The comparative analysis of the monolignols localization in epidermis, photosynthesizing parenchyma and vessels walls of Myriophyllum spicatum, Potamogeton pectinatus and P. perfoliatus submerged leaves carried out on...The comparative analysis of the monolignols localization in epidermis, photosynthesizing parenchyma and vessels walls of Myriophyllum spicatum, Potamogeton pectinatus and P. perfoliatus submerged leaves carried out on the basis of cytochemical method and laser confocal microscopy. The images of quantitative distribution of syringyl and guaiacyl in the cell walls were obtained at cellular level depending on the type of leaf tissues and plant species. The increase of relative content of monolignols was established in walls of vessels and in the corners of parenchyma cells. Cytochemical analysis indicates that ratio of syringyl/guaiacyl in leaf tissues changes depending on species. The role of of syringyl and guaiacyl monolignols in the cellular mechanisms of adaptation to nature flooding is discussed.展开更多
The cell wall in wood is mainly composed of three components: cellulose, hemicellulose and lignin. According to electron microscopy observations of the innermost surface of cell walls in the tracheids of Cryptomeria j...The cell wall in wood is mainly composed of three components: cellulose, hemicellulose and lignin. According to electron microscopy observations of the innermost surface of cell walls in the tracheids of Cryptomeria japonica , cellulose microfibrils are deposited during the day and a matrix containing hemicellulose is deposited at night. This indicates that the deposition of cell wall components exhibits diurnal periodicity. To gain new insights into the diurnal periodicity of lignin deposition not revealed by microscopic observations, we examined diurnal fluctuations in the expression of genes involved in monolignol biosynthesis in C. japonica saplings grown in the field and in growth chambers under a 12 h light/dark cycle. In the field experiment, two gene expression peaks were observed daily, at dusk and dawn. In the growth chamber experiment, two daily peaks were observed 0 h and 6 - 9 h after the light switched on.展开更多
Phenylpropanoid-derived compounds represent a diverse family of secondary metabolites that originate from phenylalanine. These compounds have roles in plant growth and development, and in defense against biotic and ab...Phenylpropanoid-derived compounds represent a diverse family of secondary metabolites that originate from phenylalanine. These compounds have roles in plant growth and development, and in defense against biotic and abiotic stress. Many of these compounds are also beneficial to human health and welfare. V-myb myeloblastosis viral oncogene homolog （MYB） proteins belong to a large family of transcription factors and are key regulators of the synthesis of phenylpropanoid-derived compounds. This review summarizes the current understanding of MYB proteins and their roles in the regulation of phenylpropanoid metabolism in plants.展开更多
Plant lignification is a tightly regulated complex cellular process that occurs via three sequential steps： the synthesis of monolignols within the cytosol; the transport of monomeric precursors across plasma membran...Plant lignification is a tightly regulated complex cellular process that occurs via three sequential steps： the synthesis of monolignols within the cytosol; the transport of monomeric precursors across plasma membrane; and the oxidative polymerization of monolignols to form lignin macromolecules within the cell wall. Although we have a reasonable understanding of monolignol biosynthesis, many aspects of lignin assembly remain elusive. These include the pre- cursors＇ transport and oxidation, and the initiation of lignin polymerization. This review describes our current knowledge of the molecular mechanisms underlying monolignol transport and oxidation, discusses the intriguing yet least- understood aspects of lignin assembly, and highlights the technologies potentially aiding in clarifying the enigma of plant lignification.展开更多
文摘The comparative analysis of the monolignols localization in epidermis, photosynthesizing parenchyma and vessels walls of Myriophyllum spicatum, Potamogeton pectinatus and P. perfoliatus submerged leaves carried out on the basis of cytochemical method and laser confocal microscopy. The images of quantitative distribution of syringyl and guaiacyl in the cell walls were obtained at cellular level depending on the type of leaf tissues and plant species. The increase of relative content of monolignols was established in walls of vessels and in the corners of parenchyma cells. Cytochemical analysis indicates that ratio of syringyl/guaiacyl in leaf tissues changes depending on species. The role of of syringyl and guaiacyl monolignols in the cellular mechanisms of adaptation to nature flooding is discussed.
文摘The cell wall in wood is mainly composed of three components: cellulose, hemicellulose and lignin. According to electron microscopy observations of the innermost surface of cell walls in the tracheids of Cryptomeria japonica , cellulose microfibrils are deposited during the day and a matrix containing hemicellulose is deposited at night. This indicates that the deposition of cell wall components exhibits diurnal periodicity. To gain new insights into the diurnal periodicity of lignin deposition not revealed by microscopic observations, we examined diurnal fluctuations in the expression of genes involved in monolignol biosynthesis in C. japonica saplings grown in the field and in growth chambers under a 12 h light/dark cycle. In the field experiment, two gene expression peaks were observed daily, at dusk and dawn. In the growth chamber experiment, two daily peaks were observed 0 h and 6 - 9 h after the light switched on.
文摘Phenylpropanoid-derived compounds represent a diverse family of secondary metabolites that originate from phenylalanine. These compounds have roles in plant growth and development, and in defense against biotic and abiotic stress. Many of these compounds are also beneficial to human health and welfare. V-myb myeloblastosis viral oncogene homolog （MYB） proteins belong to a large family of transcription factors and are key regulators of the synthesis of phenylpropanoid-derived compounds. This review summarizes the current understanding of MYB proteins and their roles in the regulation of phenylpropanoid metabolism in plants.
基金This work was supported by the Division of Chemical Sciences, Geosciences, and Biosciences, Office of Basic Energy Sciences of the US Department of Energy through Grant DEAC0298CH10886 the National Science Foundation through grant MCB-1051675+1 种基金 the Laboratory Directed Research and Development Program of Brookhaven National Laboratory （No 11-007） the CAS/SAFEA International Partnership Program for Creative Research Teams in Plant Metabolisms, and the National Science Foundation of China for Oversea Distin- guished Young Scholars （31028003）. No conflict of interest declared.
文摘Plant lignification is a tightly regulated complex cellular process that occurs via three sequential steps： the synthesis of monolignols within the cytosol; the transport of monomeric precursors across plasma membrane; and the oxidative polymerization of monolignols to form lignin macromolecules within the cell wall. Although we have a reasonable understanding of monolignol biosynthesis, many aspects of lignin assembly remain elusive. These include the pre- cursors＇ transport and oxidation, and the initiation of lignin polymerization. This review describes our current knowledge of the molecular mechanisms underlying monolignol transport and oxidation, discusses the intriguing yet least- understood aspects of lignin assembly, and highlights the technologies potentially aiding in clarifying the enigma of plant lignification.
