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1.
Plant Cell ; 36(5): 2000-2020, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38299379

RESUMO

The flower-infecting fungus Ustilaginoidea virens causes rice false smut, which is a severe emerging disease threatening rice (Oryza sativa) production worldwide. False smut not only reduces yield, but more importantly produces toxins on grains, posing a great threat to food safety. U. virens invades spikelets via the gap between the 2 bracts (lemma and palea) enclosing the floret and specifically infects the stamen and pistil. Molecular mechanisms for the U. virens-rice interaction are largely unknown. Here, we demonstrate that rice flowers predominantly employ chitin-triggered immunity against U. virens in the lemma and palea, rather than in the stamen and pistil. We identify a crucial U. virens virulence factor, named UvGH18.1, which carries glycoside hydrolase activity. Mechanistically, UvGH18.1 functions by binding to and hydrolyzing immune elicitor chitin and interacting with the chitin receptor CHITIN ELICITOR BINDING PROTEIN (OsCEBiP) and co-receptor CHITIN ELICITOR RECEPTOR KINASE1 (OsCERK1) to impair their chitin-induced dimerization, suppressing host immunity exerted at the lemma and palea for gaining access to the stamen and pistil. Conversely, pretreatment on spikelets with chitin induces a defense response in the lemma and palea, promoting resistance against U. virens. Collectively, our data uncover a mechanism for a U. virens virulence factor and the critical location of the host-pathogen interaction in flowers and provide a potential strategy to control rice false smut disease.


Assuntos
Quitina , Flores , Hypocreales , Oryza , Doenças das Plantas , Oryza/microbiologia , Oryza/metabolismo , Oryza/genética , Doenças das Plantas/microbiologia , Quitina/metabolismo , Flores/microbiologia , Hypocreales/patogenicidade , Hypocreales/genética , Hypocreales/metabolismo , Transdução de Sinais , Interações Hospedeiro-Patógeno , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Virulência , Fatores de Virulência/metabolismo , Fatores de Virulência/genética , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/genética
2.
Mol Plant ; 15(11): 1790-1806, 2022 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-36245122

RESUMO

Grain formation is fundamental for crop yield but is vulnerable to abiotic and biotic stresses. Rice grain production is threatened by the false smut fungus Ustilaginoidea virens, which specifically infects rice floral organs, disrupting fertilization and seed formation. However, little is known about the molecular mechanisms of the U. virens-rice interaction and the genetic basis of floral resistance. Here, we report that U. virens secretes a cytoplasmic effector, UvCBP1, to facilitate infection of rice flowers. Mechanistically, UvCBP1 interacts with the rice scaffold protein OsRACK1A and competes its interaction with the reduced nicotinamide adenine dinucleotide phosphate oxidase OsRBOHB, leading to inhibition of reactive oxygen species (ROS) production. Although the analysis of natural variation revealed no OsRACK1A variants that could avoid being targeted by UvCBP1, expression levels of OsRACK1A are correlated with field resistance against U. virens in rice germplasm. Overproduction of OsRACK1A restores the OsRACK1A-OsRBOHB association and promotes OsRBOHB phosphorylation to enhance ROS production, conferring rice floral resistance to U. virens without yield penalty. Taken together, our findings reveal a new pathogenic mechanism mediated by an essential effector from a flower-specific pathogen and provide a valuable genetic resource for balancing disease resistance and crop yield.


Assuntos
Oryza , Oryza/genética , Oryza/microbiologia , Espécies Reativas de Oxigênio , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Flores/genética , Flores/microbiologia , Sementes
3.
Int J Mol Sci ; 16(3): 4731-43, 2015 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-25739085

RESUMO

Urena lobata has been used as a traditional medicinal plant in India and China. In this study, we investigated the antimicrobial activity and isolated the active compound from the leaves of U. lobata. The 80% ethanol extract from U. lobata leaves showed an effective anti-yeast activity against Saccharomyces cerevisiae (S. cerevisiae) strains. Using a combination of chromatographic methods, (-)-trachelogenin (1) and clematoside-S (2) were isolated from this plant for the first time, and their chemical structure was identified by mass spectrometry (MS) and extensive nuclear magnetic resonance (NMR) data analysis. In addition, 1 was found to be inactive against all of the test microorganisms in the antimicrobial assay, whereas 2 exhibits a specific anti-yeast activity against S. cerevisiae strains with diameter of inhibition zones in the range from 11 to 20 mm. Furthermore, the MIC (minimum inhibitory concentration) and MBC (minimum bactericidal concentration) values of 2 against S. cerevisiae strains were detected to be in the ranges of 0.61 to 9.8 µg/mL and 2.42 to 9.8 µg/mL, respectively. This is the first report of 2 with a specific anti-yeast activity. The above result suggests the potential application of U. lobata to be used as a natural anti-yeast agent in food preservation.


