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1.
Nat Commun ; 11(1): 6266, 2020 12 08.
Artigo em Inglês | MEDLINE | ID: mdl-33293512

RESUMO

Grain weight (GW) is one of the component traits of wheat yield. Existing reports have shown that multiple phytohormones are involved in the regulation of GW in different crops. However, the potential role of jasmonic acid (JA) remains unclear. Here, we report that triticale grain weight 1 (tgw1) mutant, with marked reductions in both GW and JA content, is caused by a premature stop mutation in keto-acyl thiolase 2B (KAT-2B) involved in ß-oxidation during JA synthesis. KAT-2B overexpression increases GW in wild type and boosts yield. Additionally, KAT-2B compliments the grain defect in tgw1 and rescues the lethal phenotype of the Arabidopsis kat2 mutant in a sucrose-free medium. Despite the suppression of JA synthesis in tgw1 mutant, ABA synthesis is upregulated, which is accompanied by enhanced expression of SAG3 and reduction of chlorophyll content in leaves. Together, these results demonstrate a role of the JA synthetic gene KAT-2B in controlling GW and its potential application value for wheat improvement.

2.
Food Chem ; 303: 125363, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31472383

RESUMO

Present in many plant foods, biogenic phenolic compounds are important bioactive phytonutrients with high anti-oxidant activity and thereby are praised for their health-promoting properties. However, current food nutrient improvement by high phenolic content in staples is limited by the shortage of genetic resources rich in phenolic compounds. To resolve this obstacle, we developed a non-destructive massive analytical approach to screen wheat phenolic mutants. In grains, multiple mutant lines showed significantly higher contents of flavonoids or cell wall-bound phenolic esters. Moreover, five mutants showed higher anti-oxidant potentials in wall-bound phenolic compounds ranging from 15% to 20%, with the maximal close to natural black wheat. In contrast to black wheat, two mutants accumulated higher phenolic compounds in the endosperm. lrf4 was mapped by BSR to a concentrated genomic region in the short arm of chromosome 1A. The present work represents an efficient high-throughput strategy to increase wheat anti-oxidant potential through traditional mutagenesis.


Assuntos
Antioxidantes/metabolismo , Mutação , Fenóis/metabolismo , Triticum/genética , Triticum/metabolismo , Flavonoides/metabolismo
3.
Mol Plant ; 12(12): 1639-1650, 2019 12 02.
Artigo em Inglês | MEDLINE | ID: mdl-31622682

RESUMO

Wheat stripe rust, due to infection by Puccinia striiformis f. sp. tritici (Pst), is a devastating disease that causes significant global grain yield losses. Yr36, which encodes Wheat Kinase START1 (WKS1), is an effective high-temperature adult-plant resistance gene and confers resistance to a broad spectrum of Pst races. We previously showed that WKS1 phosphorylates the thylakoid ascorbate peroxidase protein and reduces its ability to detoxify peroxides, which may contribute to the accumulation of reactive oxygen species (ROS). WKS1-mediated Pst resistance is accompanied by leaf chlorosis in Pst-infected regions, but the underlying mechanisms remain elusive. Here, we show that WKS1 interacts with and phosphorylates PsbO, an extrinsic member of photosystem II (PSII), to reduce photosynthesis, regulate leaf chlorosis, and confer Pst resistance. A point mutation in PsbO-A1 or reduction in its transcript levels by RNA interference resulted in chlorosis and reduced Pst sporulation. Biochemical analyses revealed that WKS1 phosphorylates PsbO at two conserved amino acids involved in physical interactions with PSII and reduces the binding affinity of PsbO with PSII. Presumably, phosphorylated PsbO proteins dissociate from the PSII complex and then undergo rapid degradation by cysteine and aspartic proteases. Taken together, these results demonstrate that perturbations of wheat PsbO by point mutation or phosphorylation by WKS1 reduce the rate of photosynthesis and delay the growth of Pst pathogen before the induction of ROS.


