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1.
Genes (Basel) ; 15(3)2024 02 25.
Artigo em Inglês | MEDLINE | ID: mdl-38540353

RESUMO

Lignin is complex, three-dimensional biopolymer existing in plant cell wall. Lignin biosynthesis is increasingly highlighted because it is closely related to the wide applications in agriculture and industry productions, including in pulping process, forage digestibility, bio-fuel, and carbon sequestration. The functions of lignin in planta have also attracted more attentions recently, particularly in plant defense response against different pathogens. In this brief review, the progress in lignin biosynthesis is discussed, and the lignin's roles in disease resistance are thoroughly elucidated. This issue will help in developing broad-spectrum resistant crops in agriculture.


Assuntos
Resistência à Doença , Lignina , Resistência à Doença/genética , Plantas
2.
Plant Physiol ; 191(2): 957-973, 2023 02 12.
Artigo em Inglês | MEDLINE | ID: mdl-36459464

RESUMO

The photosynthetic mechanism of crop yields in fluctuating light environments in the field remains controversial. To further elucidate this mechanism, we conducted field and simulation experiments using maize (Zea mays) plants. Increased planting density enhanced the light fluctuation frequency and reduced the duration of daily high light, as well as the light-saturated photosynthetic rate, biomass, and yield per plant. Further analysis confirmed a highly significant positive correlation between biomass and yield per plant and the duration of photosynthesis related to daily high light. The simulation experiment indicated that the light-saturated photosynthetic rate of maize leaves decreased gradually and considerably when shortening the daily duration of high light. Under an identical duration of high light exposure, increasing the fluctuation frequency decreased the light-saturated photosynthetic rate slightly. Proteomic data also demonstrated that photosynthesis was mainly affected by the duration of high light and not by the light fluctuation frequency. Consequently, the current study proposes that an appropriate duration of daily high light under fluctuating light environments is the key factor for greatly improving photosynthesis. This is a promising mechanism by which the photosynthetic productivity and yield of maize can be enhanced under complex light environments in the field.


Assuntos
Proteômica , Zea mays , Fotossíntese , Biomassa , Folhas de Planta , Luz
3.
Planta ; 253(2): 30, 2021 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-33423087

RESUMO

MAIN CONCLUSION: 46 monocot chimeric jacalins (MCJs) were mined from wheat genome. They were divided into three subfamilies with the activity of mannose-specific lectins and had effects on dehydration tolerance or disease resistance. Monocot chimeric jacalin (MCJ) is a newly identified subfamily of plant lectins that exclusively exists in Poaceae. The MCJs are modular proteins consisting of a dirigent domain and a jacalin-related lectin domain. Their unique evolution and various functions are not fully understood as only few members of MCJ have so for been investigated. From wheat, 46 MCJs were identified and phylogenetically classified into three subfamilies, in which subfamily I represented the early evolutionary cluster. MCJ genes are evenly distributed among three subgenomes of wheat, indicating that MCJ might be an ancient gene in Poaceae. qRT-PCR analysis showed that TaMCJ1 and TaMCJ2 were mainly expressed in leaves while TaMCJ3 in root tissues. All these TaMCJ genes are JA or ABA inducible. All three proteins exhibited agglutinating activity but different preference to mannose-binding. The overexpression of TaMCJ3 in tobacco increased dehydration tolerance, while TaMCJ1 enhanced wildfire disease resistance. The lignin biosynthetic genes were temporarily induced after pathogen inoculation in transgenic tobacco overexpressing TaMCJ, but the specific association with TaMCJ was not established. This evidence argued against the notion that the dirigent domain in TaMCJ is directly linked with lignin metabolism. Taken together, these results pave the way for a better understanding of the manifold functionality of MCJs and offer important insights to the evolutionary history of MCJ.


Assuntos
Genoma de Planta , Lectinas de Plantas , Proteínas de Plantas , Triticum , Resistência à Doença/genética , Genoma de Planta/genética , Lectinas de Plantas/química , Lectinas de Plantas/classificação , Lectinas de Plantas/genética , Lectinas de Plantas/metabolismo , Proteínas de Plantas/genética , Nicotiana/genética , Triticum/genética
4.
Photosynth Res ; 149(1-2): 57-68, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32783175

