P-coumaryl Alcohol Research Articles

Resolving the metabolism of monolignols and other lignin-related aromatic compounds in Xanthomonas citri

Lignin, a major plant cell wall component, has an important role in plant-defense mechanisms against pathogens and is a promising renewable carbon source to produce bio-based chemicals. However, our understanding of microbial metabolism is incomplete regarding certain lignin-related compounds like p-coumaryl and sinapyl alcohols. Here, we reveal peripheral pathways for the catabolism of the three main lignin precursors (p-coumaryl, coniferyl, and sinapyl alcohols) in the plant pathogen Xanthomonas citri. Our study demonstrates all the necessary enzymatic steps for funneling these monolignols into the tricarboxylic acid cycle, concurrently uncovering aryl aldehyde reductases that likely protect the pathogen from aldehydes toxicity. It also shows that lignin-related aromatic compounds activate transcriptional responses related to chemotaxis and flagellar-dependent motility, which might play an important role during plant infection. Together our findings provide foundational knowledge to support biotechnological advances for both plant diseases treatments and conversion of lignin-derived compounds into bio-based chemicals.

Physiological-Biochemical Characteristics and a Transcriptomic Profiling Analysis Reveal the Postharvest Wound Healing Mechanisms of Sweet Potatoes under Ascorbic Acid Treatment.

Sweet potatoes are extremely vulnerable to mechanical wounds during harvesting and postharvest handling. It is highly necessary to take measures to accelerate wound healing. The effect of 20 g L-1 of ascorbic acid (AA) treatment on the wound healing of sweet potatoes and its mechanisms were studied. The results validated that AA treatment significantly reduced the weight loss rate and disease index. AA treatment effectively enhanced the formation speed of lignin and SPP at the wound sites, decreased the MDA content, and maintained the cell membrane integrity. AA enhanced the activities of PAL, C4H, 4CL, CAD, and POD and increased the contents of chlorogenic acid, caffeic acid, sinapic acid, ferulic acid, cinnamic acid, p-coumaryl alcohol, sinapyl alcohol, coniferyl alcohol, and lignin. Based on a transcriptomic analysis, a total of 1200 genes were differentially expressed at the sweet potato wound sites by the AA treatment, among which 700 genes were upregulated and 500 genes were downregulated. The KEGG pathway analysis showed that the differentially expressed genes were mainly involved in phenylalanine, tyrosine, and tryptophan biosynthesis; phenylpropanoid biosynthesis; and other wound healing-related pathways. As verified by a qRT-PCR, the AA treatment significantly upregulated the gene expression levels of IbSKDH, IbADT/PDT, IbPAL, and Ib4CL at the wound sties.

Whole-Cell Bioconversion Systems for Efficient Synthesis of Monolignols from L-Tyrosine in Escherichia coli.

Monolignols and their derivatives exhibit various pharmaceutical and physiological characteristics, such as antioxidant and anti-inflammatory properties. However, they remain difficult to synthesize. In this study, we engineered several whole-cell bioconversion systems with carboxylate reductase (CAR)-mediated pathways for efficient synthesis of p-coumaryl, caffeyl, and coniferyl alcohols from l-tyrosine in Escherichia coli BL21 (DE3). By overexpressing the l-tyrosine ammonia lyase from Flavobacterium johnsoniae (FjTAL), carboxylate reductase from Segniliparus rugosus (SruCAR), alcohol dehydrogenase YqhD and hydroxylase HpaBC from E. coli, and caffeate 3-O-methyltransferase (COMT) from Arabidopsis thaliana, three enzyme cascades FjTAL-SruCAR-YqhD, FjTAL-SruCAR-YqhD-HpaBC, and FjTAL-SruCAR-YqhD-HpaBC-COMT were constructed to produce 1028.5 mg/L p-coumaryl alcohol, 1015.3 mg/L caffeyl alcohol, and 411.4 mg/L coniferyl alcohol from 1500, 1500, and 1000 mg/L l-tyrosine, with productivities of 257.1, 203.1, and 82.3 mg/L/h, respectively. This work provides an efficient strategy for the biosynthesis of p-coumaryl, caffeyl, and coniferyl alcohols from l-tyrosine.