Assuntos
Basidiomycota/fisiologia , Resistência à Doença , Fotossíntese , Complexo de Proteína do Fotossistema II/metabolismo , Doenças das Plantas/imunologia , Proteínas de Plantas/metabolismo , Triticum/microbiologia , Cloroplastos/metabolismo , Fosforilação , Doenças das Plantas/microbiologia , Triticum/citologia , Triticum/imunologia , Triticum/metabolismo
4.
Biochem Biophys Res Commun ; 520(1): 122-127, 2019 11 26.
Artigo em Inglês | MEDLINE | ID: mdl-31582217

RESUMO

A wealth of studies illustrate the powerful antioxidant activities and health-promoting functions of dietary phenolic compounds, e.g., anthocyanins, flavonoids, and phenolic compounds. Ferulate is methylated from caffeoyl CoA using S-adenosyl-L-methionine (SAM) as methyl donor catalyzed by caffeoyl CoA methyltransferase (CCoAOMT). Here we show that Arabidopsis CCoAOMT7 contributes to ferulate content in the stem cell wall. CCoAOMT7 was further shown to bind S-adenosyl-L-homocysteine hydrolase (SAHH), a critical step in SAM synthesis to release feedback suppression on CCoAOMT. CCoAOMT7 also bound S-adenosyl-L-methionine synthases (SAMSs) in vivo, which were mediated by SAHH1. Interruptions of endogenous SAHH1 by artificial miRNA or SAMSs by T-DNA insertion significantly reduced ferulate contents in the stem cell wall. This data reveals a novel protein complex of SAM synthesis cycle associated with O-methyltransferase and provides new insights into cellular methylation processes.


Assuntos
Adenosil-Homocisteinase/metabolismo , Arabidopsis/enzimologia , Metionina Adenosiltransferase/metabolismo , Metiltransferases/metabolismo , Fenol/química , Catálise , Parede Celular/enzimologia , Ácidos Cumáricos/química , Regulação Enzimológica da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Teste de Complementação Genética , Genótipo , Hidrólise , Metilação , Mutação , Plantas Geneticamente Modificadas , Mapeamento de Interação de Proteínas , Técnicas do Sistema de Duplo-Híbrido
5.
BMC Biotechnol ; 17(1): 69, 2017 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-28865427

RESUMO

BACKGROUND: Membrane proteins define biological functions of membranes in cells. Extracellular peptides of transmembrane proteins receive signals from pathogens or environments, and are the major targets of drug developments. Despite of their essential roles, membrane proteins remain elusive in topological studies due to technique difficulties in their expressions and purifications. METHODS: First, the target gene is cloned into a destination vector to fuse with C terminal ubiquitin at the N or C terminus. Then, Cub vector with target gene and NubWT or NubG vectors are transformed into AP4 or AP5 yeast cells, respectively. After mating, the diploid cells are dipped onto selection medium to check the growth. Topology of the target protein is determined according to Table 1. RESULTS: We present a split ubiquitin topology (SUT) analysis system to study the topology and truncation peptide of membrane proteins in a simple yeast experiment. In the SUT system, transcription activator (TA) fused with a nucleo-cytoplasmic protein shows strong auto-activation with both positive and negative control vectors. TA fused with the cytoplasmic end of membrane proteins activates reporter genes only with positive control vector with a wild type N terminal ubiquitin (NubWT). However, TA fused with the extracellular termini of membrane proteins can't activate reporter genes even with NubWT. Interestingly,TA fused with the released peptide of a membrane protein shows autoactivation in the SUT system. CONCLUSION: The SUT system is a simple and fast experimental procedure complementary to computational predictions and large scale proteomic techniques. The preliminary data from SUT are valuable for pathogen recognitions and new drug developments.


