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1.
PLoS One ; 15(7): e0235416, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32614884

RESUMO

Plectranthus amboinicus (Lour.) Spreng is an aromatic medicinal herb known for its therapeutic and nutritional properties attributed by the presence of monoterpene and sesquiterpene compounds. Up until now, research on terpenoid biosynthesis has focused on a few mint species with economic importance such as thyme and oregano, yet the terpene synthases responsible for monoterpene production in P. amboinicus have not been described. Here we report the isolation, heterologous expression and functional characterization of a terpene synthase involved in P. amboinicus terpenoid biosynthesis. A putative monoterpene synthase gene (PamTps1) from P. amboinicus was isolated with an open reading frame of 1797 bp encoding a predicted protein of 598 amino acids with molecular weight of 69.6 kDa. PamTps1 shares 60-70% amino acid sequence similarity with other known terpene synthases of Lamiaceae. The in vitro enzymatic activity of PamTps1 demonstrated the conversion of geranyl pyrophosphate and farnesyl pyrophosphate exclusively into linalool and nerolidol, respectively, and thus PamTps1 was classified as a linalool/nerolidol synthase. In vivo activity of PamTps1 in a recombinant Escherichia coli strain revealed production of linalool and nerolidol which correlated with its in vitro activity. This outcome validated the multi-substrate usage of this enzyme in producing linalool and nerolidol both in in vivo and in vitro systems. The transcript level of PamTps1 was prominent in the leaf during daytime as compared to the stem. Gas chromatography-mass spectrometry (GC-MS) and quantitative real-time PCR analyses showed that maximal linalool level was released during the daytime and lower at night following a diurnal circadian pattern which correlated with the PamTps1 expression pattern. The PamTps1 cloned herein provides a molecular basis for the terpenoid biosynthesis in this local herb that could be exploited for valuable production using metabolic engineering in both microbial and plant systems.


Assuntos
Alquil e Aril Transferases , Proteínas de Plantas , Plectranthus/enzimologia , Monoterpenos Acíclicos/metabolismo , Alquil e Aril Transferases/biossíntese , Alquil e Aril Transferases/química , Alquil e Aril Transferases/genética , Clonagem Molecular , Escherichia coli/genética , Folhas de Planta/enzimologia , Proteínas de Plantas/biossíntese , Proteínas de Plantas/química , Proteínas de Plantas/genética , Sesquiterpenos/metabolismo
2.
PLoS One ; 15(7): e0235556, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32614916

RESUMO

To gain a better insight into the selenium nanoparticle (nSe) benefits/toxicity, this experiment was carried out to address the behavior of bitter melon seedlings to nSe (0, 1, 4, 10, 30, and 50 mgL-1) or bulk form (selenate). Low doses of nSe increased biomass accumulation, while concentrations of 10 mgL-1 and above were associated with stem bending, impaired root meristem, and severe toxicity. Responses to nSe were distinct from that of bulk in that the nano-type exhibited a higher efficiency to stimulate growth and organogenesis than the bulk. The bulk form displayed higher phytotoxicity than the nano-type counterpart. According to the MSAP-based analysis, nSe mediated substantial variation in DNA cytosine methylation, reflecting the epigenetic modification. By increasing the concentration of nSe, the expression of the WRKY1 transcription factor linearly up-regulated (mean = 7.9-fold). Transcriptions of phenylalanine ammonia-lyase (PAL) and 4-Coumarate: CoA-ligase (4CL) genes were also induced. The nSe treatments at low concentrations enhanced the activity of leaf nitrate reductase (mean = 52%) in contrast with the treatment at toxic concentrations. The toxic concentration of nSe increased leaf proline concentration by 80%. The nSe supplement also stimulated the activities of peroxidase (mean = 35%) and catalase (mean = 10%) enzymes. The nSe-treated seedlings exhibited higher PAL activity (mean = 39%) and soluble phenols (mean = 50%). The nSe toxicity was associated with a disrupted differentiation of xylem conducting tissue. The callus formation and performance of the explants originated from the nSe-treated seedlings had a different trend than that of the control. This experiment provides new insights into the nSe-associated advantage/ cytotoxicity and further highlights the necessity of designing convincing studies to introduce novel methods for plant cell/tissue cultures and agriculture.


