12. Lignin Biosynthesis and Lignin Manipulation

The secondary wall is the main part of wood and is composed of cellulose, xylan, lignin, and small amounts of structural proteins and enzymes. Lignin molecules can interact directly or indirectly with cellulose, xylan and other polysaccharide molecules in the cell wall, increasing the mechanical strength and hydrophobicity of plant cells and tissues and facilitating the long-distance transportation of water in plants. MYBs (v-myb avian myeloblastosis viral oncogene homolog) belong to one of the largest superfamilies of transcription factors, the members of which regulate secondary cell-wall formation by promoting/inhibiting the biosynthesis of lignin, cellulose, and xylan. Among them, MYB46 and MYB83, which comprise the second layer of the main switch of secondary cell-wall biosynthesis, coordinate upstream and downstream secondary wall synthesis-related transcription factors. In addition, MYB transcription factors other than MYB46/83, as well as noncoding RNAs, hormones, and other factors, interact with one another to regulate the biosynthesis of the secondary wall. Here, we discuss the biosynthesis of secondary wall, classification and functions of MYB transcription factors and their regulation of lignin polymerization and secondary cell-wall formation during wood formation.

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Integrated transcriptomic and proteomic analysis reveals the complex molecular mechanisms underlying stone cell formation in Korla pear

Scientific Reports ◽

10.1038/s41598-021-87262-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Aisajan Mamat ◽

Kuerban Tusong ◽

Juan Xu ◽

Peng Yan ◽

Chuang Mei ◽

...

Keyword(s):

Cell Differentiation ◽

Proteomic Analysis ◽

Molecular Mechanisms ◽

Developmental Stages ◽

Cell Formation ◽

Parenchyma Cell ◽

Lignin Biosynthesis ◽

Cell Content ◽

Stone Cell ◽

Fruit Samples

AbstractKorla pear (Pyrus sinkiangensis Yü) is a landrace selected from a hybrid pear species in the Xinjiang Autonomous Region in China. In recent years, pericarp roughening has been one of the major factors that adversely affects fruit quality. Compared with regular fruits, rough-skin fruits have a greater stone cell content. Stone cells compose sclerenchyma tissue that is formed by secondary thickening of parenchyma cell walls. In this work, we determined the main components of stone cells by isolating them from the pulp of rough-skin fruits at the ripening stage. Stone cell staining and apoptosis detection were then performed on fruit samples that were collected at three different developmental stages (20, 50 and 80 days after flowering (DAF)) representing the prime, late and stationary stages of stone cell differentiation, respectively. The same batches of samples were used for parallel transcriptomic and proteomic analysis to identify candidate genes and proteins that are related to SCW biogenesis in Korla pear fruits. The results showed that stone cells are mainly composed of cellulose (52%), hemicellulose (23%), lignin (20%) and a small amount of polysaccharides (3%). The periods of stone cell differentiation and cell apoptosis were synchronous and primarily occurred from 0 to 50 DAF. The stone cell components increased abundantly at 20 DAF but then decreased gradually. A total of 24,268 differentially expressed genes (DEGs) and 1011 differentially accumulated proteins (DAPs) were identified from the transcriptomic and proteomic data, respectively. We screened the DEGs and DAPs that were enriched in SCW-related pathways, including those associated with lignin biosynthesis (94 DEGs and 31 DAPs), cellulose and xylan biosynthesis (46 DEGs and 18 DAPs), S-adenosylmethionine (SAM) metabolic processes (10 DEGs and 3 DAPs), apoplastic ROS production (16 DEGs and 2 DAPs), and cell death (14 DEGs and 6 DAPs). Among the identified DEGs and DAPs, 63 significantly changed at both the transcript and protein levels during the experimental periods. In addition, the majority of these identified genes and proteins were expressed the most at the prime stage of stone cell differentiation, but their levels gradually decreased at the later stages.

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Regulation of loquat fruit low temperature response and lignification involves interaction of heat shock factors and genes associated with lignin biosynthesis

Plant Cell & Environment ◽

10.1111/pce.12741 ◽

2016 ◽

Vol 39 (8) ◽

pp. 1780-1789 ◽

Cited By ~ 24

Author(s):

Jiao-ke Zeng ◽

Xian Li ◽

Jing Zhang ◽

Hang Ge ◽

Xue-ren Yin ◽

...

Keyword(s):

Heat Shock ◽

Low Temperature ◽

Temperature Response ◽

Lignin Biosynthesis ◽

Heat Shock Factors

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The response to daylight or continuous ozone of phenylpropanoid and lignin biosynthesis pathways in poplar differs between leaves and wood

Planta ◽

10.1007/s00425-012-1644-8 ◽

2012 ◽

Vol 236 (2) ◽

pp. 727-737 ◽

Cited By ~ 12

Author(s):

Nicolas Richet ◽

Koffi Tozo ◽

Dany Afif ◽

Jacques Banvoy ◽

Sylvain Legay ◽

...