Assuntos
Proteínas de Membrana/metabolismo , Proteômica/métodos , Ubiquitina/metabolismo , Vetores Genéticos , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Proteínas de Membrana/genética , Proteínas de Transporte Nucleocitoplasmático/genética , Proteínas de Transporte Nucleocitoplasmático/metabolismo , Peptídeos/metabolismo , Processamento de Proteína , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Ubiquitina/genética
6.
Plant Methods ; 12: 43, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27822293

RESUMO

BACKGROUND: Protein phosphorylation is one of the most important post-translational modifications catalyzed by protein kinases in living organisms. The advance of genome sequencing provided the information of protein kinase families in many organisms, including both model and non-model plants. The development of proteomics technologies also enabled scientists to efficiently reveal a large number of protein phosphorylations of an organism. However, kinases and phosphorylation targets are still to be connected to illustrate the complicated network in life. RESULTS: Here we adapted Pro-Q® Diamond (Pro-Q® Diamond Phosphoprotein Gel Stain), a widely used phosphoprotein gel-staining fluorescence dye, to establish a rapid, economical and non-radioactive fluorescence detection in tube (FDIT) method to analyze phosphorylated proteins. Taking advantages of high sensitivity and specificity of Pro-Q® diamond, the FDIT method is also demonstrated to be rapid and reliable, with a suitable linear range for in vitro protein phosphorylation. A significant and satisfactory protein kinase reaction was detected as fast as 15 min from Wheat Kinase START 1.1 (WKS1.1) on a thylakoid ascorbate peroxidase (tAPX), an established phosphorylation target in our earlier study. CONCLUSION: The FDIT method saves up to 95% of the dye consumed in a gel staining method. The FDIT method is remarkably quick, highly reproducible, unambiguous and capable to be scaled up to dozens of samples. The FDIT method could serve as a simple and sensitive alternative procedure to determine protein kinase reactions with zero radiation exposure, as a supplementation to other widely used radioactive and in-gel assays.

7.
Plant Cell ; 27(6): 1755-70, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25991734

RESUMO

Stripe rust is a devastating fungal disease of wheat caused by Puccinia striiformis f. sp tritici (Pst). The WHEAT KINASE START1 (WKS1) resistance gene has an unusual combination of serine/threonine kinase and START lipid binding domains and confers partial resistance to Pst. Here, we show that wheat (Triticum aestivum) plants transformed with the complete WKS1 (variant WKS1.1) are resistant to Pst, whereas those transformed with an alternative splice variant with a truncated START domain (WKS1.2) are susceptible. WKS1.1 and WKS1.2 preferentially bind to the same lipids (phosphatidic acid and phosphatidylinositol phosphates) but differ in their protein-protein interactions. WKS1.1 is targeted to the chloroplast where it phosphorylates the thylakoid-associated ascorbate peroxidase (tAPX) and reduces its ability to detoxify peroxides. Increased expression of WKS1.1 in transgenic wheat accelerates leaf senescence in the absence of Pst. Based on these results, we propose that the phosphorylation of tAPX by WKS1.1 reduces the ability of the cells to detoxify reactive oxygen species and contributes to cell death. This response takes several days longer than typical hypersensitive cell death responses, thus allowing the limited pathogen growth and restricted sporulation that is characteristic of the WKS1 partial resistance response to Pst.


Assuntos
Ascorbato Peroxidases/fisiologia , Basidiomycota/fisiologia , Doenças das Plantas/microbiologia , Proteínas de Plantas/fisiologia , Espécies Reativas de Oxigênio/metabolismo , Tilacoides/enzimologia , Triticum/microbiologia , Ascorbato Peroxidases/metabolismo , Basidiomycota/patogenicidade , Tilacoides/metabolismo , Triticum/fisiologia
8.
Mol Plant ; 6(6): 1889-903, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23709341

RESUMO

Cutinized and suberized cell walls in plants constitute physiologically important environment interfaces. They act as barriers limiting the loss of water and nutrients and protecting against radiation and invasion of pathogens. The roles of cutin- and suberin polyesters are often attributed to their dominant aliphatic components, but the contribution of aromatic composition to their physiological function remains unclear. By functionally screening a subset of Populus trichocarpa BAHD/HXXXD acyltransferases, we identified a hydroxycinnamoyltransferase that shows specific transacylation activity on ω-hydroxyacids using both feruloyl- and p-coumaroyl- CoA as the acyl donors. We named this enzyme P. trichocarpa hydroxyacid/fatty alcohol hydroxycinnamoyltransferase 1 (PtFHT1). The ectopic expression of the PtFHT1 gene in Arabidopsis increased the incorporation of ferulate in root and seed suberins and in leaf cutin, but not that of p-coumarate, while the aliphatic load in both suberin and cutin polyesters essentially remained unaffected. The overaccumulation of ferulate in lipophilic polyester significantly increased the tolerance of transgenic plants to salt stress treatment; under sub-lethal conditions of salt stress, the ratios of their seed germination and seedling establishment were 50% higher than those of wild-type plants. Our study suggests that, although aromatics are the minor component of polyesters, they play important role in the sealing function of lipidic polymers in planta.