Assuntos
Metilação de DNA/efeitos dos fármacos , Epigênese Genética/efeitos dos fármacos , Momordica charantia/metabolismo , Nanopartículas/toxicidade , Selênio/química , Citosina/metabolismo , Momordica charantia/efeitos dos fármacos , Momordica charantia/crescimento & desenvolvimento , Nanopartículas/química , Nitrato Redutase/genética , Nitrato Redutase/metabolismo , Fenóis/metabolismo , Fenilalanina Amônia-Liase/genética , Fenilalanina Amônia-Liase/metabolismo , Folhas de Planta/enzimologia , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/anatomia & histologia , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Prolina/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Regulação para Cima/efeitos dos fármacos
3.
PLoS One ; 15(7): e0227466, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32678822

RESUMO

Trans-methylation reactions are intrinsic to cellular metabolism in all living organisms. In land plants, a range of substrate-specific methyltransferases catalyze the methylation of DNA, RNA, proteins, cell wall components and numerous species-specific metabolites, thereby providing means for growth and acclimation in various terrestrial habitats. Trans-methylation reactions consume vast amounts of S-adenosyl-L-methionine (SAM) as a methyl donor in several cellular compartments. The inhibitory reaction by-product, S-adenosyl-L-homocysteine (SAH), is continuously removed by SAH hydrolase (SAHH), which essentially maintains trans-methylation reactions in all living cells. Here we report on the evolutionary conservation and post-translational control of SAHH in land plants. We provide evidence suggesting that SAHH forms oligomeric protein complexes in phylogenetically divergent land plants and that the predominant protein complex is composed by a tetramer of the enzyme. Analysis of light-stress-induced adjustments of SAHH in Arabidopsis thaliana and Physcomitrella patens further suggests that regulatory actions may take place on the levels of protein complex formation and phosphorylation of this metabolically central enzyme. Collectively, these data suggest that plant adaptation to terrestrial environments involved evolution of regulatory mechanisms that adjust the trans-methylation machinery in response to environmental cues.


Assuntos
Adenosil-Homocisteinase/metabolismo , Proteínas de Arabidopsis/metabolismo , Arabidopsis/enzimologia , Evolução Molecular , Adenosil-Homocisteinase/classificação , Adenosil-Homocisteinase/genética , Sequência de Aminoácidos , Proteínas de Arabidopsis/classificação , Proteínas de Arabidopsis/genética , Eletroforese em Gel Bidimensional , Focalização Isoelétrica , Luz , Filogenia , Folhas de Planta/enzimologia , Processamento de Proteína Pós-Traducional/efeitos da radiação , RNA Mensageiro/metabolismo , Alinhamento de Sequência , Estresse Fisiológico
4.
PLoS One ; 15(5): e0232626, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32374762

RESUMO

The aim of this study is to determine the involvement of the flavonol-anthocyanin pathway on plant adaptation to biotic stress using the B.amyloliquefaciens QV15 to trigger blackberry metabolism and identify target genes to improve plant fitness and fruit quality. To achieve this goal, field-grown blackberries were root-inoculated with QV15 along its growth cycle. At fruiting, a transcriptomic analysis by RNA-Seq was performed on leaves and fruits of treated and non-treated field-grown blackberries after a sustained mildew outbreak; expression of the regulating and core genes of the Flavonol-Anthocyanin pathway were analysed by qPCR and metabolomic profiles by UHPLC/ESI-qTOF-MS; plant protection was found to be up to 88%. Overexpression of step-controlling genes in leaves and fruits, associated to lower concentration of flavonols and anthocyanins in QV15-treated plants, together with a higher protection suggest a phytoanticipin role for flavonols in blackberry; kempferol-3-O-rutinoside concentration was strikingly high. Overexpression of RuF3H (Flavonol-3-hidroxylase) suggests a pivotal role in the coordination of committing steps in this pathway, controlling carbon flux towards the different sinks. Furthermore, this C demand is supported by an activation of the photosynthetic machinery, and boosted by a coordinated control of ROS into a sub-lethal range, and associated to enhanced protection to biotic stress.


Assuntos
Adaptação Fisiológica , Antocianinas/metabolismo , Bacillus amyloliquefaciens/fisiologia , Sistema Enzimático do Citocromo P-450/fisiologia , Rubus/enzimologia , Rubus/microbiologia , Estresse Fisiológico , Sistema Enzimático do Citocromo P-450/genética , Frutas/enzimologia , Frutas/genética , Frutas/microbiologia , Regulação da Expressão Gênica de Plantas , Genes de Plantas/genética , Folhas de Planta/enzimologia , Folhas de Planta/microbiologia , Rubus/genética
5.
Artigo em Inglês | MEDLINE | ID: mdl-32335384

