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1.
Plant Mol Biol ; 101(3): 315-323, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31392474

RESUMO

KEY MESSAGE: Pre-treatment of soybean seedlings with 200 µM salicylic acid before fungal inoculation significantly alleviated disease resistance in soybean seedlings against Fusarium solani infection. Sudden death syndrome of soybean is largely caused by Fusarium solani (F. solani). Salicylic acid (SA) has been reported to induce resistance in plants against many pathogens. However, the effect of exogenous SA application on F. solani infection of soybean is less reported. This study investigated the effect of foliar application of SA on soybean seedlings before F. solani infection. Seedlings were sprayed with 200 µM SA and inoculated with F. solani after 24 h of last SA application. After 3 days post-inoculation, seedlings treated with 200 µM SA showed significantly fewer disease symptoms with increased endogenous SA level, SA marker genes expression and antioxidant activities in the SA-treated seedlings more than the untreated control seedlings. Furthermore, the decrease in hydrogen peroxide (H2O2) and malondialdehyde (MDA) levels was observed in the SA-treated plants as compared to the untreated plants. Analysis of the effect of SA application on F. solani showed that the mycelia growth of F. solani was not affected by SA treatment. Further investigation in this study revealed a decreased in F. solani biomass content in the SA treated seedlings. Results from the present study show that pre-treatment of 200 µM SA can induce resistance of soybean seedlings against F. solani infection.


Assuntos
Resistência à Doença/efeitos dos fármacos , Fusarium/patogenicidade , Doenças das Plantas/microbiologia , Ácido Salicílico/farmacologia , Soja/microbiologia , Regulação da Expressão Gênica de Plantas , Peróxido de Hidrogênio/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/microbiologia , Plântula/efeitos dos fármacos , Plântula/microbiologia , Soja/efeitos dos fármacos
2.
Plant Mol Biol ; 101(1-2): 149-162, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31267255

RESUMO

KEY MESSAGE: Here we describe that the regulation of MdWRKY31 on MdHIR4 in transcription and translation levels associated with disease in apple. The phytohormone salicylic acid (SA) is a main factor in apple (Malus domestica) production due to its function in disease resistance. WRKY transcription factors play a vital role in response to stress. An RNA-seq analysis was conducted with 'Royal Gala' seedlings treated with SA to identify the WRKY regulatory mechanism of disease resistance in apple. The analysis indicated that MdWRKY31 was induced. A quantitative real-time polymerase chain reaction (qPCR) analysis demonstrated that the expression of MdWRKY31 was induced by SA and flg22. Ectopic expression of MdWRKY31 in Arabidopsis and Nicotiana benthamiana increased the resistance to flg22 and Pseudomonas syringae tomato (Pst DC3000). A yeast two-hybrid screen was conducted to further analyze the function of MdWRKY31. As a result, hypersensitive-induced reaction (HIR) protein MdHIR4 interacted with MdWRKY31. Biomolecular fluorescence complementation, yeast two-hybrid, and pull-down assays demonstrated the interaction. In our previous study, MdHIR4 conferred decreased resistance to Botryosphaeria dothidea (B. dothidea). A viral vector-based transformation assay indicated that MdWRKY31 evaluated the transcription of SA-related genes, including MdPR1, MdPR5, and MdNPR1 in an MdHIR4-dependent way. A GUS analysis demonstrated that the w-box, particularly w-box2, of the MdHIR4 promoter played a major role in the responses to SA and B. dothidea. Electrophoretic mobility shift assays, yeast one-hybrid assay, and chromatin immunoprecipitation-qPCR demonstrated that MdWRKY31 directly bound to the w-box2 motif in the MdHIR4 promoter. GUS staining activity and a protein intensity analysis further showed that MdWRKY31 repressed MdHIR4 expression. Taken together, our findings reveal that MdWRKY31 regulated plant resistance to B. dothidea through the SA signaling pathway by interacting with MdHIR4.