Assuntos
Malvaceae/química , Ácido Oleanólico/análogos & derivados , Saccharomyces cerevisiae/efeitos dos fármacos , Descoberta de Drogas , Etanol/química , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Testes de Sensibilidade Microbiana , Estrutura Molecular , Ácido Oleanólico/química , Ácido Oleanólico/farmacologia , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Folhas de Planta/química , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saponinas/química , Saponinas/farmacologia , Triterpenos/química , Triterpenos/farmacologia
4.
Int J Mol Sci ; 14(10): 20204-19, 2013 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-24152437

RESUMO

The prolyl oligopeptidase family, which is a group of serine peptidases, can hydrolyze peptides smaller than 30 residues. The prolyl oligopeptidase family in plants includes four members, which are prolyl oligopeptidase (POP, EC3.4.21.26), dipeptidyl peptidase IV (DPPIV, EC3.4.14.5), oligopeptidase B (OPB, EC3.4.21.83), and acylaminoacyl peptidase (ACPH, EC3.4.19.1). POP is found in human and rat, and plays important roles in multiple biological processes, such as protein secretion, maturation and degradation of peptide hormones, and neuropathies, signal transduction and memory and learning. However, the function of POP is unclear in plants. In order to study POP function in plants, we cloned the cDNA of the OsPOP5 gene from rice by nested-PCR. Sequence analysis showed that the cDNA encodes a protein of 596 amino acid residues with Mw ≈ 67.29 kD. In order to analyze the protein function under different abiotic stresses, OsPOP5 was expressed in Escherichia coli. OsPOP5 protein enhanced the tolerance of E. coli to high salinity, high temperature and simulated drought. The results indicate that OsPOP5 is a stress-related gene in rice and it may play an important role in plant tolerance to abiotic stress.


Assuntos
Escherichia coli/genética , Genes de Plantas/genética , Oryza/genética , Serina Endopeptidases/genética , Estresse Fisiológico/genética , Sequência de Bases , Dados de Sequência Molecular , Oryza/enzimologia , Filogenia , Prolil Oligopeptidases
5.
Plant Sci ; 208: 83-92, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23683933

RESUMO

The nuclear matrix is involved in many nuclear events, but its protein architecture in plants is still not fully understood. A cDNA clone was isolated by immunoscreening with a monoclonal antibody raised against nuclear matrix proteins of Daucus carota L. Its deduced amino acid sequence showed about 40% identity with the PESCADILLO protein of zebrafish and humans. Primary structure analysis of the protein revealed a Pescadillo N-terminus domain, a single breast cancer C-terminal domain, two nuclear localization signals, and a potential coiled-coil region as also found in animal PESCADILLO proteins. Therefore, we designated this gene DcPES1. Although DcPES1 mRNA was detected in all tissues examined, its levels were highest in tissues with proliferating cells. Immunofluorescence using specific antiserum against the recombinant protein revealed that DcPES1 localized exclusively in the nucleolus. Examination of fusion proteins with green fluorescent protein revealed that the N-terminal portion was important for localization to the nucleoli of tobacco and onion cells. Moreover, when the nuclear matrix of carrot cells was immunostained with an anti-DcPES1 serum, the signal was detected in the nucleolus. Therefore, the DcPES1 protein appears to be a component of or tightly bound to components of the nuclear matrix.


Assuntos
Daucus carota/metabolismo , Proteínas Nucleares/química , Proteínas de Plantas/química , Proteínas de Plantas/isolamento & purificação , Homologia de Sequência de Aminoácidos , Homologia Estrutural de Proteína , Vertebrados/metabolismo , Sequência de Aminoácidos , Animais , Nucléolo Celular/metabolismo , DNA Complementar/isolamento & purificação , Daucus carota/citologia , Daucus carota/genética , Regulação da Expressão Gênica de Plantas , Humanos , Dados de Sequência Molecular , Matriz Nuclear/metabolismo , Proteínas Nucleares/genética , Proteínas Nucleares/isolamento & purificação , Proteínas Nucleares/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Estrutura Terciária de Proteína , Transporte Proteico , Frações Subcelulares/metabolismo , Nicotiana/citologia , Peixe-Zebra
6.
Biosci Biotechnol Biochem ; 72(2): 615-7, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18256478

RESUMO

Recently, much research on constitutive expression of an intron-containing self-complementary hair-pin RNA (ihpRNA) have been reported to silence target genes efficiently in a variety of species. Here we designed a new recombinant-PCR mediated method called direct amplification of ihpRNA from genomic DNA. This approach has proved to be easy, stable, and efficient.


