Cloning of the Lycopene β-cyclase Gene in Nicotiana tabacum and Its Overexpression Confers Salt and Drought Tolerance.
Cloning of the Lycopene β-cyclase Gene in Nicotiana tabacum and Its Overexpression Confers Salt and Drought Tolerance.
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DOI：
10.3390/ijms161226243
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发表时间：
2015-12-21
影响因子：
5.6
通讯作者：
Wang R
中科院分区：
文献类型：
--
作者：
Shi Y;Guo J;Zhang W;Jin L;Liu P;Chen X;Li F;Wei P;Li Z;Li W;Wei C;Zheng Q;Chen Q;Zhang J;Lin F;Qu L;Snyder JH;Wang R
类胡萝卜素是植物中重要的色素，在植物生长和植物对环境胁迫的反应中起着至关重要的作用。番茄红素β环化酶（β-LCY）位于类胡萝卜素生物合成途径的分支点，催化番茄红素环化。本文克隆了烟草β-LCY基因，命名为Ntβ-LCY 1，并对其功能进行了分析。Ntβ-LCY 1基因在叶片中有较强的表达，盐、干旱和外源脱落酸对Ntβ-LCY 1基因的表达有明显的诱导作用。Ntβ-LCY 1过表达导致类胡萝卜素的大量积累和类胡萝卜素生物合成基因的表达。此外，与野生型植物相比，过表达的转基因植物表现出对盐和干旱胁迫的耐受性增强，脱落酸水平更高，丙二醛和活性氧水平更低。相反，转基因RNA干扰植物在叶片中具有明显的白化病表型，并且一些植物不能存活超过早期发育阶段。抑制Ntβ-LCY 1表达导致类胡萝卜素生物合成途径中基因的表达水平降低，类胡萝卜素、叶绿素和脱落酸的积累减少。这些结果表明，Ntβ-LCY 1不仅可能是烟草类胡萝卜素积累的环化酶，而且可能赋予烟草耐盐和干旱胁迫的能力。
Carotenoids are important pigments in plants that play crucial roles in plant growth and in plant responses to environmental stress. Lycopene β cyclase (β-LCY) functions at the branch point of the carotenoid biosynthesis pathway, catalyzing the cyclization of lycopene. Here, a β-LCY gene from Nicotiana tabacum, designated as Ntβ-LCY1, was cloned and functionally characterized. Robust expression of Ntβ-LCY1 was found in leaves, and Ntβ-LCY1 expression was obviously induced by salt, drought, and exogenous abscisic acid treatments. Strong accumulation of carotenoids and expression of carotenoid biosynthesis genes resulted from Ntβ-LCY1 overexpression. Additionally, compared to wild-type plants, transgenic plants with overexpression showed enhanced tolerance to salt and drought stress with higher abscisic acid levels and lower levels of malondialdehyde and reactive oxygen species. Conversely, transgenic RNA interference plants had a clear albino phenotype in leaves, and some plants did not survive beyond the early developmental stages. The suppression of Ntβ-LCY1 expression led to lower expression levels of genes in the carotenoid biosynthesis pathway and to reduced accumulation of carotenoids, chlorophyll, and abscisic acid. These results indicate that Ntβ-LCY1 is not only a likely cyclization enzyme involved in carotenoid accumulation but also confers salt and drought stress tolerance in Nicotiana tabacum.