Integrated metabolomic and transcriptomic analysis reveals the regulatory mechanisms of flavonoid and alkaloid biosynthesis in the new and old leaves of Murraya tetramera Huang

BackgroundMurraya tetramera Huang is a traditional Chinese woody medicine. Its leaves contain flavonoids, alkaloids, and other active compounds, which have anti-inflammatory and analgesic effects, as well as hypoglycemic and lipid-lowering effects, and anti-tumor effects. There are significant differences in the content of flavonoids and alkaloids in leaves during different growth cycles, but the synthesis mechanism is still unclear.ResultsIn April 2021, new leaves (one month old) and old leaves (one and a half years old) of M. tetramera were used as experimental materials to systematically analyze the changes in differentially expressed genes (DEGs) and differentially accumulated metabolites (DAMs) with transcriptomics and metabolomics technology. This was done to identify the signaling pathways of flavonoid and alkaloid synthesis. The results showed that the contents of total alkaloids and flavonoids in old leaves were significantly higher than those in new leaves. Thirteen flavonoid compounds, three isoflavone compounds, and nineteen alkaloid compounds were identified, and 125 and 48 DEGs related to flavonoid and alkaloid synthesis were found, respectively. By constructing the KEGG (Kyoto Encyclopedia of Genes and Genomes) network of DEGs and DAMs, it was shown that the molecular mechanism of flavonoid biosynthesis in M. tetramera mainly focuses on the “flavonoid biosynthetic pathway” and the “flavonoid and flavonol biosynthetic pathway”. Among them, p-Coumaryl alcohol, Sinapyl alcohol, Phloretin, and Isoquercitrin were significantly accumulated in old leaves, the up-regulated expression of CCR (cinnamoyl-CoA reductase) might promote the accumulation of p-Coumaryl alcohol, upregulation of F5H (ferulate-5-hydroxylase) might promote Sinapyl alcohol accumulation. Alkaloids, including indole alkaloids, pyridine alkaloids, imidazole alkaloids, and quinoline alkaloids, were significantly accumulated in old leaves, and a total of 29 genes were associated with these substances.ConclusionsThese data are helpful to better understand the biosynthesis of flavonoids and alkaloids in M. tetramera and provide a scientific basis for the development of medicinal components in M. tetramera.

A Preliminary Study on the Identification of Genes Involved in Lignification in the Endocarp of Bared-Nut Walnut (Juglans regia L.) in Xinjiang, China

This study focused on the “Xinlu” walnut and explored the molecular regulatory mechanism of lignin synthesis in the endocarp, aiming to explain the formation of bared-nut walnuts through morphological, metabolomic, and transcriptomic techniques. It was found that the synthesis of lignin, cellulose, p-coumaryl alcohol, and sinapyl alcohol was severely inhibited in the pulpy-hue (PUH) of the endocarp. We obtained 14 modules (gene sets) significantly correlated with the lignification factor (LIG) and 1548 hub genes. Additionally, we identified a MEplum3 module involved in endocarp lignin synthesis, primarily participating in phenylalanine biosynthesis and the lignin biosynthetic process. Meanwhile, we constructed a gene co-expression network for the MEplum3 module and identified a key hub gene for lignin synthesis—JrCAD10. Among the different tissues of “Xinlu”, the expression level of JrCAD10 in the scleritic-hue (SCH) was significantly higher than in other tissues, with a relative copy number (RCN) of 3.2. However, JrCAD10 expression was severely suppressed in the PUH. The suppression of JrCAD10 expression led to the inhibition of lignin monomer synthesis, which further resulted in inhibited lignin synthesis, thus forming the bared-nut walnut. Our findings provide new insights into understanding the regulation of lignin synthesis and offer a possible explanation for the formation of bared-nut walnuts.

Exploring Caffeic Acid and Lignosulfonate as Key Phenolic Ligands for Metal-Phenolic Network Assembly.