RESUMO

Glutamine synthetases (GS) play an essential role in Nitrogen assimilation. Nonetheless, information respecting the molecular functions of GS in drought tolerance (DT) is limited. Here we show that overexpressing cytosolic GS1 or plastidic GS2 gene in tobacco enhanced DT of both root and leaf tissues of the two transgenic seedlings (named as GS1-TR and GS2-TR). RNA-seq analysis on root tissues showed that 83 aquaporin (AQP) genes were identified. Among them, 37 differential expression genes (DEGs) were found in the GS1-TR roots under normal condition, and all were down-regulated; no any DEGs in the GS2-TR roots were found. Contrastingly, under drought, 28 and 32 DEGs of AQP were up-regulated in GS1-TR and GS2-TR roots, respectively. GC-MS analysis on leaf tissues showed that glutamine (Gln) concentrations were negatively correlated AQP expressions in the all four conditions, which suggests that Gln, as a signal molecule, can negatively regulate many AQP expressions. Prestress accumulation of sucrose and proline (Pro) and chlorophyll, and had higher activities of ROS scavengers also contribute the plant DT in both of the two transgenic plants under drought. In addition, 5-aminolevulinic acid (ALA) was up-accumulated in GS2-TR leaves solely under normal condition, which leads to its net photosynthetic rate higher than that in GS1-TR leaves. Last but not the less, the PYL-PP2C-SnRK2 core ABA-signaling pathway was uniquely activated in GS1-TR independent of drought stress (DS). Therefore, our results suggest a possible model reflecting how overexpression of wheat TaGS1 and TaGS2 regulate plant responses to drought.


Assuntos
Secas , Expressão Gênica , Glutamato-Amônia Ligase , Estresse Fisiológico , Tabaco , Triticum , Citosol/enzimologia , Glutamato-Amônia Ligase/genética , Glutamato-Amônia Ligase/metabolismo , Glutamina , Folhas de Planta/enzimologia , Folhas de Planta/genética , Plastídeos/enzimologia , Estresse Fisiológico/genética , Tabaco/genética , Triticum/enzimologia , Triticum/genética
6.
Bull Environ Contam Toxicol ; 104(5): 619-626, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32172338

RESUMO

Cadmium contamination of agricultural soils is a serious problem due to its toxic effects on health and yield of crop plants. This study investigates the potential of low-dose nano-TiO2 as soil nanoremediation on Cd toxicity in cowpea plants. To achieve this goal, cowpea seeds were germinated on Cd-spiked soils at 10 mg/kg for 14 days and later augmented with 100 mg nTiO2/kg (nTiO2-50 nm and bTiO2-68 nm, respectively). The results showed that chlorophylls were not altered by nano-TiO2 intervention. Cadmium partitioning in roots and leaves was reduced by the applied nano-TiO2 but significantly higher than control. Ascorbate peroxidase and catalase activities in roots and leaves were promoted by nano-TiO2 intervention compared to control and sole Cd, respectively. However, magnitudes of activity of enzyme activities were higher in nTiO2 compared to bTiO2 treatments. The enhanced enzymes activity led to reduced malonaldehyde content in plant tissues. The study concludes that soil application of nano-TiO2 could be a green alternative to ameliorate soil Cd toxicity in cowpea plants.


Assuntos
Cádmio/metabolismo , Nanopartículas/química , Estresse Oxidativo/efeitos dos fármacos , Poluentes do Solo/toxicidade , Titânio/farmacologia , Vigna/efeitos dos fármacos , Vigna/enzimologia , Antioxidantes/metabolismo , Ascorbato Peroxidases/metabolismo , Cádmio/toxicidade , Clorofila/metabolismo , Germinação , Malondialdeído/metabolismo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/enzimologia , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/enzimologia , Sementes , Solo/química , Poluentes do Solo/metabolismo , Titânio/química , Vigna/crescimento & desenvolvimento
7.
Artigo em Inglês | MEDLINE | ID: mdl-32004918

RESUMO

The replication of positive strand RNA viruses in plant cells is markedly influenced by the desaturation status of fatty acid chains in lipids of intracellular plant membranes. At present, little is known about the role of lipid desaturation in the replication of tobamoviruses. Therefore, we investigated the expression of fatty acid desaturase (FAD) genes and the fatty acid composition of pepper leaves inoculated with two different tobamoviruses. Obuda pepper virus (ObPV) inoculation induced a hypersensitive reaction (incompatible interaction) while Pepper mild mottle virus (PMMoV) inoculation caused a systemic infection (compatible interaction). Changes in the expression of 16 FADs were monitored in pepper leaves following ObPV and PMMoV inoculations. ObPV inoculation rapidly and markedly upregulated seven Δ12-FADs that encode enzymes putatively located in the endoplasmic reticulum membrane. In contrast, PMMoV inoculation resulted in a weaker but rapid upregulation of two Δ12-FADs and a Δ15-FAD. The expression of genes encoding plastidial FADs was not influenced neither by ObPV nor by PMMoV. In accordance with gene expression results, a significant accumulation of linoleic acid was observed by gas chromatography-mass spectrometry in ObPV-, but not in PMMoV-inoculated leaves. ObPV inoculation led to a marked accumulation of H2O2 in the inoculated leaves. Therefore, the effect of H2O2 treatments on the expression of six tobamovirus-inducible FADs was also studied. The expression of these FADs was upregulated to different degrees by H2O2 that correlated with ObPV-inducibility of these FADs. These results underline the importance of further studies on the role of pepper FADs in pepper-tobamovirus interactions.