RESUMO

Plants in their natural environment are often exposed to fluctuating light because of self-shading and cloud movements. As changing frequency is a key characteristic of fluctuating light, we speculated that rapid light fluctuation may induce rapid photosynthetic responses, which may protect leaves against photoinhibition. To test this hypothesis, maize seedlings were grown under fluctuating light with various frequencies (1, 10, and 100 cycles of fluctuations/10 h), and changes in growth, chlorophyll content, gas exchange, chlorophyll a fluorescence, and P700 were analyzed carefully. Our data show that though the growth and light-saturated photosynthetic rate were depressed by rapidly fluctuating light, photosynthesis induction was clearly speeded up. Furthermore, more rapid fluctuation of light strikingly reduced the chlorophyll content, while thermal dissipation was triggered and enhanced. The chlorophyll a fluorescence induction kinetics and P700 absorption results showed that the activities of both photosystem II and photosystem I decreased as the frequency of the fluctuating light increased. In all treatments, the light intensities of the fluctuating light were kept constant. Therefore, rapid light fluctuation frequency itself induced the acceleration of photosynthetic induction and the enhancement of photoprotection in maize seedlings, which play important roles in protecting photosynthetic apparatus against fluctuating high light to a certain extent.


Assuntos
Adaptação Ocular/fisiologia , Adaptação Fisiológica , Fotossíntese/fisiologia , Folhas de Planta/metabolismo , Luz Solar/efeitos adversos , Zea mays/crescimento & desenvolvimento , Zea mays/metabolismo , Produtos Agrícolas/crescimento & desenvolvimento , Produtos Agrícolas/metabolismo , Folhas de Planta/crescimento & desenvolvimento , Estresse Fisiológico
5.
Plant Sci ; 262: 32-38, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28716418

RESUMO

ROP is a subfamily of small GTP-binding proteins that uniquely exist in plants. It acts as versatile molecular switches that regulate various developmental processes. Some ROP proteins are also reported to affect defense responses, although their exact mechanism is not fully understood. Herein, ROP members in wheat were mined; the functions of three wheat ROP proteins were studied. RT-PCR results showed that the expression of TaRac1 was rapidly and strongly induced after leaf rust infection. TaRac1 interacted with TaCCR in yeast-hybridization assay. The overexpression of TaRac1 in tobacco promoted CCR and CAD gene expression, increased the total lignin content and sinapyl lignin proportion, and then enhanced resistance to tobacco black shank and bacterial wilt diseases. In contrast, TaRac3 and TaRac4 did not show to interact with TaCCR. Furthermore, the overexpression of TaRac3 and TaRac4 did not increase lignin gene expression and lignin accumulation either. Unlike TaRac1, the overexpression of TaRac3 increased susceptibility to both black shank and bacterial wilt pathogens, while overexpression of TaRac4 showed no effect on disease resistance but promoted the root growth in tobacco seedling. These data collectively suggest that TaRac1 in Group II is mainly involved in regulating lignin metabolism which, in turn, responsible for the observed roles in pathogen resistance. TaRac3 and TaRac4 have the minor roles in defense response but may act on regulation in plant developmental processes. These results shed light on the complexity and diverse function of ROP in plant defense pathway.


Assuntos
Lignina/metabolismo , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Triticum/metabolismo , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/genética , Nicotiana/genética , Nicotiana/metabolismo , Triticum/genética
6.
Plant Sci ; 238: 105-14, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26259179

RESUMO

SKP1 is a core component of SCF complex, a major type of E3 ubiquitin ligase catalyzing the last step in ubiquitin-mediated protein degradation pathway. In present study, SKP1 gene family in Solanum pimpinellifolium (SSK), a wild species of tomato, was investigated. A total of 19 SSK genes were identified through homologous search. Their chromosomal locations, gene structures, phylogeny, expression profiles, sub-cellular localizations and protein-protein interaction patterns with putative F-box proteins were analyzed in detail. The high homology and similar expression patterns among clustered SSK genes in chromosome suggested that they may have evolved from duplication events and are functionally redundant. Sub-cellular localization indicated that most of the SSK proteins are distributed in both cytosol and nucleus, except for SSK8, which is detected in cytosol only. Tissue-specific expression patterns suggested that many SSK genes may be involved in tomato fruit development. Furthermore, several SSK genes were found to be responsive to heat stress and salicylic acid treatment. Based on phylogenetic analysis, expression profiles and protein interaction property, we proposed that tomato SSK1 and SSK2 might have similar function to ASK1 and ASK2 in Arabidopsis.