Assuntos
Resistência à Doença , Malus/genética , Doenças das Plantas/imunologia , Reguladores de Crescimento de Planta/farmacologia , Proteínas de Plantas/metabolismo , Ácido Salicílico/farmacologia , Arabidopsis/genética , Arabidopsis/imunologia , Arabidopsis/microbiologia , Ascomicetos/fisiologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Frutas/genética , Frutas/imunologia , Frutas/microbiologia , Regulação da Expressão Gênica de Plantas , Genes Reporter , Malus/imunologia , Malus/microbiologia , Doenças das Plantas/microbiologia , Proteínas de Plantas/genética , Regiões Promotoras Genéticas/genética , Pseudomonas syringae/fisiologia , Plântula/genética , Plântula/imunologia , Plântula/microbiologia , Transdução de Sinais , Tabaco/genética , Tabaco/imunologia , Tabaco/microbiologia , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Técnicas do Sistema de Duplo-Híbrido
3.
Plant Mol Biol ; 101(1-2): 95-112, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31236845

RESUMO

KEY MESSAGE: Sorghum glycine rich proline rich protein (SbGPRP1) exhibit antimicrobial properties and play a crucial role during biotic stress condition. Several proteins in plants build up the innate immune response system in plants which get triggered during the occurrence of biotic stress. Here we report the functional characterization of a glycine-rich proline-rich protein (SbGPRP1) from Sorghum which was previously demonstrated to be involved in abiotic stresses. Expression studies carried out with SbGPRP1 showed induced expression upon application of phytohormones like salicylic acid which might be the key in fine-tuning the expression level. Upon challenging the Sorghum plants with a compatible pathogen the SbGprp1 transcript was found to be upregulated. SbGPRP1 encodes a 197 amino acid polypeptide which was bacterially-expressed and purified for in vitro assays. Gram-positive bacteria like Bacillus and phytopathogen Rhodococcus fascians showed inhibited growth in the presence of the protein. The NPN assay, electrolytic leakage and SEM analysis showed membrane damage in bacterial cells. Ectopic expression of SbGPRP1 in tobacco plants led to enhanced tolerance towards infection caused by R. fascians. Though the N-terminal part of the protein showed disorderness the C-terminal end was quite capable of forming several α-helices which was correlated with CD spectroscopic analysis. Here, we have tried to determine the structural model for the protein and predicted the association of antimicrobial activity with the C-terminal region of the protein.


Assuntos
Anti-Infecciosos/metabolismo , Doenças das Plantas/imunologia , Reguladores de Crescimento de Planta/farmacologia , Proteínas de Plantas/metabolismo , Ácido Salicílico/farmacologia , Sorghum/genética , Bacillus/efeitos dos fármacos , Expressão Ectópica do Gene , Glicina/metabolismo , Filogenia , Doenças das Plantas/microbiologia , Proteínas de Plantas/genética , Prolina/metabolismo , Rhodococcus/efeitos dos fármacos , Sorghum/imunologia , Sorghum/metabolismo , Sorghum/microbiologia , Estresse Fisiológico , Tabaco/genética , Tabaco/imunologia , Tabaco/metabolismo , Tabaco/microbiologia
4.
Plant Mol Biol ; 100(6): 659-674, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31187392

RESUMO

KEY MESSAGE: Oxalotrophic Stenotrophomonas isolated from tomato rhizosphere are able to protect plants against oxalate-producing pathogens by a combination of actions including induction of plant defence signalling callose deposition and the strengthening of plant cell walls and probably the degradation of oxalic acid. Oxalic acid plays a pivotal role in the virulence of the necrotrophic fungi Botrytis cinerea and Sclerotinia sclerotiorum. In this work, we isolated two oxalotrophic strains (OxA and OxB) belonging to the bacterial genus Stenotrophomonas from the rhizosphere of tomato plants. Both strains were capable to colonise endophytically Arabidopsis plants and protect them from the damage caused by high doses of oxalic acid. Furthermore, OxA and OxB protected Arabidopsis from S. sclerotiorum and B. cinerea infections. Bacterial inoculation induced the production of phenolic compounds and the expression of PR-1. Besides, both isolates exerted a protective effect against fungal pathogens in Arabidopsis mutants affected in the synthesis pathway of salicylic acid (sid2-2) and jasmonate perception (coi1). Callose deposition induced by OxA and OxB was required for protection against phytopathogens. Moreover, B. cinerea and S. sclerotiorum mycelial growth was reduced in culture media containing cell wall polysaccharides from leaves inoculated with each bacterial strain. These findings suggest that cell walls from Arabidopsis leaves colonised by these bacteria would be less susceptible to pathogen attack. Our results indicate that these oxalotrophic bacteria can protect plants against oxalate-producing pathogens by a combination of actions and show their potential for use as biological control agents against fungal diseases.


