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1.
Plant Sci ; 286: 7-16, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31300144

RESUMO

Cotton fibers are developed epidermal cells of the seed coat and contain large amounts of cellulose and minor lignin-like components. Lignin in the cell walls of cotton fibers effectively provides mechanical strength and is also presumed to restrict fiber elongation and secondary cell wall synthesis. To analyze the effect of lignin and lignin-like phenolics on fiber quality and the transcriptional regulation of lignin synthesis in cotton fibers, we characterized the function of a bHLH transcription factor, GhbHLH18, during fiber elongation stage. GhbHLH18 knock-down plants have longer and stronger fibers, and accumulate less lignin-like phenolics in mature cotton fibers than control plants. By mining public transcriptomic data for developing fibers, we discovered that GhbHLH18 is coexpressed with most lignin synthesis pathway genes. Furthermore, we showed that GhbHLH18 strongly binds to the E-box in the promoter region of GhPER8 and activates its expression. Transient over expression of GhPER8 protein in tobacco leaves significantly decreased the content of coniferyl alcohol and sinapic alcohol-the substrate respectively for G-lignin and S-lignin biosynthesis. These results suggest that GhbHLH18 is negatively associated with fiber quality by activating peroxidase-mediated lignin metabolism, thus the paper represents an alternative strategy to improve fiber quality.


Assuntos
Fibra de Algodão/análise , Gossypium/genética , Lignina/biossíntese , Proteínas de Plantas/genética , Fatores de Transcrição/genética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Gossypium/metabolismo , Proteínas de Plantas/metabolismo , Fatores de Transcrição/metabolismo
2.
Phytochemistry ; 166: 112063, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31280091

RESUMO

Chlorogenic acids (CGAs) and the biopolymer lignin are both products of the phenylpropanoid pathway. Whereas CGAs have been reported to play a role during stress responses, lignin is a major component of secondary cell walls, providing physical strength and hydrophobicity to supportive and water-conducting tissues. Because the chemical structure of CGAs largely resembles those of some lignin intermediates and because CGAs can be converted back to hydroxycinnamoyl-CoAs in vitro, CGAs have been considered authentic intermediates of the lignin biosynthetic pathway. However, it is still unclear whether and how the CGA pool can be channeled towards the production of lignin monomers in response to developmental or environmental signals. Comprehensive studies on the catalytic activity of recombinant enzymes together with functional characterizations in planta have been very useful in understanding the potential interdependence between these two metabolic routes. Here we present the current understanding on CGA metabolism and discuss the biochemical and molecular evidence of the metabolic re-routing of CGAs towards lignin.


Assuntos
Ácido Clorogênico/metabolismo , Lignina/biossíntese , Esterases/metabolismo
3.
BMC Bioinformatics ; 20(1): 357, 2019 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-31248364

RESUMO

BACKGROUND: C4 photosynthesis is a key domain of plant research with outcomes ranging from crop quality improvement, biofuel production and efficient use of water and nutrients. A metabolic network model of C4 "lab organism" Setaria viridis with extensive gene-reaction associations can accelerate target identification for desired metabolic manipulations and thereafter in vivo validation. Moreover, metabolic reconstructions have also been shown to be a significant tool to investigate fundamental metabolic traits. RESULTS: A mass and charge balance genome-scale metabolic model of Setaria viridis was constructed, which was tested to be able to produce all major biomass components in phototrophic and heterotrophic conditions. Our model predicted an important role of the utilization of NH[Formula: see text] and NO[Formula: see text] ratio in balancing charges in plants. A multi-tissue extension of the model representing C4 photosynthesis was able to utilize NADP-ME subtype of C4 carbon fixation for the production of lignocellulosic biomass in stem, providing a tool for identifying gene associations for cellulose, hemi-cellulose and lignin biosynthesis that could be potential target for improved lignocellulosic biomass production. Besides metabolic engineering, our modeling results uncovered a previously unrecognized role of the 3-PGA/triosephosphate shuttle in proton balancing. CONCLUSIONS: A mass and charge balance model of Setaria viridis, a model C4 plant, provides the possibility of system-level investigation to identify metabolic characteristics based on stoichiometric constraints. This study demonstrated the use of metabolic modeling in identifying genes associated with the synthesis of particular biomass components, and elucidating new role of previously known metabolic processes.


