scholarly journals Characterization and functional analysis of the Hydroxycinnamoyl-CoA: shikimate hydroxycinnamoyl transferase (HCT) gene family in poplar

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10741
Author(s):  
Nan Chao ◽  
Qi Qi ◽  
Shuang Li ◽  
Brent Ruan ◽  
Xiangning Jiang ◽  
...  

Hydroxycinnamoyl-CoA: shikimate hydroxycinnamoyl transferase (HCT) divides the mass flux to H, G and S units in monolignol biosynthesis and affects lignin content. Ten HCT homologs were identified in the Populus trichocarpa (Torr. & Gray) genome. Both genome duplication and tandem duplication resulted in the expansion of HCT orthologs in Populus. Comprehensive analysis including motif analysis, phylogenetic analysis, expression profiles and co-expression analysis revealed the divergence and putative function of these candidate PoptrHCTs. PoptrHCT1 and 2 were identified as likely involved in lignin biosynthesis. PoptrHCT9 and 10- are likely to be involved in plant development and the response to cold stress. Similar functional divergence was also identified in Populus tomentosa Carr. Enzymatic assay of PtoHCT1 showed that PtoHCT1 was able to synthesize caffeoyl shikimate using caffeoyl-CoA and shikimic acid as substrates.

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10492
Author(s):  
Ahmed Khadr ◽  
Guang-Long Wang ◽  
Ya-Hui Wang ◽  
Rong-Rong Zhang ◽  
Xin-Rui Wang ◽  
...  

Carrot is an important root vegetable crop abundant in bioactive compounds including carotenoids, vitamins, and dietary fibers. Carrot intake and its products are gradually growing owing to its high antioxidant activity. Auxins are a class of plant hormones that control many processes of plant growth and development. Yet, the effects of exogenous application of auxin on lignin biosynthesis and gene expression profiles of lignin-related genes in carrot taproot are still unclear. In order to investigate the effect of exogenous indole-3-butyric acid (IBA) on lignin-related gene profiles, lignin accumulation, anatomical structures and morphological characteristics in carrot taproots, carrots were treated with different concentrations of IBA (0, 50, 100, and 150 µM). The results showed that IBA application significantly improved the growth parameters of carrot. The 100 or 150 µM IBA treatment increased the number and area of xylem vessels, whereas transcript levels of lignin-related genes were restricted, resulting in a decline in lignin content in carrot taproots. The results indicate that taproot development and lignin accumulation may be influenced by the auxin levels within carrot plants.


2020 ◽  
Author(s):  
Wenqing Zheng ◽  
Liang Du

Abstract Background: The deubiquitinases (DUB) family are a class of enzymes that regulate the stability or reverse the ubiquitination modification of many proteins in the cell, participating in cell cycle regulation, cell division and differentiation, various physiological activities such as DNA damage repair, growth and development, and response to stress. However, little is known about these genes in the woody plants. Results: In the present study, 88 DUB genes were identified in woody model plant Populus trichocarpa, including 44 PtrUBP, 3 PtrUCH, 23 PtrOTU, 4 PtrMJD, and 14 PtrJAMM with similar domains. According to the phylogenetic analysis, the 44 PtrUBP genes were classified into 14 subfamily, three PtrUCHs were classified into two groups, 23 PtrOTUs had six groups, four PtrMJDs had two groups, and 14 PtrJAMMs had six groups. The structure and motif analysis indicated that the same subfamily had similar genome structure and motif distribution characteristics. Ks/Ka analysis showed that the segmental duplication events played a major role in the expansion of Populus DUB genes. Synteny analysis of Populus DUB genes and four other species provided deep perception into the evolutionary traits of DUB genes. Expression profiles derived from transcriptome data exhibited distinct expression patterns of DUB genes in various tissues. Based on the result of promoter cis-regulatory elements analysis, we selected 16 representative PtrUBP genes to test their response to different hormonal treatments. The results showed that most of PtrUBPs were upregulated in the ABA, SA, and MeJA treatments, implying that their potential roles in abiotic stress response in Populus. Conclusion: The results in this study broaden our understanding of the DUB gene family in plants, and the analysis of the structure, conserved elements, and expression patterns of the DUBs provide a solid foundation for exploring their specific functions in Populus as well as indicate potential role of PtrUBP gene in abiotic stress.