Assuntos
Fungos/patogenicidade , Lycopersicon esculentum/microbiologia , Oxalatos/metabolismo , Stenotrophomonas/fisiologia , Arabidopsis/metabolismo , Botrytis/metabolismo , Botrytis/patogenicidade , Parede Celular/metabolismo , Ciclopentanos/química , Fungos/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Ácido Oxálico/metabolismo , Oxilipinas/química , Filogenia , Doenças das Plantas/microbiologia , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Polissacarídeos/metabolismo , Ácido Salicílico/farmacologia , Transdução de Sinais , Stenotrophomonas/isolamento & purificação
5.
Plant Physiol Biochem ; 141: 315-324, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31207492

RESUMO

Different SA concentrations (10, 100 and 1000 µM) were applied in young olive trees (Olea europaea L.) subjected to drought and rewatering. Plants treated with 10 µM exhibited a close behavior to SA-starved plants. Although both 100 and 1000 µM improved the balance between ROS production and scavenging, 100 µM was more efficient. During drought, 100 µM improved ROS detoxification and scavenging by the maintenance or overaccumulation of soluble proteins. During recovery, soluble proteins return to well-watered values and increased the investment in non-enzymatic antioxidants. 100 µM was also the most effective in plant ionome regulation, improving macro and micronutrients uptake, namely P, Fe, Mn and Zn, and changing mineral allocation patterns. Therefore, 100 µM also countered the drought-induced decline in total plant biomass accumulation. The application of suitable SA concentrations is an efficient tool to improve cellular homeostasis and growth of plants subjected to recurrent drought episodes.


Assuntos
Secas , Íons/metabolismo , Olea/metabolismo , Oxirredução , Folhas de Planta/metabolismo , Ácido Salicílico/farmacologia , Antioxidantes/química , Biomassa , Minerais/química , Nutrientes/química , Estresse Oxidativo , Fotossíntese/efeitos dos fármacos , Raízes de Plantas/metabolismo , Portugal , Espécies Reativas de Oxigênio/metabolismo , Água/metabolismo
6.
J Sci Food Agric ; 99(13): 5946-5952, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31206683

RESUMO

BACKGROUND: Grape berries produce significant amounts of phenolic compounds. These are an essential qualitative factor due to their nutritional value and effect on berry color and texture. Salicylic acid (SA) and its derivatives usually lead to enhancement of phenolic content in plant tissues. The present study was conducted to evaluate the effect of different levels of SA (0.0, 50.0, 100.0, and 200.0 mM) on the production of phenolic compounds and the derivatives (anthocyanin and flavonoid) in the grape berries, with emphasis on malvidin-3-O-ß glucoside as a regular anthocyanin in red grapes. RESULT: The results showed that total phenolics content were significantly enhanced in SA-treated (100.0 and 200.0 mM) berries compared to untreated ones. Salicylic acid treatment at all concentrations considerably improved the anthocyanin content in the berries and, compared with untreated berries, the accumulation of malvidin-3-O-ß glucoside was higher in SA-treated fruits. In particular, the 200.0 mM concentration caused approximately two times more malvidin-3-O-ß glucoside than the control. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging capacity of the fruits treated with SA were significantly higher than those of the untreated berries. The activity of phenylalanine ammonia-lyase (PAL) in SA treated fruits significantly increased as compared with the untreated clusters. CONCLUSION: A general evaluation of the current results leads us to the conclusion that SA is a suitable and recommendable treatment for improving and increasing the phenolic and antioxidant capacity of grape berries. Spraying grape berries at pre-véraison stage with SA could therefore be a convenient strategy to increase quality and nutritional value of grape berries considerably. © 2019 Society of Chemical Industry.