Assuntos
Prótons , Setaria (Planta)/metabolismo , Biomassa , Celulose/biossíntese , Genoma de Planta , Lignina/biossíntese , Redes e Vias Metabólicas , Modelos Biológicos , Fotossíntese , Polissacarídeos/biossíntese , Setaria (Planta)/genética
4.
Plant Dis ; 103(9): 2277-2287, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31215851

RESUMO

To increase phenylpropanoid constituents and energy content in the versatile C4 grass sorghum (Sorghum bicolor [L.] Moench), sorghum genes for proteins related to monolignol biosynthesis were overexpressed: SbMyb60 (transcriptional activator), SbPAL (phenylalanine ammonia lyase), SbCCoAOMT (caffeoyl coenzyme A [CoA] 3-O-methyltransferase), Bmr2 (4-coumarate:CoA ligase), and SbC3H (coumaroyl shikimate 3-hydroxylase). Overexpression lines were evaluated for responses to stalk pathogens under greenhouse and field conditions. Greenhouse-grown plants were inoculated with Fusarium thapsinum (Fusarium stalk rot) and Macrophomina phaseolina (charcoal rot), which cause yield-reducing diseases. F. thapsinum-inoculated overexpression plants had mean lesion lengths not significantly different than wild-type, except for significantly smaller lesions on two of three SbMyb60 and one of two SbCCoAOMT lines. M. phaseolina-inoculated overexpression lines had lesions not significantly different from wild-type except one SbPAL line (of two lines studied) with mean lesion lengths significantly larger. Field-grown SbMyb60 and SbCCoAOMT overexpression plants were inoculated with F. thapsinum. Mean lesions of SbMyb60 lines were similar to wild-type, but one SbCCoAOMT had larger lesions, whereas the other line was not significantly different than wild-type. Because overexpression of SbMyb60, Bmr2, or SbC3H may not render sorghum more susceptible to stalk rots, these lines may provide sources for development of sorghum with increased phenylpropanoid concentrations.


Assuntos
Ascomicetos , Fusarium , Regulação da Expressão Gênica de Plantas , Lignina , Sorghum , Ascomicetos/fisiologia , Fusarium/fisiologia , Genes de Plantas/genética , Lignina/biossíntese , Lignina/genética , Sorghum/genética , Sorghum/microbiologia
5.
Nat Commun ; 10(1): 1994, 2019 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-31040279

RESUMO

Lignin biosynthesis is evolutionarily conserved among higher plants and features a critical 3-hydroxylation reaction involving phenolic esters. However, increasing evidence questions the involvement of a single pathway to lignin formation in vascular plants. Here we describe an enzyme catalyzing the direct 3-hydroxylation of 4-coumarate to caffeate in lignin biosynthesis as a bifunctional peroxidase that oxidizes both ascorbate and 4-coumarate at comparable rates. A combination of biochemical and genetic evidence in the model plants Brachypodium distachyon and Arabidopsis thaliana supports a role for this coumarate 3-hydroxylase (C3H) in the early steps of lignin biosynthesis. The subsequent efficient O-methylation of caffeate to ferulate in grasses is substantiated by in vivo biochemical assays. Our results identify C3H as the only non-membrane bound hydroxylase in the lignin pathway and revise the currently accepted models of lignin biosynthesis, suggesting new gene targets to improve forage and bioenergy crops.


Assuntos
Citosol/enzimologia , Lignina/biossíntese , Arabidopsis/metabolismo , Ascorbato Peroxidases , Brachypodium/metabolismo , Ácidos Cafeicos/metabolismo , Ácidos Cumáricos/metabolismo , Oxigenases de Função Mista/genética , Oxigenases de Função Mista/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo
6.
BMC Plant Biol ; 19(1): 181, 2019 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-31060493

RESUMO

BACKGROUND: Castor (Ricinus communis L.) is an important seed oil crop. Castor oil is a highly demanded oil for several industrial uses. Current castor bean varieties suffer from low productivity and high risk of insect pests and diseases. High productive and pest/disease resistance varieties are needed. Lignin has been associated to the resistance for pest, disease and lodging. Lignin is produced from several metabolites of the phenylpropanoid pathway. PAL is the key enzyme of the phenylpropanoid pathway. The gene PAL may assist in the improvement of resistance of castor bean. RESULTS: The RcPAL CDs was amplified and its function was examined by transgenic overexpression and antisense expression, lignin histochemical staining, real-time PCR, lignin content measurement and morphological investigation. Its full length was 2145 bp, encoding 714 amino acids. The overexpression of RcPAL (7.2 times) increased significantly the PAL activity, dyeing depth of xylem cells and lignin content (14.44%), resulting in a significantly lower plant height, deeper and thicker blade, more green leaves, shorter internode, thicker stem diameter, and opposite in antisense expression plants (lignin content lowered by 27.1%), demonstrated that the gene RcPAL was a key gene in castor lignin biosynthesis. CONCLUSIONS: The gene RcPAL is a key gene in castor lignin biosynthesis and can be induced to express under mechanical damage stress. When up-regulated, it increased the lignin content significantly and dwarfed the plant height, and opposite when down-regulated. The gene RcPAL may assist in the improvement of resistance and plant type of castor bean.