Assuntos
Capsicum , Ácidos Graxos Dessaturases , Regulação da Expressão Gênica de Plantas , Tobamovirus , Capsicum/enzimologia , Capsicum/virologia , Ácidos Graxos Dessaturases/genética , Peróxido de Hidrogênio/metabolismo , Folhas de Planta/química , Folhas de Planta/enzimologia , Folhas de Planta/virologia , Tobamovirus/fisiologia
8.
J Food Sci ; 85(3): 535-544, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32027028

RESUMO

In this study, we characterized protease activities of 23 Ficus carica cultivars. Extracts of fruit, branch, and leaf of Masui Dauphine, one of the most representative F. carica cultivars in Japan, exhibited gelatin-hydrolyzing activity, both in the absence and presence of a cysteine protease-specific inhibitor, E-64, suggesting that not only ficin (classified as cysteine protease) but also collagenase (classified as serine protease) were involved in the digestion of gelatin. In the hydrolysis of (7-methoxycoumarin-4-yl)acetyl-l-Lys-l-Pro-l-Leu-Gly-l-Leu-[N3 -(2,4-dinitrophenyl)-l-2,3-diaminopropionyl]-l-Ala-l-Arg-NH2 , all branch extracts of 23 F. carica cultivars exhibited the activity both in the absence and presence of cysteine protease-specific inhibitor E-64, indicating that they contain ficin and collagenase. During digestion of acid-solubilized type I collagen by the branch extract of Masui Dauphine at 40-55 °C, collagen was completely digested in the absence of E-64, while it was partially digested in the presence of the inhibitor, indicating that the manner of digestion differed between ficin and collagenase contained in the extract. These results suggest that F. carica is attractive for industrial use to digest collagen. PRACTICAL APPLICATION: The industrial use of F. carica might be enhanced by efficiently utilizing these proteases and/or selecting the appropriate F. carica cultivar. Collagen is one of the targets to which our results might be applied. It is widely accepted today that collagen and its digestion products could be useful as functional food. F. carica is a potential candidate for use in not only complete but also partial digestion of collagen.


Assuntos
Ficus/enzimologia , Peptídeo Hidrolases/química , Proteínas de Plantas/química , Biocatálise , Colágeno/química , Ficus/química , Ficus/classificação , Ficus/genética , Frutas/química , Frutas/enzimologia , Frutas/genética , Japão , Peptídeo Hidrolases/genética , Peptídeo Hidrolases/metabolismo , Folhas de Planta/química , Folhas de Planta/enzimologia , Folhas de Planta/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Proteólise
9.
Plant Mol Biol ; 102(4-5): 463-475, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31916083

RESUMO

The mechanism by which endogenous salicylic acid (SA) regulates leaf senescence remains elusive. Here we provide direct evidence that an enhancement of endogenous SA level, via chemical-induced upregulation of ISOCHORISMATE SYNTHASE 1 (ICS1), could significantly accelerate the senescence process of old leaves through mediation of the key SA signaling component NON EXPRESSOR OF PATHOGENESIS RELATED GENES 1 (NPR1) in Arabidopsis. Importantly, by taking advantage of this chemically induced leaf senescence system, we identified a mitogen-activated protein kinase (MAPK) cascade MKK4/5-MPK1/2 that is required for the SA/NPR1-mediated leaf senescence. Both MKK4/5 and MPK1/2 exhibited SA-induced kinase activities, with MPK1/2 being the immediate targets of MKK4/5. Double mutants of mkk4 mkk5 and mpk1 mpk2 displayed delayed leaf senescence, while constitutive overexpression of the kinase genes led to premature leaf senescence. Such premature leaf senescence was suppressed when they were overexpressed in an SA synthesis defective mutant (sid2) or signaling detective mutant (npr1). We further showed that MPK1, but not MPK2, could directly phosphorylate NPR1. Meanwhile, MPK1 also mediated NPR1 monomerization. Notably, induction of disease resistance was significantly compromised in the single and double mutants of the kinase genes. Taken together, our data demonstrate that the MKK4/5-MPK1/2 cascade plays a critical role in modulating SA signaling through a complex regulatory network in Arabidopsis.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/enzimologia , Regulação da Expressão Gênica de Plantas , Sistema de Sinalização das MAP Quinases , Folhas de Planta/enzimologia , Ácido Salicílico/farmacologia , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Fosforilação , Folhas de Planta/genética , Plantas Geneticamente Modificadas/genética , Transdução de Sinais
10.
J Agric Food Chem ; 68(6): 1684-1690, 2020 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-31957431