Films formed by metals and phenols through a coordinative interaction have been extensively studied in previous years. We report the successful formation of MPN films from the phenolic compounds caffeic acid and lignosulfonate using Fe3+ ions for complexation. The likewise examined p-coumaryl alcohol showed some MPN film formation tendency, while for coniferyl alcohol and sinapyl alcohol, no successful film buildup could be observed. These newly formed films were compared to tannic acid-Fe3+ films as a reference. Film growth and degradation were tracked by using UV-vis absorption spectroscopy. The films were degradable under different conditions such as alkaline environments or in the presence of a strong chelator. Small hollow capsules with a diameter of 3 μm and thicknesses in the nanometer range were produced. Additionally, the prepared films showed varying colors and levels of wettability. By utilizing the films' coating properties, we successfully dyed human hair in various colors.

Unrevealing the Enhanced Laccase Activities of Phlebiopsis flavidoalba in the Presence of Lignin-Rich Raw Materials using Molecular Docking

Laccase, a versatile enzyme that belongs to the multi-copper oxidase family, exhibits extraordinary lignin-degrading capabilities. Among the diverse types of laccases, white-rot fungal laccases are considered some of the best lignin degraders, with various biotechnological and industrial applications. In our previous study, it was found that a wood-decaying white rot fungus, Phlebiopsis flavidoalba, is one of the highest laccase producers in vitro in the presence of rice husks as the raw material. However, it is unclear the exact mechanism and whether laccase directly interacts with the raw material, in this case, rice husks and its lignin model compound. Hence, the objective of the current study was to obtain laccase gene sequence from P. flavidoalba and subject it to molecular docking with lignin model compounds that are particularly found in rice husks to determine binding affinities to the active sites of enzyme. The laccase gene sequence of P. flavidoalba was obtained from the next-generation sequence data set obtained in our previous study and subjected to in silico homology modelling and molecular docking using various lignin model compounds reported to be present in rice husks. Firstly, to predict the 3D structure of the laccase of P. flavidoalba, homology modelling was performed using SWISS-MODEL. Laccase from Steccherinum murashkinskyi was selected as the template for homology modelling using SWISS-MODEL. CB-Dock server was used to perform molecular docking studies with a range of lignin model compounds, including sinapyl alcohol, coniferyl alcohol, 𝜌- coumaryl alcohol, β-O-4′ aryl ether, β-5′ phenylcoumaran which are commonly found in rice husks. It was found that the above-mentioned lignin model compounds exhibited strong binding affinities such as -5.9 kcal/mol (sinapyl alcohol), -6.5 kcal/mol (coniferyl alcohol), -8.6 kcal/mol (𝜌- coumaryl alcohol), -7.5 kcal/mol (β-O-4′ aryl ether), and -7.5 kcal/mol (β-5′ phenylcoumaran) with the laccase protein of P. flavidoalba. The amino acid residues of modelled laccase in contact with the lignin model compounds forming hydrogen bonds were Gln457, Ile434, Phe432, Arg370, Lys452, Ile365. The insights gained from these docking studies can help uncover the molecular level interactions and the potential of utilizing such low-cost carbon sources for boosting laccase production.
 
 Keywords: Homology modelling, Laccase, Lignin model compounds, Molecular docking, Rice husk

PEG-6000 Priming Improves Aged Soybean Seed Vigor via Carbon Metabolism, ROS Scavenging, Hormone Signaling, and Lignin Synthesis Regulation

Seed priming, a valuable seed pretreatment method widely employed in agricultural production, counteracts the decline in seed vigor attributed to aging and deterioration. However, PEG priming effectively enhances the vigor of aged soybean seeds. In this study, “TONGDOU13” soybean seeds were subjected to PEG-6000 priming at varying concentrations (10%, 20%, 30%, 40%) for three different durations (12 h, 24 h, 36 h). The results showed that a 24 h priming with 30% PEG-6000 significantly enhances the vigor of aged soybean seeds. To elucidate the mechanism underlying the heightened vigor resulting from PEG-6000 priming, we employed transcriptome sequencing and physiological–biochemical tests. Transcriptome sequencing analysis showed the significant down-regulation of carbon metabolism-related genes post PEG-6000 priming, which facilitated energetically efficient germination. Five peroxidase-encoding genes displayed significant up-regulation, promoting the conversion of coumaryl alcohol to hydroxy-phenyl lignin, a probable catalyst for augmented seed vigor. SOD and GST genes were significantly up-regulated, enhancing the scavenging ability of reactive oxygen species (ROS). The concurrent up-regulation of brassinolide (BR) and auxin (IAA) signals countered ABA signaling, thereby promoting aged seed germination. Further investigation included the measurements of antioxidant enzyme activity, hormone levels, and lignin content. Notably, primed aged seeds exhibited enhanced ROS scavenging ability, and increased lignin, BR, and IAA contents. Therefore, PEG priming may improve aged soybean seed vigor through the co-regulation of carbon metabolism, ROS scavenging, hormone signaling, and lignin synthesis. This study will be vital for preserving germplasm resources and reutilizing aged soybean seeds.