Assuntos
Vias Biossintéticas/genética , Genes de Plantas , Lignina/biossíntese , Fenilalanina Amônia-Liase/genética , Ricinus/genética , Ricinus/metabolismo , Cinamatos/farmacologia , DNA Complementar/genética , Regulação da Expressão Gênica de Plantas , Higromicina B/análogos & derivados , Higromicina B/farmacologia , Fenilalanina Amônia-Liase/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Estresse Mecânico , Transformação Genética
7.
Nat Commun ; 10(1): 2033, 2019 05 02.
Artigo em Inglês | MEDLINE | ID: mdl-31048697

RESUMO

The ratio of syringyl (S) and guaiacyl (G) units in lignin has been regarded as a major factor in determining the maximum monomer yield from lignin depolymerization. This limit arises from the notion that G units are prone to C-C bond formation during lignin biosynthesis, resulting in less ether linkages that generate monomers. This study uses reductive catalytic fractionation (RCF) in flow-through reactors as an analytical tool to depolymerize lignin in poplar with naturally varying S/G ratios, and directly challenges the common conception that the S/G ratio predicts monomer yields. Rather, this work suggests that the plant controls C-O and C-C bond content by regulating monomer transport during lignin biosynthesis. Overall, our results indicate that additional factors beyond the monomeric composition of native lignin are important in developing a fundamental understanding of lignin biosynthesis.


Assuntos
Reatores Biológicos , Lignina/biossíntese , Populus/metabolismo , Catálise , Fracionamento Químico/métodos , Cromatografia Gasosa-Espectrometria de Massas/métodos , Variação Genética , Lignina/química , Espectroscopia de Ressonância Magnética , Fenóis/química , Fenóis/metabolismo , Fenilpropionatos/química , Fenilpropionatos/metabolismo , Populus/genética
8.
J Agric Food Chem ; 67(18): 5204-5211, 2019 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-30998337

RESUMO

Texture attributes such as firmness and lignification are important for fruit quality. Lignification has been widely studied in model plants and energy crops, but fruit lignification has rarely been investigated, despite having an adverse effect on fruit quality and consumer preference. Chilling-induced loquat fruit lignification that occurs after harvest can be alleviated by heat treatment (HT) applied prior to low temperature storage. Enzyme activity assay showed that HT treatment could retard the low temperature-induced increase in cinnamyl alcohol dehydrogenase (CAD) activity. Transcript analysis and substrate activity assays of recombinant CAD proteins highlighted the key role of EjCAD5 in chilling-induced lignin biosynthesis. A novel homeobox-leucine zipper protein ( EjHAT1) was identified as a negative regulator of EjCAD5. Therefore, the effect of HT treatment on lignification may be partially due to the suppression of the EjCAD5 promoter activity by EjHAT1.


Assuntos
Oxirredutases do Álcool/metabolismo , Eriobotrya/enzimologia , Histona Acetiltransferases/metabolismo , Lignina/biossíntese , Proteínas de Plantas/metabolismo , Oxirredutases do Álcool/genética , Temperatura Baixa , Eriobotrya/genética , Eriobotrya/metabolismo , Frutas/enzimologia , Frutas/genética , Frutas/metabolismo , Regulação da Expressão Gênica de Plantas , Histona Acetiltransferases/genética , Temperatura Alta , Proteínas de Plantas/genética , Regiões Promotoras Genéticas
9.
BMC Plant Biol ; 19(1): 97, 2019 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-30866808