RESUMO

The carotenoid-derived volatile ß-ionone plays an important role in the formation of green and black tea flavors due to its low odor threshold, but its formation and the gene(s) involved in its biosynthesis during the tea withering process is(are) still unknown. In this study, we found that the content of ß-ionone increased during the tea withering process catalyzed by an unknown enzyme(s). Correlation analysis of expression patterns of Camellia sinensis carotenoid cleavage dioxygenase genes (CsCCDs) and the ß-ionone content during the withering period revealed CsCCD4 as the most promising candidate. The full-length CsCCD4 gene was amplified from C. sinensis, and the biochemical function of the recombinant CsCCD4 protein was studied after coexpression in Escherichia coli strains engineered to accumulate ß-carotene. The recombinant protein was able to cleave a variety of carotenoids at the 9-10 and 9'-10' double bonds. Volatile ß-ionone was detected as the main product by gas and liquid chromatography-mass spectrometry. The accumulation of ß-ionone was consistent with the expression levels of CsCCD4 in different tissues and during the withering process. The CsCCD4 expression was induced by low temperature and mechanical damage stress but not by dehydration stress. The results demonstrate that CsCCD4 catalyzes the production of ß-ionone in the tea plant and provide insight into its formation mechanism during the withering process.


Assuntos
Camellia sinensis/enzimologia , Carotenoides/metabolismo , Dioxigenases/metabolismo , Norisoprenoides/metabolismo , Proteínas de Plantas/metabolismo , Sequência de Aminoácidos , Biocatálise , Camellia sinensis/química , Camellia sinensis/genética , Camellia sinensis/metabolismo , Dioxigenases/genética , Manipulação de Alimentos , Espectrometria de Massas , Filogenia , Folhas de Planta/química , Folhas de Planta/enzimologia , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Plantas/classificação , Plantas/enzimologia , Plantas/genética , Alinhamento de Sequência
11.
Environ Pollut ; 258: 113705, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31864075

RESUMO

Heavy metal accumulation in agricultural land causes crop production losses worldwide. Metal homeostasis within cells is tightly regulated. However, homeostasis breakdown leads to accumulation of reactive oxygen species (ROS). Overall plant fitness under stressful environment is determined by coordination between roots and shoots. But little is known about organ specific responses to heavy metals, whether it depends on the metal category (redox or non-redox reactive) and if these responses are associated with heavy metal accumulation in each organ or there are driven by other signals. Maize seedlings were subjected to sub-lethal concentrations of four metals (Zn, Ni, Cd and Cu) individually, and were quantified for growth, ABA level, and redox alterations in roots, mature leaves (L1,2) and young leaves (L3,4) at 14 and 21 days after sowing (DAS). The treatments caused significant increase in endogenous metal levels in all organs but to different degrees, where roots showed the highest levels. Biomass was significantly reduced under heavy metal stress. Although old leaves accumulated less heavy metal content than root, the reduction in their biomass (FW) was more pronounced. Metal exposure triggered ABA accumulation and stomatal closure mainly in older leaves, which consequently reduced photosynthesis. Heavy metals induced oxidative stress in the maize organs, but to different degrees. Tocopherols, polyphenols and flavonoids increased specifically in the shoot under Zn, Ni and Cu, while under Cd treatment they played a minor role. Under Cu and Cd stress, superoxide dismutase (SOD) and dehydroascorbate reductase (DHAR) activities were induced in the roots, however ascorbate peroxidase (APX) activity was only increased in the older leaves. Overall, it can be concluded that root and shoot organs specific responses to heavy metal toxicity are not only associated with heavy metal accumulation and they are specialized at the level of antioxidants to cope with.


Assuntos
Antioxidantes/metabolismo , Metais Pesados/toxicidade , Estresse Oxidativo , Zea mays/efeitos dos fármacos , Zea mays/enzimologia , Peróxido de Hidrogênio , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/enzimologia , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/enzimologia , Brotos de Planta/efeitos dos fármacos , Brotos de Planta/enzimologia
12.
BMC Plant Biol ; 19(1): 530, 2019 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-31783788

RESUMO

BACKGROUND: Cell wall degrading enzymes (CWDEs) induce plant immune responses and E3 ubiquitin ligases are known to play important roles in regulating plant defenses. Expression of the rice E3 ubiquitin ligase, OsPUB41, is enhanced upon treatment of leaves with Xanthomonas oryzae pv. oryzae (Xoo) secreted CWDEs such as Cellulase and Lipase/Esterase. However, it is not reported to have a role in elicitation of immune responses. RESULTS: Expression of the rice E3 ubiquitin ligase, OsPUB41, is induced when rice leaves are treated with either CWDEs, pathogen associated molecular patterns (PAMPs), damage associated molecular patterns (DAMPs) or pathogens. Overexpression of OsPUB41 leads to induction of callose deposition, enhanced tolerance to Xoo and Rhizoctonia solani infection in rice and Arabidopsis respectively. In rice, transient overexpression of OsPUB41 leads to enhanced expression of PR genes and SA as well as JA biosynthetic and response genes. However, in Arabidopsis, ectopic expression of OsPUB41 results in upregulation of only JA biosynthetic and response genes. Transient overexpression of either of the two biochemically inactive mutants (OsPUB41C40A and OsPUB41V51R) of OsPUB41 in rice and stable transgenics in Arabidopsis ectopically expressing OsPUB41C40A failed to elicit immune responses. This indicates that the E3 ligase activity of OsPUB41 protein is essential for induction of plant defense responses. CONCLUSION: The results presented here suggest that OsPUB41 is possibly involved in elicitation of CWDE triggered immune responses in rice.


Assuntos
Arabidopsis/genética , Regulação da Expressão Gênica de Plantas/imunologia , Oryza/genética , Imunidade Vegetal/genética , Proteínas de Plantas/genética , Ubiquitina-Proteína Ligases/genética , Xanthomonas/fisiologia , Arabidopsis/imunologia , Parede Celular/imunologia , Oryza/imunologia , Folhas de Planta/enzimologia , Folhas de Planta/microbiologia , Proteínas de Plantas/imunologia , Ubiquitina-Proteína Ligases/imunologia , Xanthomonas/enzimologia
13.
Biomolecules ; 10(1)2019 12 20.
Artigo em Inglês | MEDLINE | ID: mdl-31877655

RESUMO

A panel of ethane-methyl-sulfonate-mutagenized japonica rice lines was grown in the presence of salinity in order to identify genes required for the expression of salinity tolerance. A highly nontolerant selection proved to harbor a mutation in FLN2, a gene which encodes fructokinase-like protein2. Exposure of wild-type rice to salinity up-regulated FLN2, while a CRISPR/Cas9-generated FLN2 knockout line was hypersensitive to the stress. Both ribulose 1,5-bisphosphate carboxylase/oxygenase activity and the abundance of the transcript generated by a number of genes encoding components of sucrose synthesis were lower in the knockout line than in wild-type plants' leaves, while the sucrose contents of the leaf and root were, respectively, markedly increased and decreased. That sugar partitioning to the roots was impaired in FLN2 knockout plants was confirmed by the observation that several genes involved in carbon transport were down-regulated in both the leaf and in the leaf sheath. The levels of sucrose synthase, acid invertase, and neutral invertase activity were distinctly lower in the knockout plants' roots than in those of wild-type plants, particularly when the plants were exposed to salinity stress. The compromised salinity tolerance exhibited by the FLN2 knockout plants was likely a consequence of an inadequate supply of the assimilate required to support growth, a problem which was rectifiable by providing an exogenous supply of sucrose. The conclusion was that FLN2, on account of its influence over sugar metabolism, is important in the context of seedling growth and the rice plant's response to salinity stress.


Assuntos
Frutoquinases/metabolismo , Oryza/enzimologia , Proteínas de Plantas/metabolismo , Metabolismo dos Carboidratos , Frutoquinases/genética , Regulação da Expressão Gênica de Plantas , Oryza/genética , Oryza/crescimento & desenvolvimento , Oryza/metabolismo , Folhas de Planta/enzimologia , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Salinidade , Cloreto de Sódio/metabolismo
14.
IET Syst Biol ; 13(6): 327-332, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31778129

RESUMO

The emission of chlorophyll fluorescence (ChlF) from photosystem II (PSII) of plant leaves the couple with photoelectron transduction cascades in photosynthetic reactions and can be used to probe photosynthetic efficiency and plant physiology. Because of population increase, food shortages, and global warming, it is becoming more and more urgent to enhance plant photosynthesis efficiency by controlling plant growth rate. An effective model structure is essential for plant control strategy development. However, there is a lack of reporting on modelling and simulation of PSII activities under the interaction of both illumination light intensities and temperatures, which are the two important controllable factors affecting, plant growth, especially for a greenhouse. In this work, the authors extended their work on modelling photosynthetic activities as affected by light and temperature to cover both the interaction effects of illumination light intensities and temperature on ChlF emission. Experiments on ChlF were performed under different light intensities and temperatures and used to validate the developed model structure. The average relative error between experimental data and model fitting is <0.3%, which shows the effectiveness of the developed model structure. Simulations were performed to show the interaction effect of light and temperature effects on photosynthetic activities.


Assuntos
Fluorescência , Luz , Modelos Biológicos , Complexo de Proteína do Fotossistema II/metabolismo , Folhas de Planta/metabolismo , Plantas/metabolismo , Temperatura , Relação Dose-Resposta à Radiação , Folhas de Planta/enzimologia , Folhas de Planta/efeitos da radiação , Plantas/enzimologia , Plantas/efeitos da radiação
15.
Postepy Biochem ; 65(2): 128-134, 2019 06 06.
Artigo em Polonês | MEDLINE | ID: mdl-31642651