Assuntos
Perfilação da Expressão Gênica , Genes de Plantas , Filogenia , Solanum/genética , Arabidopsis/genética , Cromossomos de Plantas/genética , Sequência Conservada/genética , Proteínas F-Box/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Motivos de Nucleotídeos/genética , Especificidade de Órgãos/genética , Oryza/genética , Reguladores de Crescimento de Plantas/farmacologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Ligação Proteica/efeitos dos fármacos , Transporte Proteico/efeitos dos fármacos , Estresse Fisiológico/efeitos dos fármacos , Estresse Fisiológico/genética , Frações Subcelulares/efeitos dos fármacos , Frações Subcelulares/metabolismo , Técnicas do Sistema de Duplo-Híbrido
7.
Planta ; 242(1): 113-22, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25854602

RESUMO

MAIN CONCLUSION: TaCCoAOMT1 is located in wheat chromosome 7A and highly expressed in stem and root. It is important for lignin biosynthesis, and associated with stem maturity but not lodging resistance. Caffeoyl coenzyme A 3-O-methyltransferases (CCoAOMTs) are one important class of enzymes to carry out the transfer of the methyl group from S-adenosylmethionine to the hydroxyl group, and play important roles in lignin and flavonoids biosynthesis. In the present study, sequences for CCoAOMT from the wheat genome were analyzed. One wheat CCoAOMT that belonged to bona fide subclade involved in lignin biosynthesis, namely TaCCoAOMT1, was obtained by the prokaryotic expression in E. coli. The three-dimensional structure prediction showed a highly similar structure of TaCCoAOMT1 with MsCCoAOMT. Recombinant TaCCoAOMT1 protein could only use caffeoyl CoA and 5-hydroxyferuloyl CoA as effective substrates and caffeoyl CoA as the best substrate. TaCCoAOMT1 had a narrow optimal pH and thermal stability. The TaCCoAOMT1 gene was highly expressed in wheat stem and root tissues, paralleled CCoAOMT enzyme activity. TaCCoAOMT1 mRNA abundance and enzyme activity increased linearly with stem maturity, but showed little difference between wheat lodging-resistant (H4546) and lodging-sensitive (C6001) cultivars in elongation, heading and milky stages. These data suggest that TaCCoAOMT1 is an important CCoAOMT for lignin biosynthesis that is critical for stem development, but not directly associated with lodging-resistant trait in wheat.


Assuntos
Metiltransferases/metabolismo , Triticum/enzimologia , Regulação da Expressão Gênica no Desenvolvimento , Regulação Enzimológica da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Concentração de Íons de Hidrogênio , Cinética , Metiltransferases/genética , Filogenia , Caules de Planta/crescimento & desenvolvimento , Proteínas Recombinantes/metabolismo , Especificidade por Substrato , Temperatura , Triticum/genética
8.
Crit Rev Biotechnol ; 34(4): 300-6, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23886351

RESUMO

Monocot chimeric jacalins are a small group of lectins (currently with nine members), each typically consisting of a dirigent domain and a jacalin-related lectin domain. This unique module structure, along with their limited taxonomic distribution and short time window in molecular evolution, makes them a novel family of lectins. Recent studies have shown that these proteins play important roles in plant stress responses and development. Our knowledge of these proteins in functional domain and evolution has also made significant progress.


Assuntos
Lectinas de Plantas , Evolução Molecular , Filogenia , Lectinas de Plantas/química , Lectinas de Plantas/classificação , Lectinas de Plantas/genética , Lectinas de Plantas/fisiologia
9.
Biochimie ; 95(2): 359-65, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23116711

RESUMO

Ta-JA1 is a jacalin-like lectin from wheat (Triticum aestivum) plants. To date, its homologs are only observed in the Gramineae family. Our previous experiments have demonstrated that Ta-JA1 contains a modular structure consisting of an N-terminal dirigent domain and a C-terminal jacalin-related lectin domain (JRL) and this protein exhibits a mannose-specific lectin activity. The over-expression of Ta-JA1 gene provides transgenic plants a broad-spectrum resistance to diseases. Here, we report the differential activities of the dirigent and JRL domains of Ta-JA1. In vitro assay showed that the recombinant JRL domain could effectively agglutinate rabbit erythrocytes and pathogen bacteria Pseudomonas syringe pv tabaci. These hemagglutination activities could be inhibited by mannose but not by galactose. In contrast, the recombinant dirigent domain did not show agglutination activity. Corresponding to these differentiations of activities, similar to full-length of Ta-JA1, the over-expression of JRL domain in transgenic plants also increased resistance to the infection of P. syringe. Unlike JRL, the over-expression of dirigent domain in transgenic plants led to alteration of the seedling sensitivity to salts. In addition, a d(N)/d(S) ratio analysis of Ta-JA1 and its related proteins showed that this protein family functionally limited to a few crop plants, such as maize, rice and wheat.