Assuntos
Aciltransferases/metabolismo , Populus/enzimologia , Adaptação Fisiológica , Dados de Sequência Molecular , Filogenia , Folhas de Planta/enzimologia , Proteínas de Plantas/metabolismo , Raízes de Plantas/enzimologia , Populus/classificação , Populus/embriologia , Proteínas Recombinantes/metabolismo , Sementes/enzimologia , Cloreto de Sódio
9.
Mol Plant ; 6(3): 945-58, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23041940

RESUMO

Plant growth requires cell wall extension. The cotton AtRD22-Like 1 gene GhRDL1, predominately expressed in elongating fiber cells, encodes a BURP domain-containing protein. Here, we show that GhRDL1 is localized in cell wall and interacts with GhEXPA1, an α-expansin functioning in wall loosening. Transgenic cotton overexpressing GhRDL1 showed an increase in fiber length and seed mass, and an enlargement of endopleura cells of ovules. Expression of either GhRDL1 or GhEXPA1 alone in Arabidopsis led to a substantial increase in seed size; interestingly, their co-expression resulted in the increased number of siliques, the nearly doubled seed mass, and the enhanced biomass production. Cotton plants overexpressing GhRDL1 and GhEXPA1 proteins produced strikingly more fruits (bolls), leading to up to 40% higher fiber yield per plant without adverse effects on fiber quality and vegetative growth. We demonstrate that engineering cell wall protein partners has a great potential in promoting plant growth and crop yield.


Assuntos
Frutas/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas , Gossypium/crescimento & desenvolvimento , Gossypium/genética , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Parede Celular/metabolismo , Frutas/genética , Gossypium/citologia , Gossypium/metabolismo , Dados de Sequência Molecular , Fenótipo , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Ligação Proteica , Estrutura Terciária de Proteína , Transporte Proteico , Sementes/citologia , Frações Subcelulares/metabolismo
10.
Plant Cell ; 24(1): 50-65, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22247250

RESUMO

Pectin is a major component of the primary cell wall of higher plants. Some galacturonyl residues in the backbone of pectinaceous polysaccharides are often O-acetylated at the C-2 or C-3 position, and the resulting acetylesters change dynamically during the growth and development of plants. The processes involve both enzymatic acetylation and deacetylation. Through genomic sequence analysis, we identified a pectin acetylesterase (PAE1) from black cottonwood (Populus trichocarpa). Recombinant Pt PAE1 exhibited preferential activity in releasing the acetate moiety from sugar beet (Beta vulgaris) and potato (Solanum tuberosum) pectin in vitro. Overexpressing Pt PAE1 in tobacco (Nicotiana tabacum) decreased the level of acetyl esters of pectin but not of xylan. Deacetylation engendered differential changes in the composition and/or structure of cell wall polysaccharides that subsequently impaired the cellular elongation of floral styles and filaments, the germination of pollen grains, and the growth of pollen tubes. Consequently, plants overexpressing PAE1 exhibited severe male sterility. Furthermore, in contrast to the conventional view, PAE1-mediated deacetylation substantially lowered the digestibility of pectin. Our data suggest that pectin acetylesterase functions as an important structural regulator in planta by modulating the precise status of pectin acetylation to affect the remodeling and physiochemical properties of the cell wall's polysaccharides, thereby affecting cell extensibility.