Assuntos
Antocianinas/química , Frutas/química , Extratos Vegetais/química , Ácido Salicílico/farmacologia , Vitis/química , Antioxidantes/metabolismo , Cor , Frutas/efeitos dos fármacos , Fenóis/química , Fenilalanina Amônia-Liase/genética , Fenilalanina Amônia-Liase/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Vitis/efeitos dos fármacos , Vitis/genética
7.
Molecules ; 24(9)2019 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-31083517

RESUMO

Salicylic acid (SA) has for a long time been used to treat various skin disorders due to its anti-inflammatory, bacteriostatic, and antifungal properties. In the present work, mesoporous magnesium carbonate (MMC), a promising drug carrier, was modified with 3-aminopropyl-triethoxysilane to enable loading of SA. The amine modified MMC (aMMC) was successfully loaded with 8 wt.% of SA via a solvent evaporation method. SA was later completely released from the carrier in less than 15 min. Furthermore, the cytotoxicity of the functionalized material was evaluated. aMMC was found to be non-toxic for human dermal fibroblast cells with particle concentration of up to 1000 µg/mL when exposed for 48 h. The presented results form the basis of future development of aMMC as a potential carrier for SA in dermatological applications.


Assuntos
Aminas/química , Portadores de Fármacos/química , Magnésio/química , Ácido Salicílico/farmacologia , Administração Tópica , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Composição de Medicamentos , Sistemas de Liberação de Medicamentos/métodos , Liberação Controlada de Fármacos , Humanos , Microscopia Eletrônica de Varredura , Porosidade , Ácido Salicílico/administração & dosagem , Espectroscopia de Infravermelho com Transformada de Fourier
8.
Ecotoxicol Environ Saf ; 180: 575-587, 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31129436

RESUMO

The present study identified inverse relationships between nickel (Ni) levels and growth, photosynthesis and physio-biochemical attributes, but increasing levels of Ni stress enhanced methylglyoxal, electrolyte leakage, hydrogen peroxide, and lipid peroxidation content. Exogenous application of salicylic acid (SA) (10-5 M) ameliorated the ill-effects of Ni by restoring growth, photosynthesis and physio-biochemical attributes and increasing the activities of enzymes associated with antioxidant systems, especially the ascorbate-glutathione (AsA-GSH) cycle and glyoxalase system. In addition, SA application to Ni-stressed plants had an additive effect on the activities of the ascorbate and glutathione pools, and the AsA-GSH cycle enzymes (ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, glutathione reductase), superoxide dismutase, catalase, glutathione S-transferase, and osmolyte biosynthesis). This trend also follows in glyoxalase system viz. glyoxalase I and glyoxalase II enzymes. Nevertheless, exogenous SA supplementation restored mineral nutrient contents. Principal component analysis showed that growth, photosynthesis, and mineral nutrient parameters were positively correlated with each other and negatively correlated with antioxidant enzymes and oxidative stress biomarkers. Hence, SA is an alternative compound with potential application in the phytoremediation of Ni.


Assuntos
Níquel/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Ácido Salicílico/farmacologia , Antioxidantes/metabolismo , Ácido Ascórbico/metabolismo , Glutationa/metabolismo , Lactoilglutationa Liase/metabolismo , Peroxidação de Lipídeos , Mostardeira/efeitos dos fármacos , Mostardeira/enzimologia , Mostardeira/metabolismo , Fotossíntese/efeitos dos fármacos , Aldeído Pirúvico/metabolismo , Tioléster Hidrolases/metabolismo , Regulação para Cima/efeitos dos fármacos
9.
Molecules ; 24(8)2019 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-30991767

