转录因子调控植物萜类化合物生物合成研究进展

萜类化合物是植物次生代谢物中结构和数量最多的一类化合物, 它们在植物体内以及植物与环境和其它生命体的相互作用中发挥重要作用。转录因子通过调控代谢通路中基因的转录起始来调节次生代谢物质的产量。目前, 研究发现参与萜类合成的转录因子家族主要有6个, 包括AP2/ERF、bHLH、MYB、NAC、WRKY和bZIP。该文主要对其家族的结构特点、调控模式以及研究进展进行综述, 以期进一步丰富萜烯合成的网络调控, 为植物萜类相关的分子育种、优质栽培和病虫害生物防治等提供新的思路与方法。     

Production and engineering of terpenoids in plant cell culture

Terpenoids are a diverse class of natural products that have many functions in the plant kingdom and in human health and nutrition. Their chemical diversity has led to the discovery of over 40,000 different structures, with several classes serving as important pharmaceutical agents, including the anticancer agents paclitaxel (Taxol) and terpenoid-derived indole alkaloids. Many terpenoid compounds are found in low yield from natural sources, so plant cell cultures have been investigated as an alternate production strategy. Metabolic engineering of whole plants and plant cell cultures is an effective tool to both increase terpenoid yield and alter terpenoid distribution for desired properties such as enhanced flavor, fragrance or color. Recent advances in defining terpenoid metabolic pathways, particularly in secondary metabolism, enhanced knowledge concerning regulation of terpenoid accumulation, and application of emerging plant systems biology approaches, have enabled metabolic engineering of terpenoid production. This paper reviews the current state of knowledge of terpenoid metabolism, with a special focus on production of important pharmaceutically active secondary metabolic terpenoids in plant cell cultures. Strategies for defining pathways and uncovering rate-influencing steps in global metabolism, and applying this information for successful terpenoid metabolic engineering, are emphasized.     

基于整合方法分析茶树响应病原真菌胁迫的共有模式

为探讨茶树(Camellia sinensis)对病菌胁迫的共有响应模式和抗病机制,运用生物信息学方法对多组RNA-seq数据进行提取、整合及功能富集,结合多种工具和数据库资源对主要调控分子及蛋白互作模块加以分析。结果表明,病原真菌胁迫下,茶树有较多细胞色素P450家族成员表达显著上调;类固醇和激素的代谢过程、苯丙烷合成途径被激活,有丝分裂细胞周期调控、DNA甲基化等生物过程及光合作用途径受到抑制;主要调控分子如转录因子WRKY和NAC、激酶RLK-Pelle和CAMK等以上调为主。差异表达的蛋白互作模块分析表明,有丝分裂周期调控、基于微管运动、淀粉和蔗糖代谢、细胞壁多糖合成、光合作用、类黄酮代谢模块明显下调,木质素合成和萜类生物合成模块上调;且模块之间可能存在互作。病菌胁迫激活的木质素和萜类合成途径的关键基因包括阿魏酸-5-羟基化酶基因F5H、过氧化物酶基因POD和萜类合成酶基因HMGR等。细胞色素P450基因可能在病菌胁迫中起关键作用,增强木质素和萜类物质的合成、削弱光合作用可能是茶树响应真菌胁迫的核心模式。     

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.     

季节变化对聚果榕-榕小蜂互利共生系统生长与繁殖的影响

榕属植物及其传粉昆虫榕小蜂是自然界协同进化的经典模型,榕果内雌花资源如何分配一直是备受关注的问题。为验证季节变化对榕树-榕小蜂互利共生系统生长与繁殖的影响,该研究以西双版纳地区的聚果榕(Ficus racemosa)为材料,分析了季节变化对榕果大小、自然进蜂量以及榕树-榕小蜂繁殖的影响,并利用人工控制性放蜂实验和模型拟合,探讨榕果最适进蜂量及不同季节进蜂量对雌花资源分配的影响。结果表明:季节对榕果直径有显著影响,雨季的榕果直径显著小于干热季和雾凉季;不同季节的自然进蜂量也有显著差别,苞片口对调节进蜂数量有重要作用;季节对榕树-榕小蜂繁殖分配也有影响,雾凉季产生的种子数量和榕小蜂数量均最多;同时人工控制实验和二次抛物线模型拟合结果表明,母代雌蜂数量与种子及榕小蜂后代数量均呈抛物线关系,雌蜂数量过多或过少都对榕树-榕小蜂的繁殖不利,自然进蜂量与拟合的最优进蜂量基本一致。研究结果说明榕果进化出了适应西双版纳地区季节变化的繁殖策略。     

Plant Terpenoids： Biosynthesis and Ecological Functions

Among plant secondary metabolites terpenolds are a structurally most diverse group; they function as phytoalexins In plant direct defense, or as signals In Indirect defense responses which involves herbivores and their natural enemies. In recent years, more and more attention has been paid to the Investigation of the ecological role of plant terpenolds. The biosynthesis pathways of monoterpenes, sesquiterpenes, and diterpenes Include the synthesis of C5 precursor isopentenyl diphosphate （IPP） and Its allylic isomer dlmethylallyl dlphosphate （DMAPP）, the synthesis of the immediate diphosphate precursors, and the formation of the diverse terpenoids. Terpene synthases （TPSs） play a key role In volatile terpene synthesis. By expression of the TPS genes, significant achievements have been made on metabolic engineering to Increase terpenoid production. This review mainly summarizes the recent research progress In elucidating the ecological role of terpenoids and characterization of the enzymes Involved in the terpenold biosynthesis. Spatial and temporal regulations of terpenoids metabolism are also discussed.     

