环境因子调控植物花青素苷合成及呈色的机理

花青素苷（anthocyanin）是决定被子植物花、果实和种皮等颜色的重要色素之一。花青素苷的合成与积累过程往往与植物发育过程密切相关,由内外因子共同控制。环境因子通过诱导植物体内花青素苷合成途径相关基因的表达来调控花青素苷的呈色反应。该文追踪了国内外相关研究,认为光是影响花青素苷呈色的主要环境因子之一,光质和光强均能在一定程度上影响花青素苷的合成,其中光质起着更为关键的作用;低温能诱导花青素苷的积累,高温则会加速花青素苷的降解;不同的糖类物质均能影响花青素苷的合成,大部分结构基因和调节基因的表达均受糖调控。关于花发育与花青素苷呈色的关系、观赏植物花色对环境因子的响应以及花青素苷抵御逆境的机理尚待深入研究。因此,综合考察花发育与植物花青素苷合成及其呈色之间的关系,特别是光周期对花发育的影响导致花青素苷合成及呈色的机理是花色研究的一个重要课题。利用环境因子调控花色将会极大地提高花卉的观赏价值。     

环境因子调控植物花青素苷合成及呈色的机理

花青素苷(anthocyanin)是决定被子植物花、果实和种皮等颜色的重要色素之一。花青素苷的合成与积累过程往往与植物发育过程密切相关, 由内外因子共同控制。环境因子通过诱导植物体内花青素苷合成途径相关基因的表达来调控花青素苷的呈色反应。该文追踪了国内外相关研究, 认为光是影响花青素苷呈色的主要环境因子之一, 光质和光强均能在一定程度上影响花青素苷的合成, 其中光质起着更为关键的作用; 低温能诱导花青素苷的积累, 高温则会加速花青素苷的降解;不同的糖类物质均能影响花青素苷的合成, 大部分结构基因和调节基因的表达均受糖调控。关于花发育与花青素苷呈色的关系、观赏植物花色对环境因子的响应以及花青素苷抵御逆境的机理尚待深入研究。因此, 综合考察花发育与植物花青素苷合成及其呈色之间的关系, 特别是光周期对花发育的影响导致花青素苷合成及呈色的机理是花色研究的一个重要课题。利用环境因子调控花色将会极大地提高花卉的观赏价值。     

植物花瓣呈色机理及花色分子育种

植物花瓣呈色的主要化学物质包括类黄酮/花青素苷、类胡萝卜素和甜菜色素。其中类黄酮/花青素苷是分布最广泛的色素,决定大多数植物花瓣的呈色;类胡萝卜素在一些植物黄色至橙红色花瓣中起着作用;而甜菜色素主要存在于石竹目植物,包含甜菜红素和甜菜黄素。目前,关于色素生物合成的分子网络已被解析,主要由一系列结构基因控制;一些与色素合成相关的调控因子在很多植物中被鉴定发现。另外,基于外源基因表达或内源基因编辑的分子育种在一些观赏植物的花色改良中被成功应用。本文系统性总结了植物中3种类型色素合成的分子基础、调控机制及分子育种应用等方面的研究进展;将有助于提高我们对植物色素合成分子调控网络的认识,并以期为今后开展花色分子设计育种提供理论支持。     

低温对牡丹切花花色和花青素苷合成的影响

以牡丹洛阳红(Paeonia suffruticosa‘Luoyang Hong’)开放级别为蕾开期的切花为材料,研究不同温度(22℃、15℃和4℃)处理对切花花色和花青素苷合成的影响。结果表明:与22℃处理相比,15℃和4℃处理切花花色明度下降、红度和彩度增加,花瓣花青素苷含量增加。对花青素苷合成相关基因表达量分析的结果表明:15℃和4℃低温促进与花青素苷合成相关的PsCHS1、PsCHI1、PsF3'H1、PsANS1、PsDFR1、PsMYB2、Psb HLH1和Psb HLH3基因的表达。低温对花青素苷上游合成途径中PsCHS1和PsCHI1基因进行调控;下游合成途径中PsDFR1、PsANS1和PsF3'H1基因对低温的响应相对敏感,4℃处理后基因的表达量大幅上调,且显著高于15℃处理组。上述所提到的结构基因和调节基因均是受低温调控的关键基因,进而影响牡丹洛阳红切花花青素苷合成与积累。     