Multi-omics analysis reveals activation of jasmonate synthesis and modulation of oxidative stress responses in boron deficient pea shoots

Boron (B) is vital for plant growth and development. Understanding aboveground tissue responses to B deficiency can offer insights into enhancing plant productivity under B-limited conditions. Here we show from comprehensive metabolomics analysis that during B deficiency treatment the number of differentially expressed metabolites (DEMs) increases from 64 to 193 in pea shoots. Boron deficiency intensified oxidative stress and led to decreased ascorbate and glutathione levels. Integrative metabolomic and transcriptomic analyses revealed activation of the phenylpropanoid biosynthesis and α-linolenic acid metabolic pathways under B deficiency. Metabolites of the phenylpropanoid pathway, including p-coumaryl alcohol and sinapic acid, increased, accompanied by upregulation of related biosynthetic genes. A decline in total flavonoid content suggested that the activation of phenylpropanoid synthesis might indicate increased lignin accumulation, thus affecting cell wall metabolism. The alterations in these pathways at specific time point highlighted the dynamic resource allocation caused by B deficiency, providing insights into metabolic reprogramming in pea shoot apices. In the α-linolenic acid pathway, B deficiency led to accumulation of 17-hydroxylinolenic acid, jasmonic acid (JA), and jasmonoyl-L-isoleucine, with upregulated JA biosynthesis genes. Jasmonates are proposed to play a key role in reprogramming shoot development particularly modulating membrane and cell wall structure and function under B deficiency. Increased levels of oxidation products of linoleic acid suggest changes to membrane structure and are also consistent with changes to the redox status of cells under B deficiency. Collectively, our findings elucidated intricate B deficiency responses at both the metabolome and transcriptome levels and identified potential targets for breeding crops tolerant to B deficiency, including jasmonate signalling, phenylpropanoid biosynthesis, and antioxidant capacity.

Corn straw lignin — A sustainable bioinspired finish for superhydrophobic and UV-protective cellulose fabric

Hydrophobic textiles have been considered extensively for self-cleaning, phase-separating, and biomedical curing applications. We focused on preparing an eco-friendly lignin-based bio-finish to develop superhydrophobic cellulose fabric under mild conditions. The mass spectroscopic analysis expressed that the lignin comprised the major constituents of p-coumaryl alcohol, ferulic acid, coniferyl alcohol, and sinapyl alcohol. The surface morphological analysis indicated the formation of a regular lignin coating on the cellulose fabric. The bio-finished cellulose fabric prepared (at 2 %, w/v, lignin) expressed the maximum water contact angle (WCA) of 157.2° and remained in the hydrophobic range (119°) after ten standard washes. The treated fabric expressed the WCA values of 135.0 and 133.0° after exposure to pH 2 and 12 aqueous media, respectively. The infrared spectroscopic analysis indicated the functional chemistry of the precursors involved and possible alteration in their chemical interactions during processing. The lignin-treated cellulose was observed to be less crystalline as compared to the untreated one. Such fabric expressed acceptable comfort, sensorial properties, and thermal stability up to 333 °C. The treated fabrics could block up to 92.24 % UV-A and 98.62 % UV-B radiations. Consequently, the lignin-based finish sourced from wasted corn straw was found cost-effective and efficient for producing superhydrophobic cellulose fabric.