RESUMO

During leaf senescence and fruit ripening chlorophyll is broken down into nonfluorescent catabolites (NCCs). The chlorophyll degradation pathway includes a series of biochemical transformations ocurring sequentially in chloroplasts, cytosol and vacuoles. The path begins with enzymatic reduction of chlorophyll b to chlorophyll a. Next, the specific dechelatase and esterase remove the magnesium atom and the phytol chain resulting in the formation of pheophorbide a. In the next step, the porphyrin macroring is opened by pheophorbide a oxygenase and red catabolite reductase. The product of this transformation is an early fluorescent catabolite (pFCC), which after hydroxylation and species-specific modifications is imported into the vacuole. In acidic medium of the vacuole pFCC undergo isomerization to their respective colorless NCCs, which are final chlorophyll degradation products in higher plants. There are still no answers to a number of questions about the fate and significance of millions tons of chlorophyll catabolites released annually in the aquatic environment as a result of cellular senescence and death of phytoplankton. A few reports indicate that algae and cyanobacteria may metabolize their photosynthetic pigments in a similar way as higher plants do, however, the course of chlorophyll breakdown in these organisms has not been yet elucidated.


Assuntos
Clorofila/metabolismo , Células Vegetais/metabolismo , Oxirredutases/metabolismo , Células Vegetais/enzimologia , Folhas de Planta/enzimologia , Folhas de Planta/metabolismo
16.
J Agric Food Chem ; 67(49): 13367-13392, 2019 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-31591878

RESUMO

Green leaf volatiles (GLVs) are mainly C6- and in rare cases also C9-aldehydes, -alcohols, and -esters, which are released by plants in response to biotic or abiotic stresses. These compounds are named for their characteristic smell reminiscent of freshly mowed grass. This review focuses on GLVs and the two major pathway enzymes responsible for their formation: lipoxygenases (LOXs) and fatty acid hydroperoxide lyases (HPLs). LOXs catalyze the peroxidation of unsaturated fatty acids, such as linoleic and α-linolenic acids. Hydroperoxy fatty acids are further converted by HPLs into aldehydes and oxo-acids. In many industrial applications, plant extracts have been used as LOX and HPL sources. However, these processes are limited by low enzyme concentration, stability, and specificity. Alternatively, recombinant enzymes can be used as biocatalysts for GLV synthesis. The increasing number of well-characterized enzymes efficiently expressed by microbial hosts will foster the development of innovative biocatalytic processes for GLV production.


Assuntos
Aldeído Liases/química , Sistema Enzimático do Citocromo P-450/química , Aromatizantes/química , Lipoxigenases/química , Folhas de Planta/enzimologia , Proteínas de Plantas/química , Compostos Orgânicos Voláteis/química , Aldeído Liases/genética , Aldeído Liases/metabolismo , Biocatálise , Sistema Enzimático do Citocromo P-450/genética , Sistema Enzimático do Citocromo P-450/metabolismo , Aromatizantes/metabolismo , Lipoxigenases/genética , Lipoxigenases/metabolismo , Folhas de Planta/química , Folhas de Planta/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Compostos Orgânicos Voláteis/metabolismo
17.
Plant Sci ; 287: 110188, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31481229

RESUMO

9-cis-epoxycarotenoid dioxygenase (NCED) is a rate-limiting enzyme for abscisic acid (ABA) biosynthesis. However, the molecular mechanisms of NCED5 that modulate plant development and abiotic stress tolerance are still unclear, particular in rice. Here, we demonstrate that a rice NCED gene, OsNCED5, was expressed in all tissues we tested, and was induced by exposure to salt stress, water stress, and darkness. Mutational analysis showed that nced5 mutants reduced ABA level and decreased tolerance to salt and water stress and delayed leaf senescence. However, OsNCED5 overexpression increased ABA level, enhanced tolerance to the stresses, and accelerated leaf senescence. Transcript analysis showed that OsNCED5 regulated ABA-dependent abiotic stress and senescence-related gene expression. Additionally, ectopic expression of OsNCED5 tested in Arabidopsis thaliana altered plant size and leaf morphology and delayed seed germination and flowering time. Thus, OsNCED5 may regulate plant development and stress resistance through control of ABA biosynthesis. These findings contribute to our understanding of the molecular mechanisms by which NCED regulates plant development and responses to abiotic stress in different crop species.


Assuntos
Dioxigenases/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Oryza/enzimologia , Proteínas de Plantas/metabolismo , Arabidopsis/genética , Arabidopsis/fisiologia , Desidratação , Dioxigenases/genética , Oryza/genética , Oryza/fisiologia , Folhas de Planta/enzimologia , Folhas de Planta/genética , Folhas de Planta/fisiologia , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Estresse Fisiológico , Água/metabolismo
18.
Genome ; 62(12): 793-805, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31491334