Volatile science? Metabolic engineering of terpenoids in plants

Terpenoids are important for plant survival and also possess biological properties that are beneficial to humans. Here, we describe the state of the art in terpenoid metabolic engineering, showing that significant progress has been made over the past few years. Subcellular targeting of enzymes has demonstrated that terpenoid precursors in subcellular compartments are not as strictly separated as previously thought and that multistep pathway engineering is feasible, even across cell compartments. These engineered plants show that insect behavior is influenced by terpenoids. In the future, we expect rapid progress in the engineering of terpenoid production in plants. In addition to commercial applications, such transgenic plants should increase our understanding of the biological relevance of these volatile secondary metabolites.     

Perspectives and limits of engineering the isoprenoid metabolism in heterologous hosts

Terpenoids belong to the largest class of natural compounds and are produced in all living organisms. The isoprenoid skeleton is based on assembling of C5 building blocks, but the biosynthesis of a great variety of terpenoids ranging from monoterpenoids to polyterpenoids is not fully understood today. Terpenoids play a fundamental role in human nutrition, cosmetics, and medicine. In the past 10 years, many metabolic engineering efforts have been undertaken in plants but also in microorganisms to improve the production of various terpenoids like artemisinin and paclitaxel. Recently, inverse metabolic engineering and combinatorial biosynthesis as main strategies in synthetic biology have been applied to produce high-cost natural products like artemisinin and paclitaxel in heterologous microorganisms. This review describes the recent progresses made in metabolic engineering of the terpenoid pathway with particular focus on fundamental aspects of host selection, vector design, and system biotechnology.     

bZIP转录因子调控植物次生代谢产物生物合成的研究进展

植物次生代谢产物是通过次生代谢产生的一类小分子有机化合物,是植物适应环境的表现,次生代谢产物也是重要药物和化工原料的来源。bZIP转录因子是普遍存在于真核生物中的一类多基因家族,可有效调控植物次生代谢产物的生物合成。本文概述了植物bZIP转录因子的结构和类型,重点阐述了bZIP转录因子调控萜类、黄酮类和生物碱等植物次生代谢产物生物合成的研究进展,并对研究前景进行了展望。深入探讨bZIP转录因子的调控机制,有助于利用基因工程技术优化植物次生代谢途径,提高次生代谢产物的含量,在新药创制、工农业生产等方面具有广泛的应用前景。     

利用类萜代谢工程改良作物风味

类萜是从植物中分离出的一类类异戊二烯物质。其中挥发性萜类除了在吸引授粉媒、异株克生和植物防御中起到一定的生态作用外,还影响到水果、蔬菜和其他作物的香味形成。对类萜生物合成及其代谢工程的最新研究进展进行了综述,探讨了代谢过程中的关键酶基因,尤其是类萜合成酶(TPSs)基因的表达特性以及操纵类萜生物合成途径提高产量的几种可能的策略。随着更多相关基因的分离,利用代谢工程人工改良作物风味将指日可待。     

植物苯丙烷代谢途径

众所周知,固着生长的植物经常受到环境中各种生物和非生物胁迫的威胁。所以在漫长的进化过程中,植物必须将多样的环境信号整合到其发育过程中,以实现适应性形态的发生和代谢途径的精确调控,最终使植物完成整个生长周期。研究显示,苯丙烷代谢作为植物重要的次级代谢途径之一,其代谢产物,例如木质素、孢粉素、花青素和有机酸等,在调控植物适应性生长的过程中发挥着重要功能。特别是在药用植物中,苯丙烷代谢还与众多药用活性成分的合成息息相关,几乎所有包含苯丙烷骨架的天然药效成分均由苯丙烷代谢途径直接或间接合成,例如黄酮类、萜类和酚类等。此外,经苯丙烷代谢途径产生的一些次级代谢产物还能由植物根系外泌到周际土壤中,通过改变根系微生物的菌群生态,而影响植物生长和抵抗生物或非生物胁迫的能力。同时,苯丙烷代谢介导的这种植物-微生物互作也与药用植物的道地品质密不可分。本文综述了近年来植物苯丙烷代谢途径的最新研究进展,重点对该代谢途径中代谢产物的生理功能及表达调控机制进行了介绍,以期更深入地理解药用植物苯丙烷代谢与药材性状之间的潜在关系,旨在指导优良中草药的遗传育种,以进一步促进我国中医药事业的蓬勃发展。     

植物萜类代谢工程

植物萜类化合物不仅在植物生命活动中起重要作用,而且具有重要商业价值。随着近年来萜类代谢途径和调控机理研究的深入,代谢工程已成为提高萜类产量最有潜力的途径之一。对萜类代谢工程领域具代表性的研究结果进行了全面回顾,然后讨论了萜类代谢工程的研究方法和策略,其中重点探讨了功能基因组学方法在萜类代谢途径及调控机理研究方面的应用。