗逆性。
结果：这里，我们使用CRISPR/Cas9在同种四倍体烟草K326中获得了Ntε-LCY2和Ntε-LCY1突变体。Ntε-LCY2和Ntε-LCY1具有相似的启动子顺式作用元件,包括光响应元素。Ntε-LCY基因在根中表达,茎,叶子,鲜花,和年轻的水果，它们的最高表达水平在叶片中发现。Ntε-LCY2和Ntε-LCY1基因对正常光和高光胁迫的反应不同。Ntε-LCY2和Ntε-LCY1突变体的叶片生长速度都较快,尤其是ntε-lcy2-1。在ntε-lcy突变体中CBP基因的表达水平增加，它们的类胡萝卜素总含量较高。在正常光和高光应力下，ntε-lcy突变体比野生型具有更高的光合能力和散热水平，ntε-lcy2-1尤其如此。ntε-lcy突变体叶片中的活性氧含量较低。
结论：总之，Ntε-LCY基因Ntε-LCY1和Ntε-LCY2的表达模式和生物学功能在几个方面有所不同。Ntε-LCY2的突变与叶绿素和各种类胡萝卜素成分含量的增加有关,增强了烟草植株在强光下的抗逆性。