RESUMO

BACKGROUND: Regulation of lignin biosynthesis is known to occur at the level of transcription factors (TFs), of which R2R3-MYB family members have been proposed to play a central role via the AC cis-elements. Despite the important roles of TFs in lignin biosynthesis, the post-translational regulation of these TFs, particularly their ubiquitination regulation, has not been thoroughly explored. RESULTS: We describe the discovery of a Populus tomentosa E2 ubiquitin-conjugating enzyme 34 (PtoUBC34), which is involved in the post-translational regulation of transactivation activity of lignin-associated transcriptional repressors PtoMYB221 and PtoMYB156. PtoUBC34 is localized at the endoplasmic reticulum (ER) membrane where it interacts with transcriptional repressors PtoMYB221 and PtoMYB156. This specific interaction allows for the translocation of TFs PtoMYB221 and PtoMYB156 to the ER and reduces their repression activity in a PtoUBC34 abundance-dependent manner. By taking a molecular biology approach with quantitative real-time polymerase chain reaction (qRT-PCR) analysis, we found that PtoUBC34 is expressed in all aboveground tissues of trees in P. tomentosa, and in particular, it is ubiquitous in all distinct differentiation stages across wood formation, including phloem differentiation, cambium maintaining, early and developing xylem differentiation, secondary cell wall thickening, and programmed cell death. Additionally, we discovered that PtoUBC34 is induced by treatment with sodium chloride and heat shock. CONCLUSIONS: Our data suggest a possible mechanism by which lignin biosynthesis is regulated by ER-localized PtoUBC34 in poplar, probably through the ER-associated degradation (ERAD) of lignin-associated repressors PtoMYB221 and PtoMYB156.


Assuntos
Degradação Associada com o Retículo Endoplasmático , Lignina/biossíntese , Populus/genética , Fatores de Transcrição/metabolismo , Enzimas de Conjugação de Ubiquitina/metabolismo , Parede Celular/metabolismo , Retículo Endoplasmático/metabolismo , Regulação da Expressão Gênica de Plantas , Floema/genética , Floema/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Populus/metabolismo , Fatores de Transcrição/genética , Enzimas de Conjugação de Ubiquitina/genética , Madeira/genética , Madeira/metabolismo , Xilema/genética , Xilema/metabolismo
10.
Plant Mol Biol ; 100(1-2): 151-161, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30840202

RESUMO

KEY MESSAGE: Rice leucine-rich repeat extensin-like protein OsPEX1 mediates the intersection of lignin deposition and plant growth. Lignin, a major structural component of secondary cell wall, is essential for normal plant growth and development. However, the molecular and genetic regulation of lignin biosynthesis is not fully understood in rice. Here we report the identification and characterization of a rice semi-dominant dwarf mutant (pex1) with stiff culm. Molecular and genetic analyses revealed that the pex1 phenotype was caused by ectopic expression of a leucine-rich repeat extension-like gene, OsPEX1. Interestingly, the pex1 mutant showed significantly higher lignin content and increased expression levels of lignin-related genes compared with wild type plants. Conversely, OsPEX1-suppresssed transgenics displayed low lignin content and reduced transcriptional abundance of genes associated with lignin biosynthesis, indicating that the OsPEX1 mediates lignin biosynthesis and/or deposition in rice. When OsPEX1 was ectopically expressed in rice cultivars with tall stature that lacks the allele of semi-dwarf 1, well-known green revolution gene, the resulting transgenic plants displayed reduced height and enhanced lodging resistance. Our study uncovers a causative effect between the expression of OsPEX1 and lignin deposition. Lastly, we demonstrated that modulating OsPEX1 expression could provide a tool for improving rice lodging resistance.


Assuntos
Glicoproteínas/metabolismo , Lignina/biossíntese , Oryza/metabolismo , Desenvolvimento Vegetal , Proteínas de Plantas/metabolismo , Sequência de Bases , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Glicoproteínas/genética , Mutação/genética , Oryza/genética , Oryza/fisiologia , Fenótipo , Proteínas de Plantas/genética , Caules de Planta/metabolismo , Plantas Geneticamente Modificadas
11.
Int J Mol Sci ; 20(6)2019 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-30875738

