The general phenylpropanoid metabolism generates an enormous array of secondary metabolites based on the few intermediates of the shikimate pathway as the core unit. The resulting hydroxycinnamic acids and esters are ...The general phenylpropanoid metabolism generates an enormous array of secondary metabolites based on the few intermediates of the shikimate pathway as the core unit. The resulting hydroxycinnamic acids and esters are am- plified in several cascades by a combination of reductases, oxygenases, and transferases to result in an organ and devel- opmentally specific pattern of metabolites, characteristic for each plant species. During the last decade, methodology driven targeted and non-targeted approaches in several plant species have enabled the identification of the participating enzymes of this complex biosynthetic machinery, and revealed numerous genes, enzymes, and metabolites essential for regulation and compartmentation. Considerable success in structural and computational biology, combined with the an- alytical sensitivity to detect even trace compounds and smallest changes in the metabolite, transcript, or enzyme pattern, has facilitated progress towards a comprehensive view of the plant response to its biotic and abiotic environment. Trans- genic approaches have been used to reveal insights into an apparently redundant gene and enzyme pattern required for functional integrity and plasticity of the various phenylpropanoid biosynthetic pathways. Nevertheless, the function and impact of all members of a gene family remain to be completely established. This review aims to give an update on the various facets of the general phenylpropanoid pathway, which is not only restricted to common lignin or flavonoid biosynthesis, but feeds into a variety of other aromatic metabolites like coumarins, phenolic volatiles, or hydrolyzable tannins.展开更多
In order to understand the physiological and biochemical reasons of leafcolor transformation in Loropetalum chinense var. rubrum,three types of L. chinense var. rubrum, Zihei (black purple), Zihong(red purple)and Hong...In order to understand the physiological and biochemical reasons of leafcolor transformation in Loropetalum chinense var. rubrum,three types of L. chinense var. rubrum, Zihei (black purple), Zihong(red purple)and Hongzhe(red_ochre), and L. chinense were taken as materials. The contents of chlorophyll, carotenoid and soluble sugar, and activity of phenylalanine ammonialyase (PLA) in the leaves were measured from early March to June. The results showed that the contents of chlorophyll, carotenoid and soluble sugar increased gradually during the leafcolor changing from red to green, but there were obviously differences among types of Zihei, Zihong and Hongzhe. Anthocyanins contents in Zihe and Zihong leaves maintained high level, so their leaves still kept red when they got mature in early June. Phenylalanine ammonialyase (PLA) activity decreased, and had positive relationship with anthocyanin contents. Some measures such as shading or watering to lower air temperature could be taken to maintain leaves of L. chinense var. rubrum fresh red during summer.展开更多
文摘The general phenylpropanoid metabolism generates an enormous array of secondary metabolites based on the few intermediates of the shikimate pathway as the core unit. The resulting hydroxycinnamic acids and esters are am- plified in several cascades by a combination of reductases, oxygenases, and transferases to result in an organ and devel- opmentally specific pattern of metabolites, characteristic for each plant species. During the last decade, methodology driven targeted and non-targeted approaches in several plant species have enabled the identification of the participating enzymes of this complex biosynthetic machinery, and revealed numerous genes, enzymes, and metabolites essential for regulation and compartmentation. Considerable success in structural and computational biology, combined with the an- alytical sensitivity to detect even trace compounds and smallest changes in the metabolite, transcript, or enzyme pattern, has facilitated progress towards a comprehensive view of the plant response to its biotic and abiotic environment. Trans- genic approaches have been used to reveal insights into an apparently redundant gene and enzyme pattern required for functional integrity and plasticity of the various phenylpropanoid biosynthetic pathways. Nevertheless, the function and impact of all members of a gene family remain to be completely established. This review aims to give an update on the various facets of the general phenylpropanoid pathway, which is not only restricted to common lignin or flavonoid biosynthesis, but feeds into a variety of other aromatic metabolites like coumarins, phenolic volatiles, or hydrolyzable tannins.
文摘In order to understand the physiological and biochemical reasons of leafcolor transformation in Loropetalum chinense var. rubrum,three types of L. chinense var. rubrum, Zihei (black purple), Zihong(red purple)and Hongzhe(red_ochre), and L. chinense were taken as materials. The contents of chlorophyll, carotenoid and soluble sugar, and activity of phenylalanine ammonialyase (PLA) in the leaves were measured from early March to June. The results showed that the contents of chlorophyll, carotenoid and soluble sugar increased gradually during the leafcolor changing from red to green, but there were obviously differences among types of Zihei, Zihong and Hongzhe. Anthocyanins contents in Zihe and Zihong leaves maintained high level, so their leaves still kept red when they got mature in early June. Phenylalanine ammonialyase (PLA) activity decreased, and had positive relationship with anthocyanin contents. Some measures such as shading or watering to lower air temperature could be taken to maintain leaves of L. chinense var. rubrum fresh red during summer.