葡萄花青素苷生物合成研究进展

花青素苷是一类重要的天然色素物质,是植物主要呈色物质之一,并在人类健康保护方面发挥越来越重要的作用。同时,它又是一类复杂性状,不仅与遗传基因相关,还与外界温度、湿度、光质及栽培措施等因素息息相关。葡萄花青素苷是近年来花青素苷研究的热点,主要从葡萄花青素苷的结构多样性和合成途径等方面展开简要综述,以期为葡萄花青素苷复杂性状的遗传机理和调控作用机制与分子育种及葡萄优质早熟栽培研究上提供有益的信息。     

三色(Bougainvillea peruviana‘Thimma’)在转录水平的甜菜色素和类黄酮积累比较

Bougainvillea peruviana‘Thimma’属于三角梅属,该属植物积累甜菜色素而不是像绝大多数高等植物一样积累花青素。该材料特征同株出现3种颜色：白色、洋红色和白/洋红相间。本研究首次使用3种花色特征的花序（红色Yp、混合色的Ym、白色Yw）作为研究材料进行高通量测序。并通过real-time PCR方法对探测到的花色代谢基因进行验证。共获得平均长度为616 bp的73 325条基因。3种材料的差异显示基因（DEGs）中有327个被注释到甜菜色素合成基因,308个被注释到类黄酮合成基因,466个被注释到花青素合成基因。我们选出8个基因：4个甜菜色素合成基因（PPO,CYP76AD1,cDOPA-5-GT,DODA）和4个花青素合成基因（FLS,DFR,LDOX,3-GT）进行验证。其中,4个甜菜色素合成基因在3种花色材料中的表达较好的正相关于甜菜色素含量。花青素合成途径末端的3个基因（DFR,LDOX,3-GT）在B.peruviana中首次被验证。real-time PCR的验证结果很好的吻合转录组测序的结果。同时,B.peruviana也提供了一个很好的三角梅属植物的生理、生化和分子生物学研究的工具,有效的摒除其他生物学干扰。     

三色(Bougainvillea peruviana ‘Thimma’)在转录水平的甜菜色素和类黄酮积累比较（英文）

Bougainvillea peruviana‘Thimma’属于三角梅属,该属植物积累甜菜色素而不是像绝大多数高等植物一样积累花青素。该材料特征同株出现3种颜色:白色、洋红色和白/洋红相间。本研究首次使用3种花色特征的花序(红色Yp、混合色的Ym、白色Yw)作为研究材料进行高通量测序。并通过real-time PCR方法对探测到的花色代谢基因进行验证。共获得平均长度为616 bp的73 325条基因。3种材料的差异显示基因(DEGs)中有327个被注释到甜菜色素合成基因,308个被注释到类黄酮合成基因,466个被注释到花青素合成基因。我们选出8个基因:4个甜菜色素合成基因(PPO,CYP76AD1,c DOPA-5-GT,DODA)和4个花青素合成基因(FLS,DFR,LDOX,3-GT)进行验证。其中,4个甜菜色素合成基因在3种花色材料中的表达较好的正相关于甜菜色素含量。花青素合成途径末端的3个基因(DFR,LDOX,3-GT)在B.peruviana中首次被验证。real-time PCR的验证结果很好的吻合转录组测序的结果。同时,B.peruviana也提供了一个很好的三角梅属植物的生理、生化和分子生物学研究的工具,有效的摒除其他生物学干扰。     

