植物次生代谢基因工程

植物次生代谢基因工程,是利用基因工程技术对植物次生代谢途径的遗传特性进行改造,进而改变植物次生代谢产物。植物次生代谢基因工程的出现是人类对次生代谢途径的深入了解和分子生物学向纵深发展的结果,同时它又促进了次生代谢分子生物学的发展。调控因子的应用和多基因的协同转化为植物次生代谢基因工程拓宽了思路。从次生代谢图谱、植物基因工程策略和植物转基因方法等方面对植物次生代谢的基因工程研究进展做一简要概述。     

植物细胞培养生产次生代谢物的途径

利用植物细胞培养生产次生代谢产物是一种快速、高效获取天然产物的重要方法。本文从培养方法、培养技术、生物转化及基因工程应用三个方面,综述了近年来国内外应用于植物细胞培养生产次生代谢产物的途径及研究进展,论述了次生代谢产物的主要类型及合成途径,列举了应用实例和次生代谢物种类以及相应的培养条件,以期对快速选择提高目的次生代谢物的培养条件起到了一定指导作用。     

参与植物次生代谢调控的转录因子及其在植物次生代谢遗传改良中的应用

转录因子与结构基因的结合,激活合成基因的表达是次生代谢物合成途径启动前的重要分子事件,对植物次生代谢起着十分重要的调节作用。转录因了可激活次牛代谢物合成途径中多个基因协同表达,从而有效启动次生代谢途径。因此,转录因子为揭示植物次生代谢调控机制提供重要工具,转录因子的基因工程可为植物次生代谢的遗传改良提供有效的手段。     

丹参代谢途径关键酶和次生代谢产物的研究进展

丹参次生代谢物是丹参入药的主要成分，文章从丹参次生代谢物的主要类型、合成途径、关键酶及培养环境的变化对丹参次生代谢物的影响等方面，综述了近年来国内外对丹参次生代谢产物积累的研究进展，论述了植物次生代谢主要合成途径中关键酶与代谢物积累的相关作用，列举了环境变化、诱导作用对丹参次生代谢物含量变化的影响，旨在为丹参的规范化种植和质量控制提供理论依据。     

植物次生代谢基因工程研究进展

随着对植物代谢网络日渐全面的认识,应用基因工程技术对植物次生代谢途径进行遗传改良已取得了可喜的进展.对次生代谢途径进行基因修饰的策略包括:导入单个、多个靶基因或一个完整的代谢途径,使宿主植物合成新的目标物质;通过反义RNA和RNA干涉等技术降低靶基因的表达水平,从而抑制竞争性代谢途径,改变代谢流和增加目标物质的含量;对控制多个生物合成基因的转录因子进行修饰,更有效地调控植物次生代谢以提高特定化合物的积累.作者结合对大豆种子异黄酮类代谢调控和基因工程改良的研究,着重介绍了花青素和黄酮类物质、生物碱、萜类化合物和安息香酸衍生物等次生代谢产物生物合成的基因工程研究进展.     

植物次生代谢物的应用和开发

植物次生代谢是植物对环境的一种适应,植物次生代谢物为人类提供了丰富的药用、食用等资源。近年来,植物次生代谢物成为研究热点,就其应用价值和开发途径作了简要概述。     

几种重要植物次生代谢防御反应物质的生物合成途径及分子调控机制研究进展

参与植物防御反应相关的次生代谢产物主要有酚类、萜类和生物碱类.近几年,随着转录组学、蛋白组学及新的分子生物学技术的广泛应用,极大地推进了植物次生代谢防御反应物质调控机制的研究进展.我们从这几类次生代谢物质的合成途径及其参与植物防御反应的分子调控机制两大方面进行概述,重点介绍这三类具有防御作用的次生代谢产物的生物合成途径、参与介导植物防御反应的相关信号分子及其转录调控机制,为正确认识植物次生代谢防御反应提供理论据.     

植物次生代谢的分子生物学及基因工程

植物次生代谢是植物对环境的一种应用,是植物主要的防卸机制之一。植物次生代谢物为人类提供了丰富的药物、香料等资源。近年来植物次生代谢途径关键酶的基因克隆和分子调控的研究成为热点。黄酮类生物合成分子生物学研究最为深入。在异戊二烯途径中,萜类合成酶已从４种植物中克隆,包括单萜,倍半萜和二萜合成酶,这些将对农业与医药产生重要影响。     

虫害诱导植物合成防御性次生代谢产物的研究进展

昆虫对植物的取食活动可以激活植物的防御反应,诱导植物通过调控自身的代谢网络合成防御性次生代谢产物,抵御外界不良刺激。虫害诱导植物合成防御性次生代谢产物及其机制研究已成为近年来的研究热点之一。现对虫害诱导的植物防御性次生代谢产物、昆虫危害产生的各类激发子、植物对激发子的识别、虫害应答相关的信号转导通路及其对次生代谢物质积累的调控进行了综述,可为虫害诱导植物合成防御性次生代谢产物的机制研究提供参考,为植物虫害防治研究、植物次生代谢物质的生产和利用提供理论依据。     

高等植物中维生素C 的功能、合成及代谢研究进展

植物体内合成的维生素C在植物抗氧化和自由基清除、光合作用和光保护、细胞生长和分裂以及一些重要次生代谢物和乙烯的合成等方面具有非常重要的生理功能。维生素C的生物合成途径及其代谢调控的基因工程研究最近取得了突破。     