Assuntos
Íntrons , RNA/genética , Sequência de Bases , Inativação Gênica , Dados de Sequência Molecular , Reação em Cadeia da Polimerase
7.
Yi Chuan ; 28(3): 369-74, 2006 Mar.
Artigo em Chinês | MEDLINE | ID: mdl-16551608

RESUMO

DREB transcription factor is a dehydration responsive element (DRE) binding protein. It can specifically interact with the dehydration-responsive element/C-repeat (DRE/CRT) cis-acting element contained in the promoter region of many stress-inducible genes, and can therefore control the expression of many stress-inducible genes in plant and increase strong tolerance to drought, low temperature and high salt. In this paper we described the relation between DREB transcription factor and DRE/CRT cis-acting element, the functional and structural character, and expression and regulation of DREB. We also briefly introduced the progress of research on DREB gene cloning and identification. DREB transcription factor plays an important role in the expression of many stress-inducible genes in plant, so it thus shows a very broad application future in aspect of increasing strong tolerance to stress. At the same time, we described the DREB complexity in signal transduction and the mechanism for action and expression of gene.


Assuntos
Proteínas de Plantas/metabolismo , Proteínas de Plantas/fisiologia , Fatores de Transcrição/metabolismo , Fatores de Transcrição/fisiologia , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Fatores de Transcrição/genética
8.
Biosci Biotechnol Biochem ; 69(8): 1498-507, 2005 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16116277

RESUMO

Five full-length cDNA encoding gibberellin 2-oxidases, VaGA2oxA1, VaGA2oxA2, VaGA2oxB1, VaGA2oxB2, and VaGA2oxB3, were cloned from etiolated adzuki bean (Vigna angularis cv. Dainagon) seedlings, and their enzymatic characteristics were examined using recombinant enzymes fused with glutathione S-transferase (GST). Recombinant VaGA2oxA1 (rVaGA2oxA1) and rVaGA2oxA2 showed 2beta-hydroxylation activity by converting GA1, GA4, GA9, GA20, GA4-methyl ester, and 16,17-dihydro-GA4 to the corresponding 2beta-hydroxylated gibberellins, which were identified by GC/MS. rVaGA2oxB1, rVaGA2oxB2, and rVaGA2oxB3 showed similar activity by converting [3H4]-16,17-dihydro-GA4 to a metabolite showing an Rf value of 16,17-dihydro-GA34. RNA-blot analysis showed that VaGA2oxA1 and VaGA2oxA2 were the major ones expressed in etiolated hypocotyls. The addition of Co2+ instead of Fe2+ to the assay medium apparently reduced the enzymatic activity, but increased the binding of [3H4]-16,17-dihydro-GA4 to rVaGA2oxA1, indicating the possibility that VaGA2oxs can be detected as gibberellin-binding proteins under certain conditions.


Assuntos
Cobalto/farmacologia , Fabaceae/enzimologia , Giberelinas/metabolismo , Ácidos Cetoglutáricos/farmacologia , Oxigenases de Função Mista/metabolismo , Plântula/enzimologia , Sequência de Aminoácidos , Sequência de Bases , Clonagem Molecular , Primers do DNA , Fabaceae/crescimento & desenvolvimento , Oxigenases de Função Mista/química , Oxigenases de Função Mista/genética , Oxigenases de Função Mista/isolamento & purificação , Dados de Sequência Molecular , Filogenia , Ligação Proteica , Homologia de Sequência de Aminoácidos
9.
Biosci Biotechnol Biochem ; 68(3): 631-7, 2004 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15056897

RESUMO

Two full-length cDNAs encoding gibberellin 3-oxidases, InGA3ox1 and InGA3ox2, were cloned from developing seeds of morning glory (Ipomoea nil (Pharbitis nil) Choisy cv. Violet) with degenerate-PCR and RACEs. The RNA-blot analysis for these clones revealed that the InGA3ox2 gene was organ-specifically expressed in the developing seeds at 6-18 days after anthesis. In situ hybridization showed the signals of InGA3ox2 mRNA in the seed coat, suggesting that active gibberellins (GAs) were synthesized in the tissue, although no active GA was detected there by immunohistochemistry. In situ hybridization analysis for InAmy1 (former PnAmy1) mRNA showed that InAmy1 was also synthesized in the seed coat. Both InGA3ox2 and InAmy1 genes were expressed spatially overlapped without a clear time lag, suggesting that both active GAs and InAmy1 were synthesized almost simultaneously in seed coat and secreted to the integument. These observations support the idea that GAs play an important role in seed development by inducing alpha-amylase.