可视安全标记花青素合成途径相关基因在植物转化研究中的应用进展

近年来有关转基因产品可能带来的环境和食品安全问题的争论多集中在作为标记基因的抗生素抗性基因以及抗除草剂基因的广泛使用。因此寻找安全、有效的标记基因替代上述有争议标记基因就显得十分必要和紧迫。花青素合成酶类及其合成调控因子可以控制植物体内的色素合成,一些转化研究已证明其转化体表型发生了颜色改变。加之花青素类物质是一些天然色素,对人类有利而无害,可以利用花青素的这些特点,将花青素合成酶类及其调控因子基因作为一类可视化、安全和有效的标记基因来转化植物。本文就可视安全标记花青素合成酶类基因及其调控基因在植物转化研究中的应用进展进行了简要介绍,以期为提高标记基因的安全性提供参考。     

冬性植物红菜薹在不同温度处理下花青素积累的分子机制

芸薹属植物红菜薹（Brassica rapa）是一种常见的蔬菜,它的花茎和叶柄表皮中均积累有花青素。为了解红菜薹中花青素合成的分子机制,进行了花青素含量的测定和花青素合成相关基因的表达分析。研究结果表明,叶柄表皮中的花青素含量显著高于叶片（去主脉）的花青素含量。同时,叶柄表皮花青素合成相关基因的表达水平高于叶柄（去表皮）和叶片（去主脉）的表达水平,这表明红菜薹中花青素的合成调控发生在转录水平。BrMYBA1仅在叶柄表皮中表达,但BrbHLH1和BrWD40在叶片和叶柄表皮中均能检测到表达。因此,BrMYBA1的转录激活可能与红菜薹的花青素合成相关。连续低温处理时,红菜薹叶柄表皮中的花青素含量逐渐增加,而该组织中花青素合成的结构基因表达水平逐渐降低。     

花青素合成途径中分子调控机制的研究进展

花青素是广泛存在于植物中的天然水溶性色素。植物不同物种中花青素生物合成代谢途径的遗传特性和调控机制决定了该物种的花色。目前花青素生物合成途径的研究已清晰透彻。花青素合成途径的调控主要发生在结构基因的转录水平上,受多种转录因子的调控。研究发现,对花青素代谢途径中结构基因起调控作用的重要转录因子,主要包括WD40重复蛋白、b HLH蛋白和R2R3-MYB蛋白,这些转录因子之间的结合及其相互作用决定结构基因的表达。本文着重介绍花青素生物合成途径的分子调控机制,即转录因子通过形成三聚体复合物,与结构基因的启动子结合来调控结构基因的表达,并概述其在花色改造基因工程及定向改变花青素含量中的应用。     

Analysis and biological activities of anthocyanins

Anthocyanins are naturally occurring compounds that impart color to fruits, vegetables, and plants. They are probably the most important group of visible plant pigments besides chlorophyll. Apart from imparting color to plants, anthocyanins also have an array of health-promoting benefits, as they can protect against a variety of oxidants through a various number of mechanisms. However, anthocyanins have received less attention than other flavonoids, despite this. This article reviews their biological functions and pre-clinical studies, as well as the most recent analytical techniques concerning anthocyanin isolation and identification.     

Linkage of the <Emphasis Type="Italic">A</Emphasis> locus for the presence of anthocyanin and <Emphasis Type="Italic">fs10.1</Emphasis>, a major fruit-shape QTL in pepper

The purple color of the foliage, flower and immature fruit of pepper ( Capsicum spp.) is a result of the accumulation of anthocyanin pigments in these tissues. The expression of anthocyanins is controlled by the incompletely dominant gene A. We have mapped A to pepper chromosome 10 in a Capsicum annuum (5226) x Capsicum chinense (PI 159234) F(2) population to a genomic region that also controls anthocyanin expression in two other Solanaceous species, tomato and potato, suggesting that variation for tissue-specific expression of anthocyanin pigments in these plants is controlled by an orthologous gene(s). We mapped an additional locus, Fc, for the purple anther filament in an F(2) population from a cross of IL 579, a C. chinense introgression line and its recurrent parent 100/63, to the same position as A, suggesting that the two loci are allelic. The two anthocyanin loci were linked to a major quantitative trait locus, fs10.1, for fruit-shape index (ratio of fruit length to fruit width), that also segregated in the F(2) populations. This finding verified the observation of Peterson in 1959 of linkage between fruit color and fruit-shape genes in a cross between round and elongated-fruited parents. The linkage relationship in pepper resembles similar linkage in potato, in which anthocyanin and tuber-shape genes were found linked to each other in a cross of round and elongated-tuber parents. It is therefore possible that the shape pattern of distinct organs such as fruit and tuber in pepper and potato is controlled by a similar gene(s).     