Carboxylic acid reductase-dependent biosynthesis of eugenol and related allylphenols

Background(Hydroxy)cinnamyl alcohols and allylphenols, including coniferyl alcohol and eugenol, are naturally occurring aromatic compounds widely utilised in pharmaceuticals, flavours, and fragrances. Traditionally, the heterologous biosynthesis of (hydroxy)cinnamyl alcohols from (hydroxy)cinnamic acids involved CoA-dependent activation of the substrate. However, a recently explored alternative pathway involving carboxylic acid reductase (CAR) has proven efficient in generating the (hydroxy)cinnamyl aldehyde intermediate without the need for CoA activation. In this study, we investigated the application of the CAR pathway for whole-cell bioconversion of a range of (hydroxy)cinnamic acids into their corresponding (hydroxy)cinnamyl alcohols. Furthermore, we sought to extend the pathway to enable the production of a variety of allylphenols and allylbenzene.ResultsBy screening the activity of several heterologously expressed enzymes in crude cell lysates, we identified the combination of Segniliparus rugosus CAR (SrCAR) and Medicago sativa cinnamyl alcohol dehydrogenase (MsCAD2) as the most efficient enzymatic cascade for the two-step reduction of ferulic acid to coniferyl alcohol. To optimise the whole-cell bioconversion in Escherichia coli, we implemented a combinatorial approach to balance the gene expression levels of SrCAR and MsCAD2. This optimisation resulted in a coniferyl alcohol yield of almost 100%. Furthermore, we extended the pathway by incorporating coniferyl alcohol acyltransferase and eugenol synthase, which allowed for the production of eugenol with a titre of up to 1.61 mM (264 mg/L) from 3 mM ferulic acid. This improvement in titre surpasses previous achievements in the field employing a CoA-dependent coniferyl alcohol biosynthesis pathway. Our study not only demonstrated the successful utilisation of the CAR pathway for the biosynthesis of diverse (hydroxy)cinnamyl alcohols, such as p-coumaryl alcohol, caffeyl alcohol, cinnamyl alcohol, and sinapyl alcohol, from their corresponding (hydroxy)cinnamic acid precursors but also extended the pathway to produce allylphenols, including chavicol, hydroxychavicol, and methoxyeugenol. Notably, the microbial production of methoxyeugenol from sinapic acid represents a novel achievement.ConclusionThe combination of SrCAR and MsCAD2 enzymes offers an efficient enzymatic cascade for the production of a wide array of (hydroxy)cinnamyl alcohols and, ultimately, allylphenols from their respective (hydroxy)cinnamic acids. This expands the range of value-added molecules that can be generated using microbial cell factories and creates new possibilities for applications in industries such as pharmaceuticals, flavours, and fragrances. These findings underscore the versatility of the CAR pathway, emphasising its potential in various biotechnological applications.

Meyerozyma guilliermondii promoted the deposition of GSH type lignin by activating the biosynthesis and polymerization of monolignols at the wounds of potato tubers

Lignin is a crucial component in the wound tissue of tubers. The biocontrol yeast Meyerozyma guilliermondii increased the activities of phenylalanine ammonia lyase, cinnamate-4-hydroxylase, 4-coenzyme coenzyme A ligase, and cinnamyl alcohol dehydrogenase, and elevated the levels of coniferyl, sinapyl, and p-coumaryl alcohol. The yeast also enhanced the activities of peroxidase and laccase, as well as the content of hydrogen peroxide. The lignin promoted by the yeast was identified as guaiacyl-syringyl-p-hydroxyphenyl type using Fourier transform infrared spectroscopy and two-dimensional heteronuclear single quantum coherence nuclear magnetic resonance. Furthermore, a larger signal area for G2, G5, G'6, S2, 6, and S'2, 6 units was observed in the treated tubers, and the G'2 and G6 units were only detected in the treated tuber. Taken together, M. guilliermondii could promote deposition of guaiacyl-syringyl-p-hydroxyphenyl type lignin by activating the biosynthesis and polymerization of monolignols at the wounds of potato tubers.