2019 ◽  
Author(s):  
Megan L. Matthews ◽  
Jack P. Wang ◽  
Ronald Sederoff ◽  
Vincent L. Chiang ◽  
Cranos M. Williams

AbstractAccurate manipulation of metabolites in the monolignol biosynthetic pathway is a key step for controlling lignin content, structure, and other wood properties important to the bioenergy and biomaterial industries. A crucial component of this strategy is predicting how single and combinatorial knockdowns of monolignol specific gene transcripts influence the abundance of monolignol proteins, which are the driving mechanisms of monolignol biosynthesis. Computational models have been developed to estimate protein abundances from transcript perturbations of monolignol specific genes. The accuracy of these models, however, is hindered by the inability to capture indirect regulatory influences on other pathway genes. Here, we examine the manifestation of these indirect influences collectively on transgenic transcript and protein abundances, identifying putative indirect regulatory influences that occur when one or more specific monolignol pathway genes are perturbed. We created a computational model using sparse maximum likelihood to estimate the resulting monolignol transcript and protein abundances in transgenic Populus trichocarpa based on desired single or combinatorial knockdowns of specific monolignol genes. Using in-silico simulations of this model and root mean square error, we show that our model more accurately estimates transcript and protein abundances in differentiating xylem tissue when individual and families of monolignol genes were perturbed. This approach provides a useful computational tool for exploring the cascaded impact of single and combinatorial modifications of monolignol specific genes on lignin and other wood properties. Additionally, these results can be used to guide future experiments to elucidate the mechanisms responsible for the indirect influences.Author summaryEngineering trees to have desirable lignin and wood traits is of significant interest to the bioenergy and biomaterial industries. Genetically modifying the expression of the genes that drive the monolignol biosynthetic pathway is a useful method for obtaining new traits. Modifying the expression of one gene affects not only the abundance of its encoded protein, but can also indirectly impact the amount of other transcripts and proteins. These proteins drive the monolignol biosynthetic pathway. Having an accurate representation of their abundances is key to understanding how lignin and wood traits are altered. We developed a computational model to estimate how the abundance of monolignol transcripts and proteins are changed when one or more monolignol genes are knocked down. Specifying only the abundances of the targeted genes as input, our model estimates how the levels of the other, untargeted, transcripts and proteins are altered. Our model captures indirect regulatory influences at the transcript and protein levels observed in experimental data. The model is an important addition to current models of lignin biosynthesis. By incorporating our approach into the existing models, we expect to improve our ability to explore how new combinations of gene knockdowns impact lignin and many other wood properties.


2020 ◽  
Author(s):  
Zhixuan Du ◽  
Qitao Su ◽  
Zheng Wu ◽  
Zhou Huang ◽  
Jianzhong Bao ◽  
...  

Abstract Background: Multidrug and toxic compound extrusion (MATE) proteins are involved in many physiological functions of plant growth and development. Although an increasing number of MATE proteins have been identified, the understanding of MATE proteins is still very limited in rice.Results: In this study, 46 MATE proteins were identified from the rice (Oryza sativa) genome by homology searches and domain prediction. In addition, physical and chemical properties of the encoded proteins, subcellular localization, chromosome localization, stress-related cis-elements in abiotic stresses were determined, and a phylogenetic analysis and conserved motif analysis were performed. The rice MATE family can be divided into four subfamilies. It is speculated that members of the rice MATE family have many potential functions, such as the transport and accumulation of flavonoids and alkaloids, the extrusion of plant or exogenous compounds, the regulation of disease resistance and the response to abiotic stress, based on the proteins and cis-acting elements with known functions in the same subfamily. Analysis of gene expression showed that most of the genes were constitutively expressed. Furthermore, eight MATE genes were chosen for qRT-PCR-based analysis and showed differential expression patterns in response to salt and drought stress. Conclusions: Phylogenetic analysis, element prediction, expression data and homology with other species provided strong evidence for functional homology of MATE gene in rice. The analysis results of this study provide comprehensive information on the MATE gene family in rice and will aid in understanding the functional divergence of MATE genes.


2021 ◽  
Vol 12 ◽  
Author(s):  
Chien-Yuan Lin ◽  
Yi Sun ◽  
Jina Song ◽  
Hsi-Chuan Chen ◽  
Rui Shi ◽  
...  