RESUMO

This study was carried out to evaluate genetic diversity, phenolic compound composition, and biological activity of Setaria italica L. collected from different parts of South Korea. Antioxidant potential of seeds was estimated by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay, and antimicrobial activity was determined by evaluating the minimum inhibitory concentration (MIC). Eight phenolic acids and 3 flavonoids were identified and quantified, among which myricetin and salicylic acid were the most dominant phytochemical compounds detected in the majority of accessions. The antioxidant potential of the leaf extracts of all the accessions was significantly higher (ranging from 32.33 ± 1.53 µg mL-¹ in SI-03 to 87.87 ± 1.63 µg mL-¹) in SI-10 than that of the root, stem, or seeds. Among the 15 accessions, methanolic extracts of the SI-15 accession strongly suppressed the growth of Escherichia coli (250 µg mL-¹). Accessions SI-14 and SI-15 showed positive antimicrobial activity against all gram-positive bacteria. Interestingly, extracts of all accessions were more sensitive towards E. coli and Staphylococcus aureus, with MICs ranging from 250 to 1000 µg mL-¹. Three phenolic acids, namely chlorogenic acid, catechin, caffeic acid, naringin, hesperetin, and myricetin, were found to be moderately positively correlated with antioxidant activities. A wide range of diversity was observed in morphological traits, namely plant height (99.33 to 201.33 cm), culm length (67.10 to 160.00 cm), spike length (12.80 to 24.00 cm), 1000 seeds weight 1.44 to 2.91 g), bloom beginning (93.67 to 128.00 days), and full bloom (99.67 to 135 days). A dendogram generated from unweighted pair group method with arithmetic mean clustering (UPGMA) cluster analysis based on the morphological traits and inter simple sequence repeat (ISSR) marker data revealed three major groups. However, no clear correlation between these two different approaches was found. The average Shannon's information index value (I) was 0.492, and it ranged from 0 to 0.693. The average expected heterozygosity (He) was 0.335, and it ranged from 0 to 0.499. The substantial variation in the morphological traits, bioactive properties, and genetic diversity among the accessions may provide useful information for breeding programs attempting to obtain S. italica with improved bioactive properties.


Assuntos
Antibacterianos , Escherichia coli/crescimento & desenvolvimento , Compostos Fitoquímicos , Extratos Vegetais , Setaria (Planta)/química , Antibacterianos/química , Antibacterianos/farmacologia , Flavonoides/química , Flavonoides/farmacologia , Compostos Fitoquímicos/química , Compostos Fitoquímicos/farmacologia , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Ácido Salicílico/farmacologia
10.
Ecotoxicol Environ Saf ; 178: 66-78, 2019 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-30999182

RESUMO

Salt stress disturbs redox homeostasis by perturbing equilibrium between generation and removal of reactive oxygen species (ROS), which alters the normal metabolism of plants through membrane damage, lipid peroxidation and denaturation of proteins. Salicylic acid (SA) seed priming and arbuscular mycorrhizal (AM) fungi impart salt tolerance in legumes by maintaining redox balance. The present investigation focused on the relative and combined applications of SA and Rhizoglomus intraradices in scavenging ROS in Cicer arietinum L. (chickpea) genotypes (salt tolerant-PBG 5, relatively sensitive-BG 256) subjected to salt stress. Despite the enhanced antioxidant mechanisms under salt stress, ROS (superoxide, O2- and hydrogen peroxide, H2O2) accumulation increased significantly and induced lipid peroxidation and lipoxygenase (LOX) activities, which disrupted membrane stability, more in BG 256 than PBG 5. Salt stress also caused redox imbalance by lowering ascorbate/dehydroascorbate (ASA/DHA) and reduced glutathione/oxidized glutathione (GSH/GSSG) ratios, indicating that redox-homeostasis was crucial for salt-tolerance. Exogenous SA was more promising in reducing ROS-generation and lipid-peroxidation, which provided higher membrane stability as compared to AM inoculation. Although, the enzymatic antioxidants were more active in SA treated plants, yet, AM inoculation outperformed in increasing reformative enzyme activities of Foyer-Halliwell-Asada cycle, which resulted in higher plant biomass in a genotype-dependent manner. SA increased AM root colonization and provided functional complementarity to R. intraradices and thereby strengthening antioxidant defense mechanisms through their cumulative contribution. The study suggested the use of +SA+AM as an eco-friendly tool in imparting salt tolerance in chickpea genotypes subjected to long-term salinity.