RESUMO

Acer pictum subsp. mono is a colored leaf tree with vital ornamental and economic value. However, insufficient color change and early leaf fall in cities restrict its ornamental value. In this research, green and red leaves from wild A. p. subsp. mono were collected to study the regulatory mechanisms of leaf color change. Through the determination of plant physiological indexes, we found that the photosynthetic pigment content in red leaves decreased significantly compared with green leaves, while the anthocyanin content and antioxidant activity increased significantly compared with green leaves during the leaf color change process. Using transcriptome sequencing, we found more than 5500 differentially expressed genes, most of which were up-regulated. Many of the differentially expressed genes are involved in the anthocyanin metabolic pathway. The expression patterns of 15 key genes were investigated by quantitative real-time polymerase chain reaction. Among these genes, AmDFR and PAL1 are significant genes involved in the anthocyanin metabolic pathway, and CIPKs2, CIPKs6, CMLs1, CMLs38, AmGST1, AmGST2, GPX3, CBF, AmAPX, AmSOD, POD5, AmGR, and PSBY might be stress response genes that indirectly regulated the anthocyanin accumulation. The results showed that these genes play vital roles in the leaf color change of A. p. subsp. mono. This research will be helpful in further study of the molecular regulatory mechanisms of leaf color change and for the improvement of colored leaf plants.


Assuntos
Acer/genética , Folhas de Planta/genética , Acer/enzimologia , Acer/metabolismo , Cor , Perfilação da Expressão Gênica , Pigmentos Biológicos/metabolismo , Folhas de Planta/enzimologia , Folhas de Planta/metabolismo , Análise de Sequência de RNA , Superóxido Dismutase/metabolismo
19.
J Biochem ; 166(5): 441-448, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31504617

RESUMO

Glycosylinositol phosphoceramide (GIPC) is the most abundant sphingolipid in plants and fungi. Recently, we detected GIPC-specific phospholipase D (GIPC-PLD) activity in plants. Here, we found that GIPC-PLD activity in young cabbage leaves catalyzes transphosphatidylation. The available alcohol for this reaction is a primary alcohol with a chain length below C4. Neither secondary alcohol, tertiary alcohol, choline, serine nor glycerol serves as an acceptor for transphosphatidylation of GIPC-PLD. We also found that cabbage GIPC-PLD prefers GIPC containing two sugars. Neither inositol phosphoceramide, mannosylinositol phosphoceramide nor GIPC with three sugar chains served as substrate. GIPC-PLD will become a useful catalyst for modification of polar head group of sphingophospholipid.


Assuntos
Biocatálise , Brassica/enzimologia , Ceramidas/metabolismo , Inositol/metabolismo , Fosfatidilcolinas/metabolismo , Fosfolipase D/metabolismo , Folhas de Planta/enzimologia , Brassica/química , Ceramidas/química , Inositol/análogos & derivados , Inositol/química , Estrutura Molecular , Fosfatidilcolinas/química , Fosfolipase D/química , Folhas de Planta/química
20.
J Appl Microbiol ; 127(6): 1790-1800, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31509316

RESUMO

AIMS: Ratoon stunting disease caused by Leifsonia xyli subsp. xyli (Lxx) is a bacterial disease that has plagued sugarcane-planting countries for a long time. This study mainly analysed Lxx localization and its effects on sugarcane leaf. METHODS AND RESULTS: Badila were inocultated by bacteria of Lxx. It was noted that the number of Lxx cells were rapidly enriched in sugarcane leaves from the 150th to the 210th days of post inoculation (dpi). Lxx infection disrupted the integrity of vascular bundle sheath cells (BSC) in the 'Kranz anatomy' of leaves, resulting in irregular accumulation of starch in vascular BSC of leaves. In situ PCR showed that the Lxx localized in the xylem vessels, mesophyll cell (MC) and BSC as described before in sugarcane leaf, a new niche within the host tissues in the phloem of sugarcane stem. The gene expression and activities of phosphoenolpyruvate carboxylase (PEPC), pyruvate, orthophosphate dikinase (PPDK) and NADP-malic enzyme (NADP-ME) enzymes were lower in Lxx-inoculated sugarcane plants as compared to the MI group. CONCLUSION: Lxx infection not only disrupted the structure of vascular BSC in the C4 'Kranz anatomy' of sugarcane leaves, but also affected the activities and gene expression of the key enzymes PEPC, PPDK and NADP-ME in the C4 cycle of sugarcane suggesting a reduction in CO2 fixation. SIGNIFICANCE AND IMPACT OF THE STUDY: The effect of Leifsonia xyli subsp. xyli (Lxx) infection on the photosynthetic physiology of sugarcane is currently limited to the evaluation of photosynthetic parameters. This study assessed the impact of Lxx infection on the mechanism of C4 cycle CO2 fixation and to accompanying plant anatomy.


Assuntos
Actinomycetales/fisiologia , Enzimas/metabolismo , Fotossíntese , Doenças das Plantas/microbiologia , Saccharum/enzimologia , Saccharum/microbiologia , Regulação da Expressão Gênica de Plantas , Fotossíntese/genética , Folhas de Planta/enzimologia , Folhas de Planta/microbiologia , Feixe Vascular de Plantas/enzimologia , Feixe Vascular de Plantas/microbiologia , Amido/metabolismo
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