Co-enzyme A (CoA) ligation of hydroxycinnamic acids by 4-coumaric acid:CoA ligase (4CL) is a critical step in the biosynthesis of monolignols. Perturbation of 4CL activity significantly impacts the lignin content of diverse plant species. In Populus trichocarpa, two well-studied xylem-specific Ptr4CLs (Ptr4CL3 and Ptr4CL5) catalyze the CoA ligation of 4-coumaric acid to 4-coumaroyl-CoA and caffeic acid to caffeoyl-CoA. Subsequently, two 4-hydroxycinnamoyl-CoA:shikimic acid hydroxycinnamoyl transferases (PtrHCT1 and PtrHCT6) mediate the conversion of 4-coumaroyl-CoA to caffeoyl-CoA. Here, we show that the CoA ligation of 4-coumaric and caffeic acids is modulated by Ptr4CL/PtrHCT protein complexes. Downregulation of PtrHCTs reduced Ptr4CL activities in the stem-differentiating xylem (SDX) of transgenic P. trichocarpa. The Ptr4CL/PtrHCT interactions were then validated in vivo using biomolecular fluorescence complementation (BiFC) and protein pull-down assays in P. trichocarpa SDX extracts. Enzyme activity assays using recombinant proteins of Ptr4CL and PtrHCT showed elevated CoA ligation activity for Ptr4CL when supplemented with PtrHCT. Numerical analyses based on an evolutionary computation of the CoA ligation activity estimated the stoichiometry of the protein complex to consist of one Ptr4CL and two PtrHCTs, which was experimentally confirmed by chemical cross-linking using SDX plant protein extracts and recombinant proteins. Based on these results, we propose that Ptr4CL/PtrHCT complexes modulate the metabolic flux of CoA ligation for monolignol biosynthesis during wood formation in P. trichocarpa.


Agronomy ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 256 ◽  
Author(s):  
Cecilie S. L. Christensen ◽  
Søren K. Rasmussen

Biomass rich in lignocellulose from grasses is a major source for biofuel production and animal feed. However, the presence of lignin in cell walls limits its efficient utilisation such as in its bioconversion to biofuel. Reduction of the lignin content or alteration of its structure in crop plants have been pursued, either by regulating genes encoding enzymes in the lignin biosynthetic pathway using biotechnological techniques or by breeding naturally-occurring low lignin mutant lines. The aim of this review is to provide a summary of these studies, focusing on lignin (monolignol) biosynthesis and composition in grasses and, where possible, the impact on recalcitrance to bioconversion. An overview of transgenic crops of the grass family with regulated gene expression in lignin biosynthesis is presented, including the effect on lignin content and changes in the ratio of p-hydroxyphenyl (H), guaiacyl (G) and syringyl (S) units. Furthermore, a survey is provided of low-lignin mutants in grasses, including cereals in particular, summarising their origin and phenotypic traits together with genetics and the molecular function of the various genes identified.


2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Xiaofei Zeng ◽  
Jiajing Sheng ◽  
Fenglin Zhu ◽  
Tianzi Wei ◽  
Lingling Zhao ◽  
...  

Abstract Background Miscanthus × giganteus is widely recognized as a promising lignocellulosic biomass crop due to its advantages of high biomass production, low environmental impacts, and the potential to be cultivated on marginal land. However, the high costs of bioethanol production still limit the current commercialization of lignocellulosic bioethanol. The lignin in the cell wall and its by-products released in the pretreatment step is the main component inhibiting the enzymatic reactions in the saccharification and fermentation processes. Hence, genetic modification of the genes involved in lignin biosynthesis could be a feasible strategy to overcome this barrier by manipulating the lignin content and composition of M. × giganteus. For this purpose, the essential knowledge of these genes and understanding the underlying regulatory mechanisms in M. × giganteus is required. Results In this study, MgPAL1, MgPAL5, Mg4CL1, Mg4CL3, MgHCT1, MgHCT2, MgC3′H1, MgCCoAOMT1, MgCCoAOMT3, MgCCR1, MgCCR2, MgF5H, MgCOMT, and MgCAD were identified as the major monolignol biosynthetic genes in M. × giganteus based on genetic and transcriptional evidence. Among them, 12 genes were cloned and sequenced. By combining transcription factor binding site prediction and expression correlation analysis, MYB46, MYB61, MYB63, WRKY24, WRKY35, WRKY12, ERF021, ERF058, and ERF017 were inferred to regulate the expression of these genes directly. On the basis of these results, an integrated model was summarized to depict the monolignol biosynthesis pathway and the underlying regulatory mechanism in M. × giganteus. Conclusions This study provides a list of potential gene targets for genetic improvement of lignocellulosic biomass quality of M. × giganteus, and reveals the genetic, transcriptional, and regulatory landscape of the monolignol biosynthesis pathway in M. × giganteus.