RESUMO

The physiological and molecular basis of seed size formation is complex, and the development of seed coat (derived from integument cells) might be a critical factor that determines seed size formation for many endospermic seeds. Castor bean (Ricinus communis L.), a model system of studying seed biology, has large and persistent endosperm with a hard seed coat at maturity. Here, we investigated the potential molecular mechanisms underlying seed size formation in castor bean by comparing the difference between global gene expression within developing seed coat tissues between the large-seed ZB107 and small-seed ZB306. First, we observed the cell size of seed coat and concluded that the large seed coat area of ZB107 resulted from more cell numbers (rather than cell size). Furthermore, we found that the lignin proportion of seed coat was higher in ZB306. An investigation into global gene expression of developing seed coat tissues revealed that 815 genes were up-regulated and 813 were down-regulated in ZB306 relative to ZB107. Interestingly, we found that many genes involved in regulating cell division were up-regulated in ZB107, whereas many genes involved in regulating lignin biosynthesis (including several NAC members, as well as MYB46/83 and MYB58/63) and in mediating programmed cell death (such as CysEP1 and ßVPE) were up-regulated in ZB306. Furthermore, the expression patterns of the genes mentioned above indicated that the lignification of seed coat tissues was enhanced and occurred earlier in the developing seeds of ZB306. Taken together, we tentatively proposed a potential scenario for explaining the molecular mechanisms of seed coat governing seed size formation in castor bean by increasing the cell number and delaying the onset of lignification in seed coat tissues in large-seed ZB107. This study not only presents new information for possible modulation of seed coat related genes to improve castor seed yield, but also provides new insights into understanding the molecular basis of seed size formation in endospermic seeds with hard seed coat.


Assuntos
Semente de Rícino/anatomia & histologia , Perfilação da Expressão Gênica/métodos , Redes Reguladoras de Genes , Sementes/anatomia & histologia , Semente de Rícino/genética , Semente de Rícino/metabolismo , Regulação da Expressão Gênica de Plantas , Ontologia Genética , Sequenciamento de Nucleotídeos em Larga Escala , Lignina/biossíntese , Filogenia , Proteínas de Plantas/genética , Sementes/genética , Sementes/metabolismo , Análise de Sequência de DNA
12.
Int J Mol Sci ; 20(3)2019 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-30691178

RESUMO

Tartary buckwheat (Fagopyrum tataricum) is considered a profitable crop that possesses medicinal properties, because of its flavonoid compounds. However, the dehulling issue is becoming the bottleneck for consumption of Tartary buckwheat seed. In this study, we investigated the relation between dehulling efficiency and content of lignin and cellulose in the seed hull. Moreover, the untargeted metabolomics analysis, including partial least squares discriminant analysis (PLS-DA) and principal component analysis (PCA), were performed to examine the pattern of metabolic changes in the hull of Tartary buckwheat seeds, XQ 1 and MQ 1, during seed development using gas chromatography mass spectrometry (GC-MS). In mature seed hull the accumulation of highest lignin and lowest cellulose were observed in the hull of MQ 1 seed, a dehulling-friendly variety with highest dehulling efficiency (93%), than that in other dehulling recalcitrant varieties, such as XQ 1 with a range of dehulling efficiency from 2% to 6%. During seed development, the total content of lignin and cellulose increased. MQ 1 and XQ 1 displayed a similar trend in the change of lignin and cellulose that the content was decreased in lignin and increased in cellulose. PCA result showed the metabolic differentiations between MQ 1 and XQ 1 during seed development. The results of our study suggest the compensatory regulation of lignin and cellulose deposition in the hull of mature and developing seed, and deviation of MQ 1 from the ratio of lignin to cellulose of other dehulling recalcitrant varieties may have been a contributing factor that resulted in the dehulling differentia.


Assuntos
Celulose/biossíntese , Fagopyrum/crescimento & desenvolvimento , Lignina/biossíntese , Fagopyrum/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Análise dos Mínimos Quadrados , Análise de Componente Principal , Sementes/crescimento & desenvolvimento , Sementes/metabolismo
13.
J Agric Food Chem ; 67(8): 2139-2147, 2019 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-30668903

RESUMO

p-Quinone methides are involved in lignin biosynthesis as transient intermediates, and the aromatization step has a great impact on the chemical structure of the resulting lignin. A series of quinone methides (QMs) were synthesized and allowed to react with water in pH 3-7 buffers at 25 °C to mimic the formation of p-hydroxyphenyl- and guaiacyl-type (H- and G-type, respectively) ß- O-4 structures in gymnosperm-plant cell walls. Water addition occurred in 3-methoxy-substituted QMs (G-type QMs) with half-lives of 1.4-15 min. In contrast, nonsubstituted QMs (H-type QMs) were very labile; they were aromatized to ß- O-4 products with half-lives of only 10-40 s. The rapid aromatization in H-type QMs may provide an advantage over G-type species for efficiently driving the lignin-polymerization cycle, which possibly contributes to the development of highly lignified compression wood. In the water-addition reaction, the threo isomers of the ß- O-4 products were stereopreferentially formed more than the erythro isomers from both G- and H-type QMs ( erythro/ threo ratios of 24:76 and 50:50, respectively). The proportion of erythro isomers was higher at lower-pH conditions. This pH-dependent trend agrees with findings from a previous study on 3,5-dimethoxy-substituted (syringyl-type, S-type) QMs; thus, this pH-dependent trend is common in H-, G-, and S-type lignin-related QMs. Higher threo-selectivity was obtained by changing the ß-etherified aromatic rings from G- to H-type. A similar but weaker effect was also observed by changing the QM moiety from G- to H-type.


Assuntos
Indolquinonas/química , Lignina/química , Concentração de Íons de Hidrogênio , Indolquinonas/metabolismo , Isomerismo , Lignina/biossíntese , Água/química
14.
Bioresour Technol ; 275: 19-26, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30572259

RESUMO

Pretreating lignocellulosic biomass by phosphoric acid plus hydrogen peroxide (PHP) was integrated with recovering concentrated phosphoric acid (CPA), lignin, and treating phosphorus (P) wastewater. Results indicated no significant effects on cellulose recovery was observed by promoting ethanol addition, but CPA and lignin recovery were improved to 80.0% and 23.3%, respectively. Increasing water addition did not greatly affect CPA recovery (80.0-80.4%), and lignin recovery (22.8-23.6%). Consequently, the ratio of 11:1 (ethanol/PHP solution) and 4:1 (water/de-ethanol liquor) were suggested for solid/liquid separation and lignin precipitation. Average 86.0% CPA was recycled for pretreatment (≥11 runs) with average 96.3% cellulose-glucose conversion. A specially-developed biochar from crab shell was efficient on P removal with maximal adsorption capacity of 261.6 mg/g. Pretreating 1.0 kg wheat straw by 1.1 kg CPA harvested 155.0 g ethanol, 45.0 g high purity lignin and 4.9 kg P-rich biochar fertilizer. Recovering CPA, biochar-fertilizer and lignin, and P wastewater treatment made PHP pretreatment towards more sustainable and cleaner.


Assuntos
Peróxido de Hidrogênio/química , Lignina/biossíntese , Ácidos Fosfóricos/química , Biomassa , Etanol/metabolismo , Glucose/biossíntese , Hidrólise , Reciclagem , Solventes , Triticum/metabolismo
15.
Plant Physiol Biochem ; 135: 215-223, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30576980

RESUMO

Plants respond to the loss of vertical growth re-orientating their affected organs. In trees, this phenomenon has received the scientific attention due to its importance for the forestry industry. Nowadays it is accepted that auxin distribution is involved in the modulation of the tilting response, but how this distribution is controlled is not fully clear. Auxin transporters that determine the spatio-temporal auxin distribution in radiate pine seedlings exposed to 45° of tilting were identified. Additionally, based on indications for an intimate plant hormone crosstalk in this process, IAA and JA contents were evaluated. The experiments revealed that expression of the auxin transporters was down-regulated in the upper half of the tilted stem, while being induced in the lower half. Moreover, transporter-coding genes were first induced at the apical zone of the stem. IAA was consistently redistributed toward the lower half, which is in accordance with the expression profile of the auxin transporters. In contrast, JA was mainly accumulated in the upper half of tilted stems. Finally, lignin content and monomeric composition were analyzed in both sides of stem and along the time course of tilting. As expected, lignin accumulation was higher at the lower half of stem at longer times of tilting. However, the most marked difference was the accumulation of the H-lignin monomer in the lower half, while the G-lignin unit was more dominant in the upper half. Here, we provide detailed insight in the distribution of IAA and JA, affecting the lignin composition during the tilting response in Pinus radiata seedlings.


Assuntos
Ciclopentanos/metabolismo , Ácidos Indolacéticos/metabolismo , Lignina/biossíntese , Oxilipinas/metabolismo , Pinus/metabolismo , Reguladores de Crescimento de Planta/metabolismo , Caules de Planta/metabolismo , Plântula/metabolismo , Regulação da Expressão Gênica de Plantas , Filogenia , Pinus/genética , Pinus/crescimento & desenvolvimento , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Plântula/crescimento & desenvolvimento , Análise de Sequência de DNA
16.
Plant Physiol Biochem ; 133: 142-148, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30419464