Integrated transcriptomic and metabolomic analysis reveals the effects of polyploidization on the lignin content and metabolic pathway in Eucalyptus

BackgroundLignin is a major restriction factor for the industrial production of biomass resources, such as pulp and bioenergy. Eucalyptus is one of the most important sources of pulp and bioenergy. After polyploidization, the lignin content of forest trees is generally reduced, which is considered a beneficial genetic improvement. However, the differences in the lignin content between triploid and diploid Eucalyptus and the underlying regulatory mechanism are still unclear.ResultsWe conducted a comprehensive analysis at the phenotypic, transcriptional and metabolite levels between Eucalyptus urophylla triploids and diploids to reveal the effects of polyploidization on the lignin content and lignin metabolic pathway. The results showed that the lignin content of Eucalyptus urophylla triploid stems was significantly lower than that of diploids. Lignin-related metabolites were differentially accumulated between triploids and diploids, among which coniferaldehyde, p-coumaryl alcohol, sinapaldehyde and coniferyl alcohol had significant positive correlations with lignin content, indicating that they might be primarily contributing metabolites. Most lignin biosynthetic genes were significantly downregulated, among which 11 genes were significantly positively correlated with the lignin content and above metabolites. Furthermore, we constructed a co-expression network between lignin biosynthetic genes and transcription factors based on weighted gene co-expression network analysis. The network identified some putative orthologues of secondary cell wall (SCW)-related transcription factors, among which MYB52, MYB42, NAC076, and LBD15 were significantly downregulated in Eucalyptus urophylla triploids. In addition, potential important transcription factors, including HSL1, BEE3, HHO3, and NAC046, also had high degrees of connectivity and high edge weights with lignin biosynthetic genes, indicating that they might also be involved in the variation of lignin accumulation between triploid and diploid Eucalyptus urophylla.ConclusionsThe results demonstrated that some lignin-related metabolites, lignin biosynthetic genes and transcription factors in Eucalyptus urophylla triploids may be relatively sensitive in response to the polyploidization effect, significantly changing their expression levels, which ultimately correlated with the varied lignin content. The analysis of the underlying formation mechanism could provide beneficial information for the development and utilization of polyploid biomass resources, which will be also valuable for genetic improvement in other bioenergy plants.

Uncovering mechanisms governing stem growth in peanut (Arachis hypogaea L.) with varying plant heights through integrated transcriptome and metabolomics analyses

The mechanisms responsible for stem growth in peanut (Arachis hypogaea L.) cultivars with varying plant heights remain unclear, despite the significant impact of plant height on peanut yield. Therefore, this study aimed to investigate the underlying mechanisms of peanut stem growth using phenotypic, physiological, transcriptomic, and metabolomic analyses. The findings revealed that the tallest cultivar, HY33, exhibited the highest rate of stem growth and accumulated the most stem dry matter, followed by the intermediate cultivar, SH108, while the dwarf cultivar, Df216, displayed the lowest values. Furthermore, SH108 exhibited a higher harvest index, as well as superior pod and kernel yields compared to both HY33 and Df216. Transcriptome and metabolome analyses identified differentially expressed genes (DEGs) and differentially expressed metabolites (DEMs) associated with phenylpropanoid and flavonoid biosynthesis. Notably, downregulated DEGs in Df216/HY33 and Df216/SH108 included phenylalanine ammonia-lyase (PAL), caffeoyl-CoA O-methyltransferase (COMT), and ferulate-5-hydroxylase (F5H), while downregulated DEMs included p-coumaryl alcohol, chlorogenic acid, and L-epicatechin. Compared to HY33, the reduced activities of PAL, COMT, and F5H resulted in a decreased stem lignin content in Df216. Additionally, downregulated DEGs involved in gibberellin (GA) and brassinosteroid (BR) biosynthesis were identified in Df216/HY33, which contributed to the lowest levels of GA1, GA3, and BR contents in Df216. The results suggest that the dwarf phenotype arises from impaired GA and BR biosynthesis and signaling, resulting in a slower stem growth rate and reduced lignin accumulation.

