title: Cloning of the Lycopene β-cyclase Gene in Nicotiana tabacum and Its Overexpression Confers Salt and Drought Tolerance.
abstract: 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.
authors.affiliation: College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001, Henan, China. symzgh@163.com.|National Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute, Zhengzhou 450001, Henan, China. symzgh@163.com.
authors.forename: Yanmei
authors.initials: Y
authors.lastname: Shi
authors.affiliation: Institute of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng 475004, Henan, China. jgguo@henu.edu.cn.
authors.forename: Jinggong
authors.initials: J
authors.lastname: Guo
authors.affiliation: China National Tobacco Quality Supervision &amp; Test Centre, Zhengzhou 450001, Henan, China. zhangw_jh@163.com.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.affiliation: National Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute, Zhengzhou 450001, Henan, China. jin_lf@126.com.
authors.forename: Lifeng
authors.initials: L
authors.lastname: Jin
authors.affiliation: National Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute, Zhengzhou 450001, Henan, China. Liu_pingping2012@163.com.
authors.forename: Pingping
authors.initials: P
authors.lastname: Liu
authors.affiliation: National Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute, Zhengzhou 450001, Henan, China. chenxia0372@163.com.
authors.forename: Xia
authors.initials: X
authors.lastname: Chen
authors.affiliation: National Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute, Zhengzhou 450001, Henan, China. likite2002@163.com.
authors.forename: Feng
authors.initials: F
authors.lastname: Li
authors.affiliation: National Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute, Zhengzhou 450001, Henan, China. weipan83@126.com.
authors.forename: Pan
authors.initials: P
authors.lastname: Wei
authors.affiliation: National Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute, Zhengzhou 450001, Henan, China. ibi.zefeng@gmail.com.
authors.forename: Zefeng
authors.initials: Z
authors.lastname: Li
authors.affiliation: Yunnan Academy of Tobacco Agricultural Sciences, Kunming 650031, Yunnan, China. lwz67@163.com.
authors.forename: Wenzheng
authors.initials: W
authors.lastname: Li
authors.affiliation: Staff Training Academy of CNTC, Zhengzhou 450008, Henan, China. ztrisam@126.com.
authors.forename: Chunyang
authors.initials: C
authors.lastname: Wei
authors.affiliation: National Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute, Zhengzhou 450001, Henan, China. zhengqingxia916@126.com.
authors.forename: Qingxia
authors.initials: Q
authors.lastname: Zheng
authors.affiliation: National Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute, Zhengzhou 450001, Henan, China. chen_qiansi@163.com.
authors.forename: Qiansi
authors.initials: Q
authors.lastname: Chen
authors.affiliation: National Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute, Zhengzhou 450001, Henan, China. Jianfengzhang068@gmail.com.
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Zhang
authors.affiliation: National Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute, Zhengzhou 450001, Henan, China. fuchenglin@zju.edu.cn.
authors.forename: Fucheng
authors.initials: F
authors.lastname: Lin
authors.affiliation: College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001, Henan, China. qulingbo@zzu.edu.cn.
authors.forename: Lingbo
authors.initials: L
authors.lastname: Qu
authors.affiliation: National Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute, Zhengzhou 450001, Henan, China. johnhughsnyder@gmail.com.
authors.forename: John Hugh
authors.initials: JH
authors.lastname: Snyder
authors.affiliation: National Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute, Zhengzhou 450001, Henan, China. wangranljj2010@163.com.
authors.forename: Ran
authors.initials: R
authors.lastname: Wang
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D000595:Amino Acid Sequence; D055864:Droughts; D019753:Intramolecular Lyases / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D055049:Salt Tolerance / Q000235:genetics*; D013312:Stress, Physiological; D014026:Nicotiana / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D017382:Reactive Oxygen Species; D000040:Abscisic Acid; D019753:Intramolecular Lyases; C070925:lycopene cyclase-isomerase
keywords: Nicotiana tabacum; abscisic acid; carotenoid biosynthesis; lycopene β-cyclase; reactive oxygen species; salt and drought tolerance