Assuntos
Lectinas de Plantas/química , Proteínas de Plantas/química , Plantas Geneticamente Modificadas , Triticum/genética , Aglutinação/efeitos dos fármacos , Animais , Ciclopentanos/farmacologia , Eritrócitos/citologia , Eritrócitos/efeitos dos fármacos , Escherichia coli/genética , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Manose/metabolismo , Manose/farmacologia , Oryza/genética , Oryza/imunologia , Oxilipinas/farmacologia , Lectinas de Plantas/genética , Lectinas de Plantas/farmacologia , Proteínas de Plantas/genética , Proteínas de Plantas/farmacologia , Estrutura Terciária de Proteína , Pseudomonas/efeitos dos fármacos , Coelhos , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/farmacologia , Triticum/efeitos dos fármacos , Triticum/imunologia , Zea mays/genética , Zea mays/imunologia
10.
Biochimie ; 93(7): 1179-86, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21536093

RESUMO

The subgroup 4 of R2R3-MYB transcription factors has been proposed as repressors regulating the phenylpropanoid pathway. Here, we report a cDNA encoding a subgroup 4 R2R3-MYB factor from wheat, designated as TaMYB4. A phylogenetic analysis showed that TaMYB4 is in a subclade that is specific to monocot plants. The TaMYB4 gene was highly expressed in stem and root tissues. In vitro binding analysis in yeast cells showed TaMYB4 interacted with OsCAD2 promoter characterized by an AC-II element that has been considered as the MYB-binding site in lignin biosynthetic genes. The overexpression of TaMYB4 in transgenic tobacco led to transcriptional reduction of both cinnamyl alcohol dehydrogenase (CAD) and cinnamoyl-CoA reductase (CCR) genes involved in the lignin biosynthesis. Enzymatic assay showed reduction of CAD and CCR activities in the transgenic tobacco plants that substantially decreased the levels of total lignin but increased it's ratio of S/G. In addition, the total flavonoid content was increased in transgenic tobacco leaves, suggesting that the overexpression of TaMYB4 likely led to a redirection of the metabolic flux from the lignin pathway to the flavonoid pathway. These data suggest that TaMYB4 negatively regulates the lignin biosynthesis in wheat.


Assuntos
Oxirredutases do Álcool/genética , Aldeído Oxirredutases/genética , Lignina/biossíntese , Proteínas de Plantas/genética , Triticum/genética , Oxirredutases do Álcool/metabolismo , Aldeído Oxirredutases/metabolismo , Clonagem Molecular , Flavonoides/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Dados de Sequência Molecular , Filogenia , Folhas de Planta/enzimologia , Folhas de Planta/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/classificação , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Nicotiana/enzimologia , Nicotiana/genética , Nicotiana/metabolismo
11.
J Exp Bot ; 61(10): 2735-44, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20400532

RESUMO

Cinnamyl alcohol dehydrogenase (CAD) catalyses the final step in the biosynthesis of monolignols. In the present study, a cDNA encoding a CAD was isolated from wheat, designated as TaCAD1. A genome-wide data mining in the wheat EST database revealed another 10 CAD-like homologues, namely TaCAD2 to TaCAD11. A phylogenetic analysis showed that TaCAD1 belonged to the bona fide CAD group involved in lignin synthesis. Two other putative CADs from the wheat genome (TaCAD2 and TaCAD4) also belonged to this group and were very close to TaCAD1, but lacked C-terminal domain, suggesting that they are pseudogenes. DNA gel blot analysis for the wheat genome showed two to three copies of CAD related to TaCAD1, but RNA gel blot analysis revealed only single band for TaCAD1, which was highly expressed in stem, with quite low expression in leaf and undetectable expression in root. The predicted three-dimension structure of TaCAD1 resembled that of AtCAD5, but two amino acid substitutions were identified in the substrate binding region. Recombinant TaCAD1 protein used coniferyl aldehyde as the most favoured substrate, also showed high efficiencies toward sinapyl and p-coumaryl aldehydes. TaCAD1 was an enzyme being pH-dependent and temperature-sensitive, and showing a typical random catalysing mechanism. At the milky stage of wheat, TaCAD1 mRNA abundance, protein level and enzyme activity in stem tissues were higher in a lodging-resistant cultivar (H4546) than in lodging-sensitive cultivar (C6001). These properties were correlated to the lignin contents and lodging indices of the two cultivars. These data suggest that TaCAD1 is the predominant CAD in wheat stem for lignin biosynthesis and is critical for lodging resistance.


Assuntos
Oxirredutases do Álcool/metabolismo , Lignina/biossíntese , Triticum/enzimologia , Oxirredutases do Álcool/química , Oxirredutases do Álcool/genética , DNA de Plantas/isolamento & purificação , Perfilação da Expressão Gênica , Regulação Enzimológica da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Genoma de Planta/genética , Concentração de Íons de Hidrogênio , Cinética , Filogenia , Proteínas de Plantas/química , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Caules de Planta/enzimologia , Estrutura Secundária de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Temperatura , Triticum/genética
12.
Biochimie ; 92(2): 187-93, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19958808

RESUMO

Jasmonates are known to induce the transcriptional activation of plant defense genes, which leads to the production of jasmonate-regulated proteins (JRP). We previously cloned and characterized a novel jacalin-like lectin gene (Ta-JA1) from wheat (Triticum aestivum L.), which codes a modular JRP with disease response and jacalin-related lectin (JRL) domains and is present only in the Gramineae family. The function of this protein is still unclear. Phylogenetic analysis indicated that Ta-JA1 and related proteins from cereals grouped together, which diverged from JRL with an additional N-terminal disease response domain. The recombinant Ta-JA1 proteins agglutinated rabbit erythrocytes, and this hemagglutination activity was preferentially inhibited by mannose. The Ta-JA1 protein was able to inhibit E. coli cell growth. Overexpression of Ta-JA1 in transgenic tobacco plants increased their resistance to infection by tobacco bacterial, fungal and viral pathogens. Our results suggest that Ta-JA1 belongs to a mannose-specific lectin, which may confer a basal but broad-spectrum resistance to plant pathogens. Ta-JA1 and its homologues in maize, rice, sorghum and creeping bentgrass may represent a new type of monocot lectin with a modular structure and diversity of physiological functions in biotic and abiotic stress responses.


Assuntos
Ciclopentanos/metabolismo , Imunidade Inata/genética , Oxilipinas/metabolismo , Lectinas de Plantas/genética , Lectinas de Plantas/metabolismo , Triticum/genética , Animais , Proliferação de Células/efeitos dos fármacos , Escherichia coli/citologia , Escherichia coli/efeitos dos fármacos , Expressão Gênica , Manose/metabolismo , Filogenia , Doenças das Plantas/imunologia , Lectinas de Plantas/química , Lectinas de Plantas/farmacologia , Plantas Geneticamente Modificadas , Coelhos , Especificidade por Substrato , Nicotiana/genética , Nicotiana/imunologia
13.
Plant Cell Rep ; 28(11): 1759-65, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19820948

RESUMO

A cytokinin biosynthetic gene encoding isopentenyl transferase (ipt) was cloned with its native promoter from Agrobacterium tumefaciens and introduced into tobacco plants. Indolebutyric acid was applied in rooting medium and morphologically normal transgenic tobacco plants were regenerated. Genetic analysis of self-fertilized progeny showed that a single copy of intact ipt gene had been integrated, and T(2) progeny had become homozygous for the transgene. Stable inheritance of the intact ipt gene in T(2) progeny was verified by Southern hybridization. Northern blot hybridization revealed that the expression of this ipt gene was confined in leaves and stems but undetectable in roots of the transgenic plants. Endogenous cytokinin levels in the leaves and stems of the transgenic tobaccos were two to threefold higher than that of control, but in roots, both the transgenic and control tobaccos had similar cytokinin levels. The elevated cytokinin levels in the transgenic tobacco leaves resulted in delayed leaf senescence in terms of chlorophyll content without affecting the net photosynthetic rate. The root growth and morphology of the plant were not affected in the transgenic tobacco.


Assuntos
Alquil e Aril Transferases/genética , Regulação Enzimológica da Expressão Gênica , Nicotiana/enzimologia , Raízes de Plantas/enzimologia , Caules de Planta/enzimologia , Citocininas/biossíntese , Regulação da Expressão Gênica de Plantas , Fenótipo , Folhas de Planta/enzimologia , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Raízes de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Caules de Planta/genética , Caules de Planta/crescimento & desenvolvimento , Plantas Geneticamente Modificadas , Nicotiana/genética , Nicotiana/crescimento & desenvolvimento
14.
J Exp Bot ; 60(9): 2763-71, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19451187

RESUMO

Stem lodging-resistance is an important phenotype in crop production. In the present study, the expression of the wheat COMT gene (TaCM) was determined in basal second internodes of lodging-resistant (H4564) and lodging-susceptible (C6001) cultivars at stem elongation, heading, and milky endosperm corresponding to Zadoks stages Z37, Z60, and Z75, respectively. The TaCM protein levels were analysed by protein gel blot and COMT enzyme activity was determined during the same stem developmental stages. TaCM mRNA levels were higher in H4546 from elongation to the milky stages and in C6001 the TaCM mRNA levels decreased markedly at the heading and milky stages. The TaCM protein levels and COMT activity were also higher in H4564 than that in C6001 at the heading and milky stages. These results corresponded to a higher lignin content measured by the Klason method and stem strength and a lower lodging index in H4564 than in C6001 at the heading and milky stages. Therefore, the TaCM mRNA levels, protein levels, and enzyme activity in developing wheat stems were associated with stem strength and lodging index in these two wheat cultivars. Southern analysis in a different population suggested that a TaCM locus was located in the distal region of chromosome 3BL, which has less investigated by QTL for lodging-resistant phenotype.


Assuntos
Regulação da Expressão Gênica de Plantas , Metiltransferases/genética , Proteínas de Plantas/genética , Triticum/química , Triticum/enzimologia , Mapeamento Cromossômico , Genótipo , Lignina/metabolismo , Metiltransferases/metabolismo , Proteínas de Plantas/metabolismo , Caules de Planta/química , Caules de Planta/enzimologia , Caules de Planta/genética , Triticum/genética
15.
Crit Rev Biotechnol ; 28(3): 213-32, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18855152

RESUMO

Cytokinins are master regulators of plant growth and development. They are involved in the regulation of many important physiological and metabolic processes. Recent progress in cytokinin research at the molecular level, including identification of related genes and cytokinin receptors, plus elucidation of signal transduction, has greatly increased our understanding of cytokinin actions. Although still in its infant stage, molecular breeding of crops with altered cytokinin metabolism, when combined with the transgenic approach, has shown very promising potential for application to agriculture. In this review we briefly introduce recent progress in cytokinin molecular biology, discuss applications of cytokinin genetic engineering to agriculture, and present implications and future research directions.


Assuntos
Citocininas , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Agricultura/tendências , Biotecnologia/tendências , Citocininas/biossíntese , Citocininas/genética , Citocininas/metabolismo , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Transdução de Sinais/genética , Transdução de Sinais/fisiologia
16.
Biochimie ; 90(3): 515-24, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17976886

RESUMO

Caffeic acid 3-O-methyltransferase (COMT) catalyzes the multi-step methylation reactions of hydroxylated monomeric lignin precursors, and is believed to occupy a pivotal position in the lignin biosynthetic pathway. A cDNA (TaCM) was identified from wheat and it was found to be expressed constitutively in stem, leaf and root tissues. The deduced amino acid sequence of TaCM showed a high degree of identity with COMT from other plants, particularly in SAM binding motif and the residues responsible for catalytic and substrate specificity. The predicted TaCM three-dimensional structure is very similar with a COMT from alfalfa (MsCOMT), and TaCM protein had high immunoreactive activity with MsCOMT antibody. Kinetic analysis indicated that the recombinant TaCM protein exhibited the highest catalyzing efficiency towards caffeoyl aldehyde and 5-hydroxyconiferaldehyde as substrates, suggesting a pathway leads to S lignin via aldehyde precursors. Authority of TaCM encoding a COMT was confirmed by the expression of antisense TaCM gene in transgenic tobacco which specifically down-regulated the COMT enzyme activity. Lignin analysis showed that the reduction in COMT activity resulted in a marginal decrease in lignin content but sharp reduction in the syringl lignin. Furthermore, the TaCM protein exhibited a strong activity towards ester precursors including caffeoyl-CoA and 5-hydroxyferuloyl-CoA. Our results demonstrate that TaCM is a typical COMT involved in lignin biosynthesis. It also supports the notion, in agreement with a structural analysis, that COMT has a broad substrate preference.


Assuntos
Lignina/biossíntese , Metiltransferases/química , Triticum/enzimologia , Sequência de Aminoácidos , DNA Complementar/metabolismo , Genes de Plantas , Cinética , Metiltransferases/genética , Metiltransferases/metabolismo , Modelos Moleculares , Dados de Sequência Molecular , Plantas Geneticamente Modificadas , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Especificidade por Substrato , Nicotiana/enzimologia , Nicotiana/metabolismo
17.
DNA Seq ; 19(2): 130-6, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17852353

RESUMO

The 14-3-3 proteins, originally described as the mammalian brain proteins, are ubiquitous eukaryotic proteins and have been shown to exert an array of function. A great number of 14-3-3 sequences have been reported in Eudicotyledon. The data of 14-3-3 from the monocotyledon plants, however, are limited. In this report, a 14-3-3 cDNA (designated as Ta14A) was isolated from wheat. An extensive search in GenBank database revealed another 14 14-3-3 isoforms from monocotyledonous plants. These proteins plus 14-3-3 isoforms from Arabidopsis were used for phylogenetic reconstruction, which revealed two groups of 14-3-3 proteins in monocotyledonous plants, namely epsilon and non-epsilon, respectively. The epsilon isoforms were present in monocotyledonous plants. Therefore, the gene duplication to result in an epsilon and non-epsilon isoforms was likely to take place before the speciation of monocotyledon and Eudicotyledon plants. Structural analysis indicated that the different conserved domains and structural characters existed in the monocotyledon 14-3-3 isoforms, which will affect their interaction with other effector proteins. Ta14A was strongly expressed in leaf and stem, undetected in root, suggesting it may have the unique functions within these tissues. These data suggest that structure difference and spatial expression of 14-3-3 will be the important factors to confine its functional specificity.


Assuntos
Proteínas 14-3-3/genética , Clonagem Molecular , DNA Complementar/genética , Folhas de Planta/genética , Proteínas de Plantas/genética , Caules de Planta/genética , Triticum/genética , Proteínas 14-3-3/biossíntese , Proteínas 14-3-3/química , Sequência de Aminoácidos , Sequência de Bases , DNA Complementar/química , Evolução Molecular , Dados de Sequência Molecular , Filogenia , Folhas de Planta/química , Proteínas de Plantas/biossíntese , Proteínas de Plantas/química , Caules de Planta/química , Isoformas de Proteínas/biossíntese , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Análise de Sequência de DNA , Análise de Sequência de Proteína , Distribuição Tecidual/genética , Triticum/química
18.
J Exp Bot ; 58(8): 2011-21, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17452751

RESUMO

Cinnamoyl-CoA reductase (CCR) is responsible for the CoA ester to aldehyde conversion in monolignol biosynthesis, which diverts phenylpropanoid-derived metabolites into the biosynthesis of lignin. To gain a better understanding of lignin biosynthesis and its biological function, a cDNA encoding CCR was identified from wheat (Triticum aestivum L.), and designated as Ta-CCR1. Phylogenetic analysis indicated that Ta-CCR1 grouped together with other monocot CCR sequences while it diverged from Ta-CCR2. DNA gel-blot and mapping analyses demonstrated that Ta-CCR1 is present as a single copy gene in the wheat genome. Recombinant Ta-CCR1 protein converted feruloyl CoA, 5-OH-feruloyl CoA, sinapoyl CoA, and caffeoyl CoA, but feruloyl-CoA was the best substrate, suggesting the preferential biosynthesis of G-type lignin. RNA gel-blot analysis indicated that Ta-CCR1 was highly expressed in stem, with lower expression in leaves, and undetectable expression in roots. CCR enzyme activity was increased progressively along with the lignin biosynthesis and stem maturity. During stem development, Ta-CCR1 mRNA levels remained high at elongation, heading, and milky stages in the wheat H4564 cultivar, while they declined dramatically at the heading and milky stages in stems of the C6001 cultivar. Ta-CCR1 mRNA expression paralleled extractable CCR enzyme activity in these two cultivars. Furthermore, high Ta-CCR1 mRNA levels and high CCR enzyme activity in wheat stem were correlated with a higher Klason lignin content and greater stem mechanical strength in the H4564 cultivar. This suggests that Ta-CCR1 and its related CCR enzyme may be involved in the regulation of lignin biosynthesis during stem maturity and then contributes to stem strength support in wheat.


