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Plant Biotechnol J:利用聚胞藻鉴定类胡萝卜素代谢通路中酶的功能

已有 2206 次阅读 2019-8-31 15:33 |个人分类:每日摘要|系统分类:论文交流

Manipulation of Synechocystis sp. PCC6803 as a platform for functional identification of genes involved in carotenoid metabolism


First author: Tian‐Jun Cao; Affiliations: Nanjing University (南京大学): Nanjing, China

Corresponding author: Shan Lu


Carotenoids are not only essential light‐harvesting/photoprotective pigments for plants, but also essential phytonutrients for human health. Although the carotenoid metabolic pathway is generally shared by photosynthetic organisms, some unique carotenoids are only synthesized in particular species. Eludication of the enzymes that catalyze their biosynthesis is a prerequisite for manipulating their production by transgenic and synthetic biological approaches. Both pigment complementation in Escherichia coli and gene overexpression in the wild‐type and corresponding silencing mutants of Arabidopsis thaliana have been used for functional characterization of putative enzymes but with some limits. In this study, we engineered the carotenoid metabolic pathway of the cyanobacterium Synechocystis sp. PCC6803 by silencing its endogenous carotene hydroxylase gene (CrtO) and introducing different exogenous genes. With the zeaxanthin epoxidase gene from A. thaliana, we extended the metabolic pathway from zeaxanthin to violaxanthin in Synechocystis. We also established in Synechocystis the metabolic branch from lycopene to lutein, which does not naturally exist in cyanobacteria and some algal phyla, by transforming with the genes for lycopene ε‐cyclase (Lut2) and carotene ε‐hydroxylase (Lut1) from A. thaliana. Our results also confirmed that the endogenous carotene β‐hydroxylase CrtR could only hydroxylate the unsubstituted β‐ring. Taken together, we demonstrated that Synechocystis can be manipulated as a new platform for the functional characterization of unknown proteins that have putative functions on carotenoid metabolism.




类胡萝卜素不仅作为植物的光捕获和光保护色素发挥重要作用,同时也是人类健康需要的植物营养素。尽管类胡萝卜素代谢通路在光合生物中普遍存在,但有一些特定的类胡萝卜素只在特定的物种中产生。理解催化这些类胡萝卜素生物合成的酶的功能是我们应用转基因或合成生物学方法生产这些类胡萝卜素的前提条件。研究人员通常利用大肠杆菌中的色素互补试验以及拟南芥中的基因过表达或基因沉默试验来鉴定某些酶的功能,但仍存在局限性。本文中,作者在蓝藻模式生物聚胞藻PCC6803中沉默其本身的胡萝卜素羟化酶基因CrtO,并引入不同的外源基因,构建了新的类胡萝卜素代谢通路。通过引入拟南芥中的玉米黄质环氧化酶基因,作者在聚胞藻中将玉米黄质成功合成为紫黄质,人为拓展了聚胞藻中类胡萝卜素代谢通路。另外,作者还在聚胞藻中建立了原本蓝藻和一些藻类物种中本不存在的类胡萝卜素代谢分枝,比如通过引入拟南芥中的番茄红素ε-环化酶Lut2和胡萝卜素ε-羟化酶Lut1,作者成功在聚胞藻中建立了从番茄红素到叶黄素的代谢路径。本文的结果确认了内源的胡萝卜素β-羟化酶CrtR仅能使未被取代的β-环羟基化。综上,本文的研究揭示了聚胞藻可以作为一个新的平台,应用于对某些可能参与类胡萝卜素代谢但未知其具体作用的蛋白进行功能鉴定。



通讯卢山https://life.nju.edu.cn/ls_14014/list.htm)


研究方向:1. 萜类合成酶功能域结构与产物立体异构方式的关系;2. 植物对挥发性萜类信号的识别;3. 光信号对植物类胡萝卜素合成与积累的调控。



doi: https://doi.org/10.1111/pbi.13245


Journal: Plant Biotechnology Journal

Published date: August 30, 2019


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https://blog.sciencenet.cn/blog-3158122-1196040.html

上一篇:Nature Plants:组织特异性积累的脂质磷脂酸作用于植物的盐胁迫抗性
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