RESUMO

Since lignin greatly affects stem strength, which is an important agronomical trait, understanding the relationship between lodging resistance and lignin synthesis is important in barley breeding and selection processes. The aim of the study was to reveal the connection between physiological aspects of lignin synthesis and genetic background of barley cultivars with different lodging phenotype. Three barley cultivars Astor, Scarlett and Jaran were compared by measuring lignin, cellulose and total soluble phenolics content, phenylalanine ammonia-lyase activity (PAL) and expression of cinnamoyl-CoA reductase (CCR) and cinnamyl-alcohol dehydrogenase (CAD) in three lower internodes at flowering and grain filling stage. To assess their genetic background simple sequence repeats (SSR) markers, connected to lodging resistance and plant height, were analyzed. Compared to lodging susceptible cultivars Scarlett and Jaran, a lodging resistant cultivar Astor revealed different dynamics of lignin synthesis and deposition, showing higher PAL activity and total soluble phenolics content as well as higher expression of CCR and CAD genes in the second internode at grain filling stage. Analysis of SSR markers associated with quantitative trait loci (QTL) for lodging resistance revealed that Astor discriminates from Scarlett and Jaran by marker Bmag337 connected with elongation of the second internode. Lignification process is under a strong influence of genotype and environmental factors which determine lignin synthesis dynamics and deposition of lignin in the cell walls of barley.


Assuntos
Hordeum/metabolismo , Lignina/biossíntese , Proteínas de Plantas/metabolismo , Locos de Características Quantitativas , Hordeum/genética , Lignina/genética , Proteínas de Plantas/genética , Especificidade da Espécie
17.
BMC Plant Biol ; 18(1): 198, 2018 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-30223777

RESUMO

BACKGROUND: Gene activity is largely controlled by transcriptional regulation through the action of transcription factors and other regulators. QsMYB1 is a member of the R2R3-MYB transcription factor family related to secondary growth, and in particular, with the cork development process. In order to identify the putative gene targets of QsMYB1 across the cork oak genome we developed a ChIP-Seq strategy. RESULTS: Results provide direct evidence that QsMY1B targets genes encoding for enzymes involved in the lignin and suberin pathways as well as gene encoding for ABCG transporters and LTPs implicated in the transport of monomeric suberin units across the cellular membrane. These results highlight the role of QsMYB1 as a regulator of lignin and suberin biosynthesis, transport and assembly. CONCLUSION: To our knowledge, this work constitutes the first ChIP-Seq experiment performed in cork oak, a non-model plant species with a long-life cycle, and these results will contribute to deepen the knowledge about the molecular mechanisms of cork formation and differentiation.


Assuntos
Lignina/genética , Lipídeos/genética , Proteínas de Plantas/genética , Quercus/genética , Fatores de Transcrição/genética , Sítios de Ligação , Imunoprecipitação da Cromatina , Enzimas/genética , Enzimas/metabolismo , Regulação da Expressão Gênica de Plantas , Lignina/biossíntese , Proteínas de Plantas/metabolismo , Quercus/metabolismo , Sequências Reguladoras de Ácido Nucleico , Sementes/genética , Fatores de Transcrição/metabolismo
18.
Gene ; 676: 37-46, 2018 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-30201104

RESUMO

Casuarina equisetifolia L. is an important multi-purpose, fast growing and widely planted tree species native to tropical and subtropical coastlines of Australia, Southeast Asia, Malaysia, Melanesia, Polynesia and New Caledonia. It is a nitrogen-fixing tree mainly used for charcoal making, construction poles, landscaping, timber, pulp, firewood, windbreaks, shelterbelts, soil erosion and sand dune stabilization. Casuarina wood is presently used for paper and pulp production. Raw material with reduced lignin is highly preferred to increase the pulp yield. Hence, understanding the molecular regulation of wood formation in this tree species is vital for selecting industrially suitable phenotypes for breeding programs. The lignin biosynthetic pathway has been extensively studied in tree species like Eucalypts, poplars, pines, Picea, Betula and Acacia sp. However, studies on wood formation at molecular level is presently lacking in casuarinas. Hence, in the present study, the transcriptome of the developing secondary tissues of 15 years old Casuarina equiseitfolia subsp. equisetifolia was sequenced, de novo assembled, annotated and mapped to functional pathways. Transcriptome sequencing generated a total of 26,985 transcripts mapped to 31 pathways. Mining of the annotated data identified nine genes involved in lignin biosynthesis pathway and relative expression of the transcripts in four tissues including scale-like leaves, needle-like brachlets, wood and root were documented. The expression of CeCCR1 and CeF5H were found to be significantly high in wood tissues, while maximum expression of CeHCT was documented in stem. Additionally, CeTUBA and CeH2A were identified as the most stable reference transcript for normalization of qRT-PCR data in C. equisetifolia. The present study is the first wood genomic resource in C. equisetifolia, which will be valuable for functional genomics research in this genus.