POTENTIAL APPLICATIONS OF LIGNIN AND ITS DERIVATIVES FROM LIGNOCELLULOSIC BIOMASS – A REVIEW

Lignin is the second most abundant component of lignocellulose biomass after cellulose with annual production of 70 million tons. Lignin constitutes between 15 to 40 percent of its dry weight, with varying composition in woody plants such as softwood (18-25%) and hardwood (27-33%), and non-woody plant such as grass (17-24%). The polyphenolic polymer is made up of three monolignols such as coniferyl alcohol, sinapyl alcohol, and p-coumaryl alcohol that later forms an aromatic structure consisting of guaiacyl, syringyl, and p-hydroxyphenyl. The highly branched three-dimensional structure is both complex and recalcitrant, hence making its utilization difficult. However, the polymeric lignin can be extracted by various methods such as physical, chemical and biological. The extracted lignin has high potential to be converted into monomeric aromatic derivatives that could serve as a building block for chemical synthesis, biomaterials, bio-oils, wastewater treatment and food industry. The conversion involves several methods such as alkaline nitrobenzene, pyrolysis, catalytic technology, combustion, gasification, hydrocracking and oxidation.

Integrated metabolome, transcriptome analysis, and multi-flux full-length sequencing offer novel insights into the function of lignin biosynthesis as a Sesuvium portulacastrum response to salt stress

Sesuvium portulacastrum is a typical halophyte. However, few studies have investigated its salt-tolerant molecular mechanism. In this study, metabolome, transcriptome, and multi-flux full-length sequencing analysis were conducted to investigate the significantly different metabolites (SDMs) and differentially expressed genes (DEGs) of S. portulacastrum samples under salinity. The complete-length transcriptome of S. portulacastrum was developed, which contained 39,659 non-redundant unigenes. RNA-seq results showed that 52 DEGs involved in lignin biosynthesis may be responsible for S. portulacastrum salt tolerance. Furthermore, 130 SDMs were identified, and the salt response could be attributed to the p-coumaryl alcohol-rich in lignin biosynthesis. The co-expression network that was constructed after comparing the different salt treatment processes showed that the p-Coumaryl alcohol was linked to 30 DEGs. Herein, 8 structures genes, i.e., Sp4CL, SpCAD, SpCCR, SpCOMT, SpF5H, SpCYP73A, SpCCoAOMT, and SpC3′H were identified as significant factors in regulating lignin biosynthesis. Further investigation revealed that 64 putative transcription factors (TFs) may interact with the promoters of the above-mentioned genes. Together, the data revealed a potential regulatory network comprising important genes, putative TFs, and metabolites involved in the lignin biosynthesis of S. portulacastrum roots under salt stress, which could serve as a rich useful genetic resource for breeding excellent salt-tolerant plants.

A novel perspective to investigate how nanoselenium and melatonin lengthen the cut carnation vase shelf

Nano-selenium (nano-Se) and melatonin (MT) applications confirmed to boost plant growth and resistance. The mechanism of various ratios of nano-Se and MT foliar application postpone the senescence of fresh cut carnation flowers and improve vase life remains unclear. In this study, a combined effect with nano-Se (nano-Se5, 5 mg/L) and MT(MT1, 1 mg/L) was preferable to the control, nano-Se, and MT treatment alone when it came to delaying flower senescence. They enhance the antioxidant ability of carnation flowers by lowering MDA and H2O2 levels, raising SOD and POD concentrations, and lowering procyanidins biosynthesis (catechins and epicatechin). Inducing the biosynthesis of hormonal compounds (salicylic acid, jasmonic acid, and abscisic acid), their combination also boosted the growth of carnations. Biofortification with nano-Se and MT substantially increased the amounts of key lignin biosynthesis pathway metabolites (L-phenylalanine, p-hydroxycinnamic acid, p-coumaric acid, perillyl alcohol, p-Coumaryl alcohol, and cinnamic acid), which may increase stem cellular thickness and facilitate water absorption and transmission. The study hypothesizes that nano-Se and MT synergistic applications act as a new efficient non-toxic preservative to extend the vase life and improve the decorative value of carnations.

Comparative Multi-Omics Analysis Reveals Lignin Accumulation Affects Peanut Pod Size.