Assuntos
Acetilesterase/metabolismo , Pectinas/metabolismo , Proteínas de Plantas/metabolismo , Pólen/fisiologia , Populus/enzimologia , Populus/metabolismo , Reprodução/fisiologia , Acetilação , Acetilesterase/classificação , Acetilesterase/genética , Dados de Sequência Molecular , Filogenia , Proteínas de Plantas/classificação , Proteínas de Plantas/genética , Populus/fisiologia
11.
Plant Cell ; 23(4): 1512-22, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21487097

RESUMO

Flavonoids are synthesized through an important metabolic pathway that leads to the production of diverse secondary metabolites, including anthocyanins, flavonols, flavones, and proanthocyanidins. Anthocyanins and flavonols are derived from Phe and share common precursors, dihydroflavonols, which are substrates for both flavonol synthase and dihydroflavonol 4-reductase. In the stems of Arabidopsis thaliana, anthocyanins accumulate in an acropetal manner, with the highest level at the junction between rosette and stem. We show here that this accumulation pattern is under the regulation of miR156-targeted SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) genes, which are deeply conserved and known to have important roles in regulating phase change and flowering. Increased miR156 activity promotes accumulation of anthocyanins, whereas reduced miR156 activity results in high levels of flavonols. We further provide evidence that at least one of the miR156 targets, SPL9, negatively regulates anthocyanin accumulation by directly preventing expression of anthocyanin biosynthetic genes through destabilization of a MYB-bHLH-WD40 transcriptional activation complex. Our results reveal a direct link between the transition to flowering and secondary metabolism and provide a potential target for manipulation of anthocyanin and flavonol content in plants.


Assuntos
Antocianinas/biossíntese , Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , MicroRNAs/metabolismo , Transativadores/metabolismo , Oxirredutases do Álcool/genética , Oxirredutases do Álcool/metabolismo , Antocianinas/química , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Cromatografia Líquida , Regulação da Expressão Gênica de Plantas , Genes de Plantas/genética , Espectrometria de Massas , Modelos Biológicos , Complexos Multiproteicos/metabolismo , Plantas Geneticamente Modificadas , Regiões Promotoras Genéticas/genética , Ligação Proteica , Transativadores/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
12.
Proc Natl Acad Sci U S A ; 106(44): 18855-60, 2009 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-19846769

RESUMO

Suberin, a polyester polymer in the cell wall of terrestrial plants, controls the transport of water and nutrients and protects plant from pathogenic infections and environmental stresses. Structurally, suberin consists of aliphatic and aromatic domains; p-hydroxycinnamates, such as ferulate, p-coumarate, and/or sinapate, are the major phenolic constituents of the latter. By analyzing the "wall-bound" phenolics of mutant lines of Arabidopsis deficient in a family of acyl-CoA dependent acyltransferase (BAHD) genes, we discovered that the formation of aromatic suberin in Arabidopsis, primarily in seed and root tissues, depends on a member of the BAHD superfamily of enzymes encoded by At5g41040. This enzyme exhibits an omega-hydroxyacid hydroxycinnamoyltransferase activity with an in vitro kinetic preference for feruloyl-CoA and 16-hydroxypalmitic acid. Knocking down or knocking out the At5g41040 gene in Arabidopsis reduces specifically the quantity of ferulate in suberin, but does not affect the accumulation of p-coumarate or sinapate. The loss of the suberin phenolic differentially affects the aliphatic monomer loads and alters the permeability and sensitivity of seeds and roots to salt stress. This highlights the importance of suberin aromatics in the polymer's function.


Assuntos
Aciltransferases/metabolismo , Proteínas de Arabidopsis/metabolismo , Arabidopsis/enzimologia , Hidrocarbonetos Aromáticos/metabolismo , Lipídeos/biossíntese , Arabidopsis/genética , Biopolímeros/biossíntese , Parede Celular/efeitos dos fármacos , Parede Celular/enzimologia , Ácidos Cumáricos/metabolismo , DNA Bacteriano/genética , Escherichia coli , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Genes de Plantas , Germinação/efeitos dos fármacos , Cinética , Dados de Sequência Molecular , Mutagênese Insercional/efeitos dos fármacos , Mutação/genética , Permeabilidade/efeitos dos fármacos , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/enzimologia , Proteínas Recombinantes/metabolismo , Sementes/efeitos dos fármacos , Sementes/enzimologia , Cloreto de Sódio/farmacologia , Estresse Fisiológico/efeitos dos fármacos
13.
Plant Mol Biol ; 70(4): 421-42, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19343509