Assuntos
Lignina/biossíntese , Lignina/genética , Pinus/genética , Sequência de Bases , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica de Plantas/genética , Ontologia Genética , Pinus/metabolismo , Melhoramento Vegetal , Transcriptoma/genética , Árvores/genética , Madeira
19.
Planta ; 248(5): 1063-1078, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30078075

RESUMO

MAIN CONCLUSIONS: The 4-coumarate-CoA ligases (4CL) contribute in channelizing flux of different phenylpropanoid biosynthetic pathways. Expression of 4CL is optimized at developmental stages and in response to environmental triggers such as biotic and abiotic stresses. The enzyme is valuable in metabolic pathway engineering for curcuminoids, resveratrol, biofuel production and nutritional improvement. Vigorous analysis of regulation at functional and expression level is obligatory to attain efficient commercial production of candidate metabolites using 4CL. Phenylpropanoid pathway provides precursors for numerous secondary metabolites in plants. In this pathway, 4-coumarate-CoA ligase (EC 6.2.1.12, 4CL) is the main branch point enzyme which generates activated thioesters. Being the last enzyme of three shared common steps in general phenylpropanoid pathway, it contributes to channelize precursors for different phenylpropanoids. In plants, 4CL enzymes are present in multiple isoforms and encoded by small gene family. It belongs to adenylate-forming enzyme family and catalyzes the reaction that converts hydroxy or methoxy cinnamic acid derivatives to corresponding thioesters. These thioesters are further utilized for biosynthesis of phenylpropanoids, which are known for having numerous nutritional and medicinal applications. In addition, the 4CL enzymes have been characterized from various plants for their role in plant physiology or in biotic and abiotic stresses. Furthermore, specific isoforms are differentially regulated upon exposure to diverse stimuli leading to flux diversion toward the particular metabolite biosynthesis. Evolutionary studies showed that 4CL separately evolved after monocot and dicot segregation. Here, we provide a comprehensive review on 4CL, which includes evolution, function, gene/protein structure, role in metabolite biosynthesis and cellular partition, and their regulation. Based on the available data, we have explored the scope for pathway engineering by utilizing 4CL enzymes.


Assuntos
Coenzima A Ligases/genética , Plantas/enzimologia , Evolução Biológica , Coenzima A Ligases/química , Coenzima A Ligases/metabolismo , Flavonoides/biossíntese , Regulação da Expressão Gênica de Plantas , Genoma de Planta/genética , Lignina/biossíntese , Engenharia Metabólica/métodos , Redes e Vias Metabólicas , Filogenia , Plantas/genética , Plantas/metabolismo
20.
Funct Integr Genomics ; 18(5): 519-531, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29675811

RESUMO

PHD-finger proteins, which belongs to the type of zinc finger family, and that play an important role in the regulation of both transcription and the chromatin state in eukaryotes. Currently, PHD-finger proteins have been well studied in animals, while few studies have been carried out on their function in plants. In the present study, 129 non-redundant PHD-finger genes were identified from 5 Rosaceae species (pear, apple, strawberry, mei, and peach); among them, 31 genes were identified in pear. Subsequently, we carried out a bioinformatics analysis of the PHD-finger genes. Thirty-one PbPHD genes were divided into 7 subfamilies based on the phylogenetic analysis, which are consistent with the intron-exon and conserved motif analyses. In addition, we identified five segmental duplication events, implying that the segmental duplications might be a crucial role in the expansion of the PHD-finger gene family in pear. The microsynteny analysis of five Rosaceae species showed that there were independent duplication events in addition to the genome-wide duplication of the pear genome. Subsequently, ten expressed PHD-finger genes of pear fruit were identified using qRT-PCR, and one of these genes, PbPHD10, was identified as an important candidate gene for the regulation of lignin synthesis. Our research provides useful information for the further analysis of the function of PHD-finger gene family in pear.


Assuntos
Cromatina/química , Frutas/genética , Regulação da Expressão Gênica de Plantas , Dedos de Zinco PHD , Proteínas de Plantas/genética , Pyrus/genética , Cromatina/metabolismo , Biologia Computacional , Frutas/crescimento & desenvolvimento , Frutas/metabolismo , Perfilação da Expressão Gênica , Ontologia Genética , Lignina/biossíntese , Anotação de Sequência Molecular , Família Multigênica , Filogenia , Proteínas de Plantas/metabolismo , Pyrus/classificação , Pyrus/crescimento & desenvolvimento , Pyrus/metabolismo , Duplicações Segmentares Genômicas , Transcriptoma
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