Pod size is one of the important factors affecting peanut yield. However, the metabolites relating to pod size and their biosynthesis regulatory mechanisms are still unclear. In the present study, two peanut varieties (Tif and Lps) with contrasting pod sizes were used for a comparative metabolome and transcriptome analysis. Developing peanut pods were sampled at 10, 20 and 30 days after pegging (DAP). A total of 720 metabolites were detected, most of which were lipids (20.3%), followed by phenolic acids (17.8%). There were 43, 64 and 99 metabolites identified as differentially accumulated metabolites (DAMs) at 10, 20 and 30 DAP, respectively, and flavonoids were the major DAMs between Tif and Lps at all three growth stages. Multi-omics analysis revealed that DAMs and DEGs (differentially expressed genes) were significantly enriched in the phenylpropanoid biosynthesis (ko00940) pathway, the main pathway of lignin biosynthesis, in each comparison group. The comparisons of the metabolites in the phenylpropanoid biosynthesis pathway accumulating in Tif and Lps at different growth stages revealed that the accumulation of p-coumaryl alcohol (H-monolignol) in Tif was significantly greater than that in Lps at 30 DAP. The differential expression of gene-LOC112771695, which is highly correlated with p-coumaryl alcohol and involved in the biosynthesis of monolignols, between Tif and Lps might explain the differential accumulation of p-coumaryl alcohol. The content of H-lignin in genetically diverse peanut varieties demonstrated that H-lignin content affected peanut pod size. Our findings would provide insights into the metabolic factors influencing peanut pod size and guidance for the genetic improvement of the peanut.

UV-C irradiation accelerated the deposition of suberin and lignin at wounds by activating phenylpropanoid metabolism in potato tubers

UV-C could directly inactivate pathogens, and reduce postharvest diseases of fruits and vegetables by inducing resistance. To date, no studies have been carried out to verify whether UV-C may accelerate the wound healing of potato tubers. The present results demonstrated that UV-C irradiation up-regulated StPAL, St4CL, and StCAD expression and activated phenylalanine ammonia-lyase (PAL), 4-coumarate: coenzyme A ligase (4CL), and cinnamyl alcohol dehydrogenase (CAD). Meanwhile, UV-C irradiation elevated the levels of four phenolic acids (p-coumaric acid, caffeic acid, sinapic acid, and ferulic acid) and three lignin monomers (coniferyl alcohol, sinapyl alcohol, and p-coumaryl alcohol), and accelerated the suberin polyphenolic (SPP) and lignin accumulation at wounds, thereby decreasing weight loss and disease index. The weight loss and disease index in the UV-C irradiated tubers were 36.48% and 56.25% lower than that of the control on the 14 d of healing, respectively. Taken together, UV-C irradiation promoted the process of wound healing in potato tubers by stimulating phenylpropanoid metabolism as well as accelerating the SPP and lignin accumulation at wounds. Therefore, UV-C irradiation could be employed as a simple, safe, and low-cost handling technology for accelerating wound healing of potato tubers.

Extraction, quantification and characterization of lignin extracted from bamboo biomass

Lignin, a heterogeneous polymer that presents about 20–30% in lignocellulose emerged as a promising feedstock for the production of specialty chemicals. After cellulose, Lignin is the second most abundant natural polymer. Lignin is a three-dimensional, highly cross-linked macromolecule composed of three types of substituted phenols, which include coniferyl, sinapyl, and p-coumaryl alcohols having a vast number of functional groups and linkages. The properties of lignin are dependent upon the type of extraction method used. This work-study was carried out focusing on the properties of lignin extracted from bamboo (Bambusa Polymorpha) using acid treatment, alkali treatment and sequential organosolv treatment. Isolated lignins were characterized by Fourier transform infrared spectroscopy (FTIR), UV analysis, Thermogravimetric analysis (TGA) to compare thermal and chemical composition. It was found that lignin obtained from organosolv method provided the greatest yield of the various extraction methods. FTIR spectral studies showed the characteristics peaks of lignin and it was found that the bamboo lignin is unique and it is HGS type lignin. The type of extraction method used was seen to affect the thermal properties. It was found that lignin extracted from acid treatment has the greatest thermal stability and purity.