2019 ◽  
Vol 39 (12) ◽  
pp. 2019-2026
Author(s):  
Nan Chao ◽  
Wen-Ting Jiang ◽  
Xue-Chun Wang ◽  
Xiang-Ning Jiang ◽  
Ying Gai

Abstract Cinnamoyl-coenzyme A reductases (CCRs) have been reported as key enzymes involved in monolignol biosynthesis. In this study, a motif-aware workflow based on a new signature motif effectively distinguished CCRs from CCR-like proteins. The divergence of CCRs and CCR-like sequences in Populus tomentosa Carr, Panicum virgatum L, Oryza sativa L and Selaginella moellendorffii Hieron suggests that NWYCY is not efficient for CCR recognition. The novel motif H202(X)2K205 (CCR-SBM or CCR substrate binding motif) was introduced to distinguish between CCRs and CCR-like proteins. The site-directed mutant R205K in Os(I)CCR-like and H202 in PtoCCR7 resulted in the rescue and loss of activity, respectively, further validating the fact that CCR-SBM is critical for maintaining CCR activity. The molecular docking using feruloyl-cinnamoyl-coenzyme A (CoA) as the ligand and binary PhCCR-NADP structures as receptors indicated an interaction between H202 and K205 with CoA moiety. The genuine CCRs and CCR-like proteins from several angiosperms and gymnosperms were screened using a motif-aware workflow and were validated using a biochemical assay. Our results suggest that the motif-aware workflow is efficient and effective for the identification of CCRs and CCR-like proteins in land plants and can be used as a more accurate way of identifying genuine CCRs among land plants.


2014 ◽  
Vol 68 ◽  
pp. 228-239 ◽  
Author(s):  
Anna T. Stout ◽  
Aletta A. Davis ◽  
Jean-Christophe Domec ◽  
Chenmin Yang ◽  
Rui Shi ◽  
...  

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Shifei Qin ◽  
Chunfen Fan ◽  
Xiaohong Li ◽  
Yi Li ◽  
Jian Hu ◽  
...  

Abstract Background The recalcitrance of lignocellulosic biomass provided technical and economic challenges in the current biomass conversion processes. Lignin is considered as a crucial recalcitrance component in biomass utilization. An in-depth understanding of lignin biosynthesis can provide clues to overcoming the recalcitrance. Laccases are believed to play a role in the oxidation of lignin monomers, leading to the formation of higher-order lignin. In plants, functions of only a few laccases have been evaluated, so little is known about the effect of laccases on cell wall structure and biomass saccharification. Results In this study, we screened a gain-of-function mutant with a significant increase in lignin content from Arabidopsis mutant lines overexpressing a full-length poplar cDNA library. Further analysis confirmed that a Chinese white poplar (Populus tomentosa) laccase gene PtoLAC14 was inserted into the mutant, and PtoLAC14 could functionally complement the Arabidopsis lac4 mutant. Overexpression of PtoLAC14 promoted the lignification of poplar and reduced the proportion of syringyl/guaiacyl. In contrast, the CRISPR/Cas9-generated mutation of PtLAC14 results in increased the syringyl/guaiacyl ratios, which led to integrated enhancement on biomass enzymatic saccharification. Notably, the recombinant PtoLAC14 protein showed higher oxidized efficiency to coniferyl alcohol (precursor of guaiacyl unit) in vitro. Conclusions This study shows that PtoLAC14 plays an important role in the oxidation of guaiacyl deposition on cell wall. The reduced recalcitrance of the PtoLAC14-KO lines suggests that PtoLAC14 is an elite target for cell wall engineering, and genetic manipulation of this gene will facilitate the utilization of lignocellulose.


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