RESUMO

Plant acyl-CoA dependent acyltransferases constitute a large specific protein superfamily, named BAHD. Using the conserved sequence motifs of BAHD members, we searched the genome sequences of Populus and Arabidopsis, and identified, respectively, 94- and 61-putative genes. Subsequently, we analyzed the phylogeny, gene structure, and chromosomal distribution of BAHD members of both species; then, we profiled expression patterns of BAHD genes by "in silico" northern- and microarray-analyses based on public databases, and by RT-PCR. While our genomic- and bioinformatic- analyses provided full sets of BAHD superfamily genes, and cleaned up a few existing annotation errors, importantly it led to our recognizing several unique Arabidopsis BAHD genes that inversely overlapped with their neighboring genes on the genome, and disclosing a potential natural anti-sense regulation for gene expressions. Systemic gene-expression profiling of BAHD members revealed distinct tissue-specific/preferential expression patterns, indicating their diverse biological functions. Our study affords a strong knowledge base for understanding BAHD members' evolutionary relationships and gene functions implicated in plant growth, development and metabolism.


Assuntos
Aciltransferases/genética , Arabidopsis/enzimologia , Proteínas de Plantas/genética , Populus/enzimologia , Acil Coenzima A/metabolismo , Aciltransferases/classificação , Aciltransferases/metabolismo , Sequência de Aminoácidos , Arabidopsis/genética , Mapeamento Cromossômico , Cromossomos de Plantas/genética , Bases de Dados de Ácidos Nucleicos/estatística & dados numéricos , Regulação Enzimológica da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Dados de Sequência Molecular , Família Multigênica , Análise de Sequência com Séries de Oligonucleotídeos/estatística & dados numéricos , Filogenia , Proteínas de Plantas/metabolismo , Populus/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa
14.
Planta ; 229(1): 15-24, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18820945

RESUMO

Acylesterification is one of the common modifications of cell wall non-cellulosic polysaccharides and/or lignin primarily in monocot plants. We analyzed the cell-wall acylesters of black cottonwood (Populus trichocarpa Torr. & Gray) with liquid chromatography-mass spectrometry (LC-MS), Fourier transform-infrared (FT-IR) microspectroscopy, and synchrotron infrared (IR) imaging facility. The results revealed that the cell wall of dicotyledonous poplar, as the walls of many monocot grasses, contains a considerable amount of acylesters, primarily acetyl and p-hydroxycinnamoyl molecules. The "wall-bound" acetate and phenolics display a distinct tissue specific-, bending stress responsible- and developmental-accumulation pattern. The "wall-bound" p-coumarate predominantly accumulated in young leaves and decreased in mature leaves, whereas acetate and ferulate mostly amassed in the cell wall of stems. Along the development of stem, the level of the "wall-bound" ferulate gradually increased, while the basal level of p-coumarate further decreased. Induction of tension wood decreased the accumulation of the "wall-bound" phenolics while the level of acetate remained constant. Synchrotron IR-mediated chemical compositional imaging revealed a close spatial distribution of acylesters with cell wall polysaccharides in poplar stem. These results indicate that different "wall-bound" acylesters play distinct roles in poplar cell wall structural construction and/or metabolism of cell wall matrix components.


Assuntos
Parede Celular/química , Ésteres/análise , Populus/química , Madeira/metabolismo , Acilação , Ácidos Cumáricos/análise , Lignina/metabolismo , Especificidade de Órgãos , Espectrometria de Massas por Ionização por Electrospray , Espectroscopia de Infravermelho com Transformada de Fourier
15.
Cell Res ; 17(5): 422-34, 2007 May.
Artigo em Inglês | MEDLINE | ID: mdl-17387330

RESUMO

Cotton fibers elongate rapidly after initiation of elongation, eventually leading to the deposit of a large amount of cellulose. To reveal features of cotton fiber cells at the fast elongation and the secondary cell wall synthesis stages, we compared the respective transcriptomes and metabolite profiles. Comparative analysis of transcriptomes by cDNA array identified 633 genes that were differentially regulated during fiber development. Principal component analysis (PCA) using expressed genes as variables divided fiber samples into four groups, which are diagnostic of developmental stages. Similar grouping results are also found if we use non-polar or polar metabolites as variables for PCA of developing fibers. Auxin signaling, wall-loosening and lipid metabolism are highly active during fiber elongation, whereas cellulose biosynthesis is predominant and many other metabolic pathways are downregulated at the secondary cell wall synthesis stage. Transcript and metabolite profiles and enzyme activities are consistent in demonstrating a specialization process of cotton fiber development toward cellulose synthesis. These data demonstrate that cotton fiber cell at a certain stage has its own unique feature, and developmental stages of cotton fiber cells can be distinguished by their transcript and metabolite profiles. During the secondary cell wall synthesis stage, metabolic pathways are streamed into cellulose synthesis.


Assuntos
Fibra de Algodão , Gossypium/genética , Gossypium/metabolismo , Celulose/biossíntese , Etiquetas de Sequências Expressas , Perfilação da Expressão Gênica , Gossypium/citologia , Dados de Sequência Molecular , Análise de Sequência com Séries de Oligonucleotídeos
16.
Plant Cell ; 19(1): 163-81, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17220200

RESUMO

Phosphatidylinositol monophosphate 5-kinase (PIP5K) plays an essential role in coordinating plant growth, especially in response to environmental factors. To explore the physiological function of PIP5K, we characterized Arabidopsis thaliana PIP5K9, which is constitutively expressed. We found that a T-DNA insertion mutant, pip5k9-d, which showed enhanced PIP5K9 transcript levels, had shortened primary roots owing to reduced cell elongation. Transgenic plants overexpressing PIP5K9 displayed a similar root phenotype. Yeast two-hybrid assays identified a cytosolic invertase, CINV1, that interacted with PIP5K9, and the physiological relevance of this interaction was confirmed by coimmunoprecipitation studies using plant extracts. CINV1-deficient plants, cinv1, had reduced activities of both neutral and acid invertases as well as shortened roots. Invertase activities in pip5k9-d seedlings were also reduced, suggesting a negative regulation of CINV1 by PIP5K9. In vitro studies showed that PIP5K9 interaction indeed repressed CINV1 activities. Genome-wide expression studies revealed that genes involved in sugar metabolism and multiple developmental processes were altered in pip5k9-d and cinv1, and the altered sugar metabolism in these mutants was confirmed by metabolite profiling. Together, our results indicate that PIP5K9 interacts with CINV1 to negatively regulate sugar-mediated root cell elongation.


Assuntos
Proteínas de Arabidopsis/fisiologia , Arabidopsis/enzimologia , Fosfotransferases (Aceptor do Grupo Álcool)/fisiologia , Arabidopsis/anatomia & histologia , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Metabolismo dos Carboidratos/genética , Perfilação da Expressão Gênica , Dados de Sequência Molecular , Mutação , Fenótipo , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Fosfotransferases (Aceptor do Grupo Álcool)/metabolismo , Raízes de Plantas/anatomia & histologia , Raízes de Plantas/enzimologia , Raízes de Plantas/genética , RNA Mensageiro/metabolismo , Plântula/anatomia & histologia , Plântula/enzimologia , Plântula/genética , Transdução de Sinais , Técnicas do Sistema de Duplo-Híbrido , beta-Frutofuranosidase/antagonistas & inibidores , beta-Frutofuranosidase/genética , beta-Frutofuranosidase/metabolismo
17.
Plant Cell ; 16(9): 2323-34, 2004 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-15316114