Assuntos
Antioxidantes/metabolismo , Cicer/metabolismo , Glomeromycota/metabolismo , Micorrizas/metabolismo , Ácido Salicílico/farmacologia , Estresse Salino , Ácido Ascórbico/metabolismo , Cicer/efeitos dos fármacos , Cicer/microbiologia , Genótipo , Oxirredução , Estresse Oxidativo/efeitos dos fármacos , Ácido Salicílico/metabolismo , Tolerância ao Sal , Sementes/efeitos dos fármacos , Sementes/metabolismo , Sementes/microbiologia , Simbiose
11.
BMC Plant Biol ; 19(1): 115, 2019 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-30922222

RESUMO

BACKGROUND: It is well known that aromatic essential oils extracted from the heartwood of Santalum album L. have wide economic value. However, little is known about the role of terpenoids in response to various adverse environmental stresses as other plants do in the form of signals during plant-environment interactions. RESULTS: In this study, trace amounts of volatiles consisting of α-santalene, epi-ß-santalene, ß-santalene, α-santalol, ß-santalol, (E)-α-bergamotene, (E)-ß-farnesene and ß-bisabolene were found in the leaves of mature S. album trees. We identified more than 40 candidate terpene synthase (TPS) unigenes by mining publicly-available RNA-seq data and characterized the enzymes encoded by three cDNAs: one mono-TPS catalyzes the formation of mostly α-terpineol, and two multifunctional sesqui-TPSs, one of which produces (E)-α-bergamotene and sesquisabinene as major products and another which catalyzes the formation of (E)-ß-farnesene, (E)-nerolidol and (E,E)-farnesol as main products. Metabolite signatures and gene expression studies confirmed that santalol content is closely related with santalene synthase (SaSSY) transcripts in heartwood, which is key enzyme responsible for santalol biosynthesis. However, the expression of three new SaTPS genes differed significantly from SaSSY in the essential oil-producing heartwood. Increased activities of antioxidant enzymes, superoxide dismutase, catalase, peroxidase and ascorbate peroxidase, were detected in different tissues of S. album plants after applying 1 mM methyl jasmonate (MeJA) and 1 mM salicylic acid (SA), or exposure to 4°C, 38°C and high light intensity. MeJA and SA dramatically induced the expression of SaTPS1 and SaTPS2 in leaves. SaTPS1 to 3 transcripts were differentially activated among different tissues under adverse temperature and light stresses. In contrast, almost all SaSSY transcripts decreased in response to these environmental stresses, unlike SaTPS1 to 3. CONCLUSIONS: Multifunctional enzymes were biochemically characterized, including one chloroplastic mono-TPS and two cytosolic sesqui-TPSs in sandalwood. Our results suggest the ecological importance of these three new SaTPS genes in defensive response to biotic attack and abiotic stresses in S. album.


Assuntos
Alquil e Aril Transferases/genética , Proteínas de Plantas/genética , Santalum/fisiologia , Estresse Fisiológico/genética , Acetatos/farmacologia , Alquil e Aril Transferases/metabolismo , Ciclopentanos/farmacologia , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Luz , Família Multigênica , Oxilipinas/farmacologia , Filogenia , Folhas de Planta/química , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Ácido Salicílico/farmacologia , Santalum/efeitos dos fármacos , Santalum/genética , Temperatura Ambiente , Terpenos/análise , Terpenos/química , Terpenos/metabolismo , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/química
12.
J Biotechnol ; 297: 9-18, 2019 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-30880184

RESUMO

In the present study, we have developed an inter-molecularly shuffled caulimoviral promoter for protein over-expression by placing the Upstream Activation Sequence (UAS) of Figwort Mosaic Virus (FMV; -249 to -54) at the 5'-end of the Cassava Vein Mosaic Virus (CsVMV) promoter fragment 8 (CsVMV8; -215 to +166) to design a hybrid promoter; FUASCsV8CP. The FUASCsV8CP promoter exhibited approximately 2.1 and 2.0 times higher GUS-activities than that obtained from the CaMV35S promoter, in tobacco (Xanthi Brad) protoplasts and in Agroinfiltration assays respectively. Hereto, when FUASCsV8CP was assayed using transgenic tobacco plants (T2- generation), it showed 2.0 times stronger activity than CaMV35S promoter and almost equivalent activity to that of CaMV35S2 promoter. The promoter displayed Salicylic acid (SA) inducibility and hence can also be used for ensuring effective gene expression in plants under constitutive as well as specific inducible conditions. Furthermore, FUASCsV8CP was used to drive the expression of victoviral Vin gene (encoding Victoriocin) transiently in tobacco. The recombinant Victoriocin could be successfully detected by western blotting three days post infiltration. Also, the in vitro Agar-based killing zone assays employing plant-derived Victoriocin-His (obtained from transient expression of Vin) revealed enhanced antifungal activity of Victoriocin against hemi-biotrophic pathogen Phoma exigua Desm. var. exigua.