Assuntos
Giberelinas/metabolismo , Ipomoea/enzimologia , alfa-Amilases/biossíntese , Sequência de Aminoácidos , Proteínas de Arabidopsis/biossíntese , Proteínas de Arabidopsis/genética , Clonagem Molecular , DNA Complementar/genética , Escherichia coli/genética , Regulação da Expressão Gênica de Plantas/genética , Giberelinas/biossíntese , Ipomoea/efeitos dos fármacos , Ipomoea/genética , Oxigenases de Função Mista/genética , Oxigenases de Função Mista/metabolismo , Dados de Sequência Molecular , Sementes/efeitos dos fármacos , Sementes/enzimologia , Sementes/crescimento & desenvolvimento , Alinhamento de Sequência , Amido/metabolismo , alfa-Amilases/genética
10.
Plant Physiol ; 129(3): 1285-95, 2002 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12114582

RESUMO

The glycosylated forms of abscisic acid (ABA) have been identified from many plant species and are known to be the forms of ABA-catabolism, although their (physiological) roles have not yet been elucidated. ABA-glucosyltransferase (-GTase) is thought to play a key role in the glycosylation of ABA. We isolated an ABA-inducible GTase gene from UDP-GTase homologs obtained from adzuki bean (Vigna angularis) seedlings. The deduced amino acid sequence (accession no. AB065190) showed 30% to 44% identity with the known UDP-GTase homologs. The recombinant protein with a glutathione S-transferase-tag was expressed in Escherichia coli and showed enzymatic activity in an ABA-specific manner. The enzymatic activity was detected over a wide pH range from 5.0 to 9.0, the optimum range being between pH 6.0 and 7.3, in a citrate and Tris-HCl buffer. The product from racemic ABA and UDP-D-glucose was identified to be ABA-GE by gas chromatography/mass spectrometry. The recombinant GTase (rAOG) converted 2-trans-(+)-ABA better than (+)-S-ABA and (-)-R-ABA. Although trans-cinnamic acid was slightly converted to its conjugate by the GTase, (-)-PA was not at all. The mRNA level was increased by ABA application or by water stress and wounding. We suggest that the gene encodes an ABA-specific GTase and that its expression is regulated by environmental stress.


Assuntos
Ácido Abscísico/metabolismo , Fabaceae/genética , Glucosiltransferases/genética , Reguladores de Crescimento de Plantas/metabolismo , Ácido Abscísico/farmacologia , Sequência de Aminoácidos , Sequência de Bases , Northern Blotting , Southern Blotting , Clonagem Molecular , DNA Complementar/química , DNA Complementar/genética , Escherichia coli/genética , Fabaceae/efeitos dos fármacos , Fabaceae/enzimologia , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Glucosiltransferases/metabolismo , Concentração de Íons de Hidrogênio , Hipocótilo/enzimologia , Dados de Sequência Molecular , Reguladores de Crescimento de Plantas/farmacologia , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Análise de Sequência de DNA , Especificidade por Substrato , Trítio , Uridina Difosfato Glucose/farmacologia
11.
Gene ; 284(1-2): 225-31, 2002 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-11891063

RESUMO

A protein disulfide isomerase (PDI) coding sequence was cloned from a cDNA library derived from carrot (Daucus carota L.) somatic embryos. The cDNA is 2060 bp in length and encodes for a protein of 581 amino acids and molecular weight of 64.4 kDa. Primary structure analysis of the deduced protein revealed two thioredoxin-like active sites and an endoplasmic reticulum-retention signal at its C-terminus, which is also found in PDIs in plants and animals. Although between the carrot protein and other plant PDIs there is only about 30% identity, the active site regions are almost identical. The corresponding mRNA was found in varying amounts, in all tissues investigated. A recombinant protein expressed from the carrot cDNA clone effectively catalyzed both glutathione-insulin transhydrogenation and the oxidative renaturation of denatured RNase A. These results suggest that the protein coded for by the carrot gene is a novel member of the PDI family in plants. We therefore designated this novel carrot gene PDIL1. The protein expressed by the PDIL1 cDNA sequence had a highly acidic stretch at its N-terminal region (no such domain exists in known plant PDIs), and was located far from known plant PDIs on a maximum likelihood tree. The PDIL1 gene, together with closely-related genes identified in Arabidopsis and tomato, was suggested to belong to a novel subfamily of PDIs.


Assuntos
Daucus carota/genética , Isomerases de Dissulfetos de Proteínas/genética , Sequência de Aminoácidos , Clonagem Molecular , DNA Complementar/química , DNA Complementar/genética , DNA Complementar/isolamento & purificação , Daucus carota/enzimologia , Regulação Enzimológica da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Dados de Sequência Molecular , Filogenia , Alinhamento de Sequência , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos
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