Effects of anthocyanins and anthocyanin-rich extracts on the risk for cancers of the gastrointestinal tract

Anthocyanins are the largest group of water-soluble pigments in the plant kingdom. Anthocyanins are responsible for most of the red, blue, and purple colors of fruits, vegetables, flowers, and other plant tissues or products. In recent years, numerous studies have shown that anthocyanins display a wide range of biological activities. This review summarises recent literature evidence on the association of anthocyanins and anthocyanin-rich extracts consumption with the risk for gastrointestinal tract cancer, concentrating on the results from in vivo animal model tumor systems, as well as data from human epidemiological studies. Potential cancer chemopreventive activities of anthocyanins were revealed from in vitro studies. In vivo animal model tumor systems showed that dietary anthocyanins inhibit cancers of the gastrointestinal tract. Some epidemiological studies have revealed protective effects of anthocyanins consumption on gastrointestinal cancer risk in humans. Pharmacokinetic data indicate that absorption of anthocyanins into the bloodstream of rodents and humans is minimal, suggesting that they may have little efficacy in tissues other than the gastrointestinal tract and skin. Future studies should be undertaken to determine if the anticancer effects of anthocyanins are due to the parent compounds and/or to their metabolites.     

Diversity in plant red pigments: anthocyanins and betacyanins

Plant pigments are of interest for research into questions of basic biology as well as for purposes of applied biology. Red colors in flowers are mainly produced by two types of pigments: anthocyanins and betacyanins. Though anthocyanins are broadly distributed among plants, betacyanins have replaced anthocyanins in the Caryophyllales. Red plant pigments are good indicator metabolites for evolutionary studies of plant diversity as well as for metabolic studies of plant cell growth and differentiation. In this review, we focus on the biosynthesis of anthocyanins and betacyanins and the possible mechanisms underlying the mutual exclusion of betalains and anthocyanins based on the regulation of the biosynthesis of these red pigments.     

Metabolic engineering of anthocyanin biosynthesis in Escherichia coli

Anthocyanins are red, purple, or blue plant pigments that belong to the family of polyphenolic compounds collectively called flavonoids. Their demonstrated antioxidant properties and economic importance to the dye, fruit, and cut-flower industries have driven intensive research into their metabolic biosynthetic pathways. In order to produce stable, glycosylated anthocyanins from colorless flavanones such as naringenin and eriodictyol, a four-step metabolic pathway was constructed that contained plant genes from heterologous origins: flavanone 3beta-hydroxylase from Malus domestica, dihydroflavonol 4-reductase from Anthurium andraeanum, anthocyanidin synthase (ANS) also from M. domestica, and UDP-glucose:flavonoid 3-O-glucosyltransferase from Petunia hybrida. Using two rounds of PCR, each one of the four genes was first placed under the control of the trc promoter and its own bacterial ribosome-binding site and then cloned sequentially into vector pK184. Escherichia coli cells containing the recombinant plant pathway were able to take up either naringenin or eriodictyol and convert it to the corresponding glycosylated anthocyanin, pelargonidin 3-O-glucoside or cyanidin 3-O-glucoside. The produced anthocyanins were present at low concentrations, while most of the metabolites detected corresponded to their dihydroflavonol precursors, as well as the corresponding flavonols. The presence of side product flavonols is at least partly due to an alternate reaction catalyzed by ANS. This is the first time plant-specific anthocyanins have been produced from a microorganism and opens up the possibility of further production improvement by protein and pathway engineering.