Keyword(s):

Lignin Biosynthesis

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Genome-wide identification and characterization of caffeoyl-coenzyme A O-methyltransferase genes related to the Fusarium head blight response in wheat

BMC Genomics ◽

10.1186/s12864-021-07849-y ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Guang Yang ◽

Wenqiu Pan ◽

Ruoyu Zhang ◽

Yan Pan ◽

Qifan Guo ◽

...

Keyword(s):

Coenzyme A ◽

Expression Patterns ◽

Lignin Biosynthesis ◽

Head Blight ◽

Genome Wide ◽

Genome Search ◽

Gene Structures ◽

Main Components ◽

Main Regulator ◽

Group Sharing

Abstract Background Lignin is one of the main components of the cell wall and is directly associated with plant development and defence mechanisms in plants, especially in response to Fusarium graminearum (Fg) infection. Caffeoyl-coenzyme A O-methyltransferase (CCoAOMT) is the main regulator determining the efficiency of lignin synthesis and composition. Although it has been characterized in many plants, to date, the importance of the CCoAOMT family in wheat is not well understood. Results Here, a total of 21 wheat CCoAOMT genes (TaCCoAOMT) were identified through an in silico genome search method and they were classified into four groups based on phylogenetic analysis, with the members of the same group sharing similar gene structures and conserved motif compositions. Furthermore, the expression patterns and co-expression network in which TaCCoAOMT is involved were comprehensively investigated using 48 RNA-seq samples from Fg infected and mock samples of 4 wheat genotypes. Combined with qRT-PCR validation of 11 Fg-responsive TaCCoAOMT genes, potential candidates involved in the FHB response and their regulation modules were preliminarily suggested. Additionally, we investigated the genetic diversity and main haplotypes of these CCoAOMT genes in bread wheat and its relative populations based on resequencing data. Conclusions This study identified and characterized the CCoAOMT family in wheat, which not only provided potential targets for further functional analysis, but also contributed to uncovering the mechanism of lignin biosynthesis and its role in FHB tolerance in wheat and beyond.

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Effects of Polychlorinated Biphenyls on Lignin Biosynthesis in Arabidopsis thaliana

ACS Agricultural Science & Technology ◽

10.1021/acsagscitech.1c00022 ◽

2021 ◽

Author(s):

Fanella Zamcho ◽

Aaron Newborn ◽

Ayesha Karamat ◽

Rouzbeh Tehrani ◽

Nancy Pleshko ◽

...

Keyword(s):

Arabidopsis Thaliana ◽

Polychlorinated Biphenyls ◽

Lignin Biosynthesis

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Targeting hydroxycinnamoyl CoA: shikimate hydroxycinnamoyl transferase for lignin modification in Brachypodium distachyon

Biotechnology for Biofuels ◽

10.1186/s13068-021-01905-1 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Juan Carlos Serrani-Yarce ◽

Luis Escamilla-Trevino ◽

Jaime Barros ◽

Lina Gallego-Giraldo ◽

Yunqiao Pu ◽

...

Keyword(s):

Negative Impact ◽

Lignin Content ◽

Brachypodium Distachyon ◽

Lignin Biosynthesis ◽

Reverse Direction ◽

Wall Structure ◽

Kinetic Properties ◽

Loss Of Function ◽

Down Regulation ◽

Lignin Modification

Abstract Background Hydroxycinnamoyl CoA: shikimate hydroxycinnamoyl transferase (HCT) is a central enzyme of the so-called “esters” pathway to monolignols. As originally envisioned, HCT functions twice in this pathway, to form coumaroyl shikimate and then, in the “reverse” direction, to convert caffeoyl shikimate to caffeoyl CoA. The discovery of a caffeoyl shikimate esterase (CSE) that forms caffeic acid directly from caffeoyl shikimate calls into question the need for the reverse HCT reaction in lignin biosynthesis. Loss of function of HCT gives severe growth phenotypes in several dicot plants, but less so in some monocots, questioning whether this enzyme, and therefore the shikimate shunt, plays the same role in both monocots and dicots. The model grass Brachypodium distachyon has two HCT genes, but lacks a classical CSE gene. This study was therefore conducted to evaluate the utility of HCT as a target for lignin modification in a species with an “incomplete” shikimate shunt. Results The kinetic properties of recombinant B. distachyon HCTs were compared with those from Arabidopsis thaliana, Medicago truncatula, and Panicum virgatum (switchgrass) for both the forward and reverse reactions. Along with two M. truncatula HCTs, B. distachyon HCT2 had the least kinetically unfavorable reverse HCT reaction, and this enzyme is induced when HCT1 is down-regulated. Down regulation of B. distachyon HCT1, or co-down-regulation of HCT1 and HCT2, by RNA interference led to reduced lignin levels, with only modest changes in lignin composition and molecular weight. Conclusions Down-regulation of HCT1, or co-down-regulation of both HCT genes, in B. distachyon results in less extensive changes in lignin content/composition and cell wall structure than observed following HCT down-regulation in dicots, with little negative impact on biomass yield. Nevertheless, HCT down-regulation leads to significant improvements in biomass saccharification efficiency, making this gene a preferred target for biotechnological improvement of grasses for bioprocessing.

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