RESUMO

Cotton (Gossypium spp) plants produce seed trichomes (cotton fibers) that are an important commodity worldwide; however, genes controlling cotton fiber development have not been characterized. In Arabidopsis thaliana the MYB gene GLABRA1 (GL1) is a central regulator of trichome development. Here, we show that promoter of a cotton fiber gene, RD22-like1 (RDL1), contains a homeodomain binding L1 box and a MYB binding motif that confer trichome-specific expression in Arabidopsis. A cotton MYB protein GaMYB2/Fiber Factor 1 transactivated the RDL1 promoter both in yeast and in planta. Real-time PCR and in situ analysis showed that GaMYB2 is predominantly expressed early in developing cotton fibers. After transferring into Arabidopsis, GL1::GaMYB2 rescued trichome formation of a gl1 mutant, and interestingly, 35S::GaMYB2 induced seed-trichome production. We further demonstrate that the first intron of both GL1 and GaMYB2 plays a role in patterning trichomes: it acts as an enhancer in trichome and a repressor in nontrichome cells, generating a trichome-specific pattern of MYB gene expression. Disruption of a MYB motif conserved in intron 1 of GL1, WEREWOLF, and GaMYB2 genes affected trichome production. These results suggest that cotton and Arabidopsis use similar transcription factors for regulating trichomes and that GaMYB2 may be a key regulator of cotton fiber development.


Assuntos
Regulação da Expressão Gênica de Plantas/genética , Genes myb/fisiologia , Gossypium/crescimento & desenvolvimento , Gossypium/genética , Sementes/crescimento & desenvolvimento , Sementes/genética , Fatores de Transcrição/genética , Motivos de Aminoácidos/genética , Elementos Facilitadores Genéticos/genética , Evolução Molecular , Técnicas de Transferência de Genes , Genes myb/genética , Gossypium/ultraestrutura , Íntrons/genética , Microscopia Eletrônica de Varredura , Dados de Sequência Molecular , Filogenia , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Plantas Geneticamente Modificadas/metabolismo , Regiões Promotoras Genéticas/genética , Estrutura Terciária de Proteína/genética , Proteínas Repressoras/genética , Sementes/ultraestrutura , Fatores de Transcrição/metabolismo
18.
Appl Environ Microbiol ; 70(8): 4989-95, 2004 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15294839

RESUMO

Verticillium wilt is a vascular disease of cotton. The causal fungus, Verticillium dahliae, secretes elicitors in culture. We have generated approximately 1,000 5'-terminal expressed sequence tags (ESTs) from a cultured mycelium of V. dahliae. A number of ESTs were found to encode proteins harboring putative signal peptides for secretion, and their cDNAs were isolated. Heterologous expression led to the identification of a protein with elicitor activities. This protein, named V. dahliae necrosis- and ethylene-inducing protein (VdNEP), is composed of 233 amino acids and has high sequence identities with fungal necrosis- and ethylene-inducing proteins. Infiltration of the bacterially expressed His-VdNEP into Nicotiana benthamiana leaves resulted in necrotic lesion formation. In Arabidopsis thaliana, the fusion protein also triggered production of reactive oxygen species and induced the expression of PR genes. When added into suspension cultured cells of cotton (Gossypium arboreum), the fusion protein elicited the biosynthesis of gossypol and related sesquiterpene phytoalexins at low concentrations, and it induced cell death at higher concentrations. On cotton cotyledons and leaves, His-VdNEP induced dehydration and wilting, similar to symptoms caused by a crude preparation of V. dahliae elicitors. Northern blotting showed a low level of VdNEP expression in the mycelium during culture. These data suggest that VdNEP is a wilt-inducing factor and that it participates in cotton-V. dahliae interactions.


Assuntos
Proteínas Fúngicas/metabolismo , Gossypium/microbiologia , Doenças das Plantas/microbiologia , Verticillium/patogenicidade , Arabidopsis/microbiologia , DNA Complementar/genética , Etilenos/metabolismo , Etiquetas de Sequências Expressas , Proteínas Fúngicas/genética , Regulação da Expressão Gênica de Plantas , Dados de Sequência Molecular , Necrose , Análise de Sequência de DNA , Tabaco/microbiologia , Verticillium/metabolismo
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