Making new molecules - evolution of pathways for novel metabolites in plants

Plants have adapted to their environments by diversifying in various ways. This diversification is reflected at the phytochemical level in their production of numerous specialized secondary metabolites that provide protection against biotic and abiotic stresses. Plant speciation is therefore intimately linked to metabolic diversification, yet we do not currently have a deep understanding of how new metabolic pathways evolve. Recent evidence indicates that genes for individual secondary metabolic pathways can be either distributed throughout the genome or clustered, but the relative frequencies of these two pathway organizations remain to be established. While it is possible that clustering is a feature of pathways that have evolved in recent evolutionary time, the answer to this and how dispersed and clustered pathways may be related remain to be addressed. Recent advances enabled by genomics and systems biology are beginning to yield the first insights into network evolution in plant metabolism. This review focuses on recent progress in understanding the evolution of clustered and dispersed pathways for new secondary metabolites in plants.     

Lessons learned from metabolic engineering of cyanogenic glucosides

Plants produce a plethora of secondary metabolites which constitute a wealth of potential pharmaceuticals, pro-vitamins, flavours, fragrances, colorants and toxins as well as a source of natural pesticides. Many of these valuable compounds are only synthesized in exotic plant species or in concentrations too low to facilitate commercialization. In some cases their presence constitutes a health hazard and renders the crops unsuitable for consumption. Metabolic engineering is a powerful tool to alter and ameliorate the secondary metabolite composition of crop plants and gain new desired traits. The interplay of a multitude of biosynthetic pathways and the possibility of metabolic cross-talk combined with an incomplete understanding of the regulation of these pathways, explain why metabolic engineering of plant secondary metabolism is still in its infancy and subject to much trial and error. Cyanogenic glucosides are ancient defense compounds that release toxic HCN upon tissue disruption caused e.g. by chewing insects. The committed steps of the cyanogenic glucoside biosynthetic pathway are encoded by three genes. This unique genetic simplicity and the availability of the corresponding cDNAs have given cyanogenic glucosides pioneering status in metabolic engineering of plant secondary metabolism. In this review, lessons learned from metabolic engineering of cyanogenic glucosides in Arabidopsis thaliana (thale cress), Nicotiana tabacum cv Xanthi (tobacco), Manihot esculenta Crantz (cassava) and Lotus japonicus (bird’s foot trefoil) are presented. The importance of metabolic channelling of toxic intermediates as mediated by metabolon formation in avoiding unintended metabolic cross-talk and unwanted pleiotropic effects is emphasized. Likewise, the potential of metabolic engineering of plant secondary metabolism as a tool to elucidate, for example, the impact of secondary metabolites on plant–insect interactions is demonstrated.     

The effects of season and water availability on chemical composition,secondary metabolites and biological activity in plants

Plants react towards changes in their environment, which can be a result of biotic or abiotic activities. Numerous studies have investigated the effects of abiotic stress on plants, and how it affects the primary as well as secondary metabolism. Generally it is accepted that plants react to environmental stress by increasing secondary metabolites. This is however a very broad and simplified explanation and often inaccurate. Various examples are provided where plants react positively, and often negatively towards seasonal variation and water availability, resulting in a lowering of certain secondary metabolites concentration, while others are increased. Furthermore species differences, cultivars and interaction of other environmental factors such as temperature complicates a simple conclusion from the effect of stress on plants. The differential expression of genes in different species and in different metabolic pathways ensures a complex and very specific reaction of a plant to environmental stress. Overall the paper provides support for a complex and intricate response system which differs for each plant species, and could be explained by understanding and studying the different metabolic pathways responsible for secondary metabolite production.     

昆虫对植物次生物质的代谢适应机制及其对昆虫抗药性的意义

植物次生物质(plant secondary metabolites)对昆虫的取食行为、生长发育及繁殖可以产生不利影响,甚至对昆虫可以产生毒杀作用。为了应对植物次生物质的不利影响,昆虫通过对植物次生物质忌避取食、解毒代谢等多种机制,而对寄主植物产生适应性。其中,昆虫的解毒代谢酶包括昆虫细胞色素P450酶系（P450s）及谷胱甘肽硫转移酶（GSTs）等,在昆虫对植物次生物质的解毒代谢及对寄主植物的适应性中发挥了重要作用。昆虫的解毒酶系统不仅可以代谢植物次生物质,还可能代谢化学杀虫剂,因而昆虫对寄主植物的适应性与其对杀虫剂的耐药性甚至抗药性密切相关。昆虫细胞色素P450s和GSTs等代谢解毒酶活性及相关基因的表达可以被植物次生物质影响,这不仅使昆虫对寄主植物的防御产生了适应性,还影响了昆虫对杀虫剂的解毒代谢,因而改变昆虫的耐药性或抗药性。掌握昆虫对植物次生物质的代谢适应机制及其在昆虫抗药性中的作用,对于明确昆虫的抗药性机制具有重要的参考意义。本文综述了植物次生物质对昆虫的影响、昆虫对寄主植物次生物质的代谢机制、昆虫对植物次生物质的代谢适应性对昆虫耐药性及抗药性的影响等方面的研究进展。     

Engineering secondary metabolite production in plants

Recent achievements have been made in the metabolic engineering of plant secondary metabolism. Various pathways have been altered using genes encoding biosynthetic enzymes or genes encoding regulatory proteins. In addition, antisense genes have been used to block competitive pathways, thereby increasing the flux towards the desired secondary metabolites.