Assuntos
Aldeído Oxirredutases/metabolismo , Proteínas de Plantas/metabolismo , Triticum/enzimologia , Aldeído Oxirredutases/genética , Aldeído Oxirredutases/fisiologia , Mapeamento Cromossômico , Escherichia coli/genética , Dosagem de Genes , Genoma de Planta , Cinética , Lignina/biossíntese , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/fisiologia , Caules de Planta/enzimologia , Caules de Planta/genética , Caules de Planta/crescimento & desenvolvimento , RNA Mensageiro/metabolismo , Análise de Sequência de DNA , Triticum/genética , Triticum/crescimento & desenvolvimento
19.
DNA Seq ; 17(2): 136-42, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17076256

RESUMO

Ran, which functions in nucleocytoplasmic transport and mitosis, binds to and is regulated in part by Ran binding protein (RanBP). A RanBP cDNA (TaRanBP1) was isolated from a wheat cDNA library using RT-PCR product as a probe. The predicted amino acid sequence of TaRanBP1 is over 60% identity to AtRanBP1 from Arabidopsis and also with considerable similarity to human and fungi RanBPs. TaRanBP1 gene was expressed ubiquitously in roots, leaves and stems, with a similar abundance in these tissues. Phylogenetic reconstruction of TaRanBP1 with 32 other RanBPs from 26 species of organisms revealed that RanBPs from plants, animals and fungi clustered as the distinct groups, intraspecies isoforms were not developed for RanBPs, contrast with most other ancestral genes. Structural analysis revealed that all RanBPs were highly conserved in the middle region of their amino acid sequence, which included Ran binding domain and the three conserved motifs that have the essential roles in binding with Ran protein and promotion of GTP hydrolysis by the Ran/RanGAP/RanBP complex. However, N-terminus and C-terminus exhibited very low similarity between the different RanBPs. The different structures in N-terminus and C-terminus of RanBPs are likely to direct the Ran into the specific physiological processes and subsequently exhibit the different roles in different organisms.


Assuntos
Triticum/genética , Proteína ran de Ligação ao GTP/química , Proteína ran de Ligação ao GTP/genética , Motivos de Aminoácidos , Sequência de Aminoácidos , Sequência de Bases , Clonagem Molecular , DNA Complementar , Regulação da Expressão Gênica de Plantas , Biblioteca Gênica , Genes de Plantas , Dados de Sequência Molecular , Filogenia , Proteínas de Plantas/química , Proteínas de Plantas/genética
20.
Biol Chem ; 386(6): 553-60, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16006242

RESUMO

Cinnamoyl-CoA reductase (CCR) is responsible for the CoA ester-->aldehyde conversion in monolignol biosynthesis, which can divert phenylpropanoid-derived metabolites into the biosynthesis of lignin. To gain a better understanding of lignin biosynthesis in wheat (Triticum aestivum L.), a cDNA encoding CCR was isolated and named Ta-CCR2. DNA hybridization analyses demonstrated that the Ta-CCR2 gene exists in three copies in the wheat genome. RNA blot hybridization indicated that Ta-CCR2 was expressed most abundantly in root and stem tissues that were in the process of lignification. The secondary and three-dimensional structures of Ta-CCR2 were analyzed by molecular modeling. Recombinant Ta-CCR2 protein purified from E. coli converted feruloyl CoA, 5-OH-feruloyl CoA, sinapoyl CoA and caffeoyl CoA with almost similar efficiency, suggesting that it is involved in both G and S lignin synthesis. Ta-CCR2 had a very low V max value for 4-coumaroyl CoA, which may serve as a mechanism to control metabolic flux to H lignin in vivo . Furthermore, the reaction mechanism of Ta-CCR2 was analyzed in relation to its possible three-dimensional structure. The activity of Ta-CCR2 in relation to lignin biosynthesis is discussed.


Assuntos
Aldeído Oxirredutases/metabolismo , Triticum/enzimologia , Acil Coenzima A/metabolismo , Aldeído Oxirredutases/química , Aldeído Oxirredutases/genética , Clonagem Molecular , DNA de Plantas/análise , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Biblioteca Gênica , Lignina/metabolismo , Folhas de Planta/enzimologia , Raízes de Plantas/enzimologia , Caules de Planta/enzimologia , Estrutura Secundária de Proteína , RNA Mensageiro/análise , RNA Mensageiro/metabolismo , RNA de Plantas/análise , RNA de Plantas/metabolismo , Triticum/genética
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