Assuntos
Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Regiões Promotoras Genéticas , Recombinação Genética/genética , Ácido Salicílico/farmacologia , Pesquisa Médica Translacional , Antifúngicos/farmacologia , Ascomicetos/efeitos dos fármacos , Caulimovirus/genética , Glucuronidase/metabolismo , Testes de Sensibilidade Microbiana , Plantas Geneticamente Modificadas , Tabaco/genética
13.
Phytopathology ; 109(7): 1102-1114, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30880572

RESUMO

Tomato gray mold disease caused by Botrytis cinerea is a serious disease that threatens tomato production around the world. Clonostachys rosea has been used successfully as a biocontrol agent against divergent plant pathogens, including B. cinerea. To understand the signal transduction pathway of C. rosea-induced resistance to tomato gray mold disease, the effects of C. rosea on gray mold tomato leaves along with changes in the activities of three defense enzymes (phenylalanine ammonialyase [PAL], polyphenol oxidase [PPO], and catalase [CAT]), second messengers (nitric oxide [NO], hydrogen peroxide [H2O2], and superoxide anion radical [O2-]), and stress-related genes (mitogen-activated protein kinase [MAPK], WRKY, Lexyl2, and atpA) in four different hormone-deficient (jasmonic acid [JA], ethylene [ET], salicylic acid [SA], and gibberellin) tomato mutants were investigated. The results revealed that C. rosea significantly inhibited the growth of mycelia and spore germination of B. cinerea. Furthermore, it reduced the incidence of gray mold disease, induced higher levels of PAL and PPO, and induced lower levels of CAT activities in tomato leaves. Moreover, it also increased NO, H2O2, and O2- levels and the gene expression levels of WRKY, MAPK, atpA, and Lexyl2. The incidence of gray mold disease in four hormone-deficient mutants was higher than that in the corresponding wild-type tomato plants. Among all of these hormone-deficient tomato mutants, JA had the most significant effect in regulating the different signal molecules. Additional study suggested that JA upregulated the expression of Lexyl2, MAPK, and WRKY but downregulated atpA. Furthermore, JA also enhanced the activity of PAL, PPO, and CAT and the production of NO and H2O2. SA downregulated CAT and PAL, whereas ET upregulated PAL but downregulated CAT. This study is of significance in understanding the regulatory pathways and biocontrol mechanism of C. rosea against B. cinerea.


Assuntos
Ciclopentanos/farmacologia , Peróxido de Hidrogênio/química , Lycopersicon esculentum , Oxilipinas/farmacologia , Ácido Salicílico/farmacologia , Botrytis , Ciclopentanos/química , Etilenos/química , Oxilipinas/química , Doenças das Plantas , Transdução de Sinais
14.
Arch Microbiol ; 201(6): 769-785, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30843087

RESUMO

The present study was aimed to investigate the effects of plant growth promoting rhizobacteria (PGPR) and plant growth regulators (PGRs) on the physiology and yield of wheat grown in less fertile sandy soil. The isolated PGPR strains were identified by 16S-rRNA gene sequencing as Planomicrobium chinense (P1), Bacillus cereus (P2) and Pseudomonas fluorescens (P3). Wheat varieties (Galaxy-13 and Pak-2013) differing in sensitivity to drought were soaked in fresh cultures of bacterial isolates and the PGRs (salicylic acid and putrescine) were sprayed at 150 mg/L on seedlings at three leaf stage. PGPR and PGRs treated plants showed significant increase in the contents of chlorophyll, sugar and protein even under harsh environmental conditions. Drought stress enhanced the production of proline, antioxidant enzymes and lipid peroxidation but a decrease was noted in the biochemical content (i.e. chlorophyll, protein and sugar) of inoculated plants. PGPR inoculation also significantly enhanced the yield parameters (i.e. plant height, spike length, grain yield and weight) and improved the fertility status of sandy soil. The accumulation of macronutrient, total NO3-N and P concentration and soil moisture content of rhizosphere soil was also enