RESUMO
Proteases play a main role in the mobilization of storage proteins during seed germination. Until today, there is little information about the involvement of serine proteases, particularly subtilases, in the germination of barley grains. The aims of the present work were to study the contribution of serine proteases to the total proteolytic activity induced during germination of barley grains and evaluate the specific involvement of subtilases in this process. Proteolytic activity assayed against azocasein in the presence of specific inhibitors, showed that serine proteases contributed between 10 and 20% of total activity along germination. Subtilase activity increased from day 1 after imbibition with a peak between days 4-5. Moreover, in vivo determination of subtilase activity in germinating grains revealed increasing activity along germination mainly localized in the seed endosperm and developing rootlets. Finally, the expression of 19 barley genes encoding subtilases was measured by real time PCR during germination. Three of the analyzed genes increased their expression along germination, five showed a transient induction, one was down-regulated, nine remained unchanged and one was not expressed. The present work demonstrates the involvement of subtilases in germination of barley grains and describes the positive association of eight subtilase genes to this process.
Assuntos
Germinação , Hordeum/crescimento & desenvolvimento , Proteínas de Plantas/metabolismo , Plântula/crescimento & desenvolvimento , Subtilisinas/metabolismo , Aminoácidos/metabolismo , Regulação da Expressão Gênica de Plantas , Hordeum/enzimologia , Hordeum/metabolismo , Proteólise , Reação em Cadeia da Polimerase em Tempo Real , Plântula/enzimologia , Plântula/metabolismoRESUMO
Barley malting quality depends on seed characteristics achieved during grain development and germination. One important parameter is protein accumulation in the mature seed, which may vary between cultivars. Here we conducted a protein pattern analysis in the range of pI 4-7 of mature grains from five Mexican barley cultivars, commonly used for malt and beer production. Reproducibly distinct protein spots, separated by 2D SDS PAGE, were identified by mass spectrometry and considered as potential markers for cultivars with distinct seed protein accumulation. The expression patterns of glutamate decarboxylase (GAD) and protein disulfide isomerase (PDI1-1) were followed at transcript level during grain development for three independent growth cycles to establish whether differences between cultivars were reproducible. Quantitative determination of PDI1-1 protein levels by ELISA confirmed a reproducibly, distinctive accumulation and post-translational modifications between cultivars, which were independent of plant growth regimes. According to its impact on differential storage protein accumulation, we propose the PDI1-1 protein as potential biomarker for Mexican malting barley cultivars.
Assuntos
Regulação da Expressão Gênica de Plantas , Hordeum/enzimologia , Hordeum/genética , Isomerases de Dissulfetos de Proteínas/genética , Isomerases de Dissulfetos de Proteínas/metabolismo , Processamento de Proteína Pós-Traducional , Glicosilação , Hordeum/crescimento & desenvolvimento , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Sementes/crescimento & desenvolvimentoRESUMO
Phosphatidic acid (PA) is an important bioactive lipid that mediates chilling responses in barley. Modifications in the lipid composition of cellular membranes during chilling are essential to maintain their integrity and fluidity. First, we investigated the molecular species of PA present in leaves and roots by ESI-MS/MS, to evaluate the modifications that occur in response to chilling. We demonstrated that PA pools in leaves differ from PA fatty acid composition in roots. Compared with plants grown at 25⯰C, the short-term and long-term chilling for 3â¯h and 36â¯hâ¯at 4⯰C not produced significant changes in PA molecular species. The endogenous DAG and PA phosphorylation by in vitro DAG and PA kinase activities showed higher activity in leaves compared with that in root, and they showed contrasting responses to chilling. Similarly, PA removal by phosphatidate phosphohydrolase was tested, showing that this activity was specifically increased in response to chilling in roots. The findings presented here may be helpful to understand how the PA signal is modulated between tissues, and may serve to highlight the importance of knowing the basal PA pools in different plant organs.
Assuntos
Temperatura Baixa , Hordeum/metabolismo , Ácidos Fosfatídicos/metabolismo , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Diglicerídeos/metabolismo , Análise Fatorial , Hordeum/enzimologia , Monoglicerídeos/metabolismo , Solubilidade , Espectrometria de Massas por Ionização por Electrospray , Água/químicaRESUMO
Abstract Agricultural crops suffer many diseases, including fungal and bacterial infections, causing significant yield losses. The identification and characterisation of pathogenesis-related protein genes, such as chitinases, can lead to reduction in pathogen growth, thereby increasing tolerance against fungal pathogens. In the present study, the chitinase I gene was isolated from the genomic DNA of Barley (Hordeum vulgare L.) cultivar, Haider-93. The isolated DNA was used as template for the amplification of the ∼935 bp full-length chitinase I gene. Based on the sequence of the amplified gene fragment, class I barley chitinase shares 93% amino acid sequence homology with class II wheat chitinase. Interestingly, barley class I chitinase and class II chitinase do not share sequence homology. Furthermore, the amplified fragment was expressed in Escherichia coli Rosetta strain under the control of T7 promoter in pET 30a vector. Recombinant chitinase protein of 35 kDa exhibited highest expression at 0.5 mM concentration of IPTG. Expressed recombinant protein of 35 kDa was purified to homogeneity with affinity chromatography. Following purification, a Western blot assay for recombinant chitinase protein measuring 35 kDa was developed with His-tag specific antibodies. The purified recombinant chitinase protein was demonstrated to inhibit significantly the important phytopathogenic fungi Alternaria solani, Fusarium spp, Rhizoctonia solani and Verticillium dahliae compared to the control at concentrations of 80 µg and 200 µg.
Assuntos
Antifúngicos/farmacologia , Quitinases/farmacologia , Hordeum/enzimologia , Proteínas Recombinantes/metabolismo , Antifúngicos/química , Antifúngicos/isolamento & purificação , Western Blotting , Quitinases/química , Quitinases/genética , Quitinases/isolamento & purificação , Cromatografia de Afinidade , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Hordeum/genética , Peso Molecular , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Homologia de Sequência de AminoácidosRESUMO
Agricultural crops suffer many diseases, including fungal and bacterial infections, causing significant yield losses. The identification and characterisation of pathogenesis-related protein genes, such as chitinases, can lead to reduction in pathogen growth, thereby increasing tolerance against fungal pathogens. In the present study, the chitinase I gene was isolated from the genomic DNA of Barley (Hordeum vulgare L.) cultivar, Haider-93. The isolated DNA was used as template for the amplification of the â¼935bp full-length chitinase I gene. Based on the sequence of the amplified gene fragment, class I barley chitinase shares 93% amino acid sequence homology with class II wheat chitinase. Interestingly, barley class I chitinase and class II chitinase do not share sequence homology. Furthermore, the amplified fragment was expressed in Escherichia coli Rosetta strain under the control of T7 promoter in pET 30a vector. Recombinant chitinase protein of 35kDa exhibited highest expression at 0.5mM concentration of IPTG. Expressed recombinant protein of 35kDa was purified to homogeneity with affinity chromatography. Following purification, a Western blot assay for recombinant chitinase protein measuring 35kDa was developed with His-tag specific antibodies. The purified recombinant chitinase protein was demonstrated to inhibit significantly the important phytopathogenic fungi Alternaria solani, Fusarium spp, Rhizoctonia solani and Verticillium dahliae compared to the control at concentrations of 80µg and 200µg.
Assuntos
Antifúngicos/farmacologia , Quitinases/farmacologia , Hordeum/enzimologia , Proteínas Recombinantes/metabolismo , Antifúngicos/química , Antifúngicos/isolamento & purificação , Western Blotting , Quitinases/química , Quitinases/genética , Quitinases/isolamento & purificação , Cromatografia de Afinidade , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Hordeum/genética , Peso Molecular , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Homologia de Sequência de AminoácidosRESUMO
Background: The enzymes utilized in the process of beer production are generally sensitive to higher temperatures. About 60% of them are deactivated in drying the malt that limits the utilization of starting material in the fermentation process. Gene transfer from thermophilic bacteria is a promising tool for producing barley grains harboring thermotolerant enzymes. Results: Gene for α-amylase from hydrothermal Thermococcus, optimally active at 7585°C and pH between 5.0 and 5.5, was adapted in silico to barley codon usage. The corresponding sequence was put under control of the endosperm-specific promoter 1Dx5 and after synthesis and cloning transferred into barley by biolistics. In addition to model cultivar Golden Promise we transformed three Slovak barley cultivars Pribina, Levan and Nitran, and transgenic plants were obtained. Expression of the ~50 kDa active recombinant enzyme in grains of cvs. Pribina and Nitran resulted in retaining up to 9.39% of enzyme activity upon heating to 75°C, which is more than 4 times higher compared to non-transgenic controls. In the model cv. Golden Promise the grain α-amylase activity upon heating was above 9% either, however, the effects of the introduced enzyme were less pronounced (only 1.22 fold difference compared with non-transgenic barley). Conclusions: Expression of the synthetic gene in barley enhanced the residual α-amylase activity in grains at high temperatures.
Assuntos
Sementes/enzimologia , Hordeum/enzimologia , Thermococcus/metabolismo , alfa-Amilases/metabolismo , Sementes/genética , Sementes/microbiologia , Transformação Genética , Hordeum/genética , Hordeum/microbiologia , Cerveja , Estabilidade Enzimática , Plantas Geneticamente Modificadas/enzimologia , Clonagem Molecular , Técnicas de Transferência de Genes , alfa-Amilases/genética , Fermentação , Termotolerância , Temperatura Alta , Concentração de Íons de HidrogênioRESUMO
Starch branching enzyme is a highly conserved protein from plants to algae. This enzyme participates in starch granule assembly by the addition of α-1,6-glucan branches to the α-1,4-polyglucans. This modification determines the structure of amylopectin thus arranging the final composition of the starch granule. Herein, we describe the function of the Ot01g03030 gene from the picoalgae Ostreococcus tauri. Although in silico analysis suggested that this gene codes for a starch debranching enzyme, our biochemical studies support that this gene encodes a branching enzyme (BE). The resulting 1058 amino acids protein has two in tandem carbohydrate binding domains (CBMs, from the CBM41 and CBM48 families) at the N-terminal (residues 64-403) followed by the C-terminal catalytic domain (residues 426-1058). Analysis of the BE truncated isoforms show that the CBMs bind differentially to whole starch, amylose or amylopectin. Furthermore, both CBMs seem to be essential for BE activity, as no catalytic activity was detected in the truncated enzyme comprising only by the catalytic domain. Our results suggest that the Ot01g03030 gene codifies for a functional BE containing two CBMs from CBM41 and CBM48 families which are critical for enzyme function and regulation.
Assuntos
Clorófitas/enzimologia , Enzimas/química , Amido/química , Amilopectina/química , Carboidratos/química , Catálise , Domínio Catalítico , Dicroísmo Circular , Clonagem Molecular , Hordeum/enzimologia , Cinética , Filogenia , Polissacarídeos/química , Domínios Proteicos , Proteínas Recombinantes/químicaRESUMO
Protecting group-free synthesis of 1,2:5,6-di-anhydro-D-mannitol, followed by ring opening with propargylamine and subsequent ring closure produced a separable mix of piperidine N-propargyl 1,5-dideoxy-1,5-imino-D-gulitol and azepane N-propargyl 1,6-dideoxy-1,6-imino-D-mannitol. In O-acetylated form, these two building blocks were subjected to CuAAC click chemistry with a panel of three differently azide-substituted glucose building blocks, producing iminosugar pseudo-disaccharides in good yield. The overall panel of eight compounds, plus 1-deoxynojirimycin (DNJ) as a benchmark, was evaluated as prospective inhibitors of almond ß-glucosidase, yeast α-glucosidase and barley ß-amylase. The iminosugar pseudo-disaccharides showed no inhibitory activity against almond ß-glucosidase, while the parent N-propargyl 1,5-dideoxy-1,5-imino-D-gulitol and N-propargyl 1,6-dideoxy-1,6-imino-D-mannitol likewise proved to be inactive against yeast α-glucosidase. Inhibitory activity could be reinstated in the former series by appropriate substitution on nitrogen. The greater activity of the piperidine could be rationalized based on docking studies. Further, potent inhibition of ß-amylase was observed with compounds from both the piperidine and azepane series.
Assuntos
Inibidores Enzimáticos/síntese química , Compostos Heterocíclicos com 1 Anel/síntese química , Imino Açúcares/síntese química , Piperidinas/síntese química , Triazóis/síntese química , alfa-Glucosidases/química , beta-Amilase/química , beta-Glucosidase/química , 1-Desoxinojirimicina/química , Azidas/química , Química Click/métodos , Dissacarídeos/química , Inibidores Enzimáticos/química , Glucose/química , Compostos Heterocíclicos com 1 Anel/química , Hordeum/química , Hordeum/enzimologia , Imino Açúcares/química , Manitol/química , Pargilina/análogos & derivados , Pargilina/química , Piperidinas/química , Propilaminas/química , Prunus dulcis/química , Prunus dulcis/enzimologia , Saccharomyces cerevisiae/química , Saccharomyces cerevisiae/enzimologia , Triazóis/química , beta-Amilase/antagonistas & inibidores , beta-Glucosidase/antagonistas & inibidoresRESUMO
We analyzed lipid kinase and lipid phosphatase activities and determined endogenous phytohormone levels by liquid chromatography-tandem mass spectrometry in root and coleoptile tissues following germination of barley (Hordeum vulgare) seeds. The enzymes showing highest activity in aleurone cells were diacylglycerol kinase (DAG-k, EC 2.7.1.107) and phosphatidate kinase (PA-k). The ratio of gibberellins (GAs) to abscisic acid (ABA) was 2-fold higher in aleurone than in coleoptile or root tissues. In coleoptiles, phosphatidylinositol 4-kinase (PI4-k, EC 2.7.1.67) showed the highest enzyme activity, and jasmonic acid (JA) level was higher than in aleurone. In roots, activities of PI4-k, DAG-k, and PA-k were similar, and salicylic acid (SA) showed the highest concentration. In the assays to evaluate the hydrolysis of DGPP (diacylglycerol pyrophosphate) and PA (phosphatidic acid) we observed that PA hydrolysis by LPPs (lipid phosphate phosphatases) was not modified; however, the diacylglycerol pyrophosphate phosphatase (DGPPase) was strikingly higher in coleoptile and root tissues than to aleurone. Relevance of these findings in terms of signaling responses and seedling growth is discussed.
Assuntos
Cotilédone/metabolismo , Hordeum/enzimologia , Monoéster Fosfórico Hidrolases/metabolismo , Fosfotransferases/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Raízes de Plantas/metabolismo , Sementes/metabolismo , 1-Fosfatidilinositol 4-Quinase/metabolismo , Diacilglicerol Quinase/metabolismo , Difosfatos/metabolismo , Germinação/fisiologia , Glicerol/análogos & derivados , Glicerol/metabolismo , Glicerofosfatos/metabolismo , Hordeum/crescimento & desenvolvimento , Hordeum/metabolismo , Fosfatidato Fosfatase/metabolismo , Ácidos Fosfatídicos/metabolismo , Fosfotransferases (Aceptor do Grupo Fosfato)/metabolismo , Proteínas de Plantas/metabolismo , Pirofosfatases/metabolismo , Transdução de SinaisRESUMO
Sib-seedlings of 95 strains of the strictly autogamous grass Hordeum euclaston were analyzed by horizontal polyacrylamide gel electrophoresis for four isoenzyme systems at a specific ontogenetic stage. We found differences in the activity of some genes among individuals of this species. Hence, an ontogenetic analysis was carried out to investigate 12 strains at five ontogenetic stages, to determine the patterns of expression of these genes during development. The differences in the presence versus absence of certain isoenzyme bands may be due to differential regulatory activation in response to environmental differences, as all plants showed the same structural genes, although these genes were active in different tissues and/or times of development. These results indicate the importance of differential gene activation in the metabolic phenotype variability of this strictly autogamous, highly homozygous species. The same structural alleles for isoenzymes showed the active form of the enzymes (phenotypic expression) to be present in different tissues and/or stages of development. Differential isoenzyme gene activation was shown to be directly responsible for the enzymatic variability (metabolic phenotype) presented by the plants, which seem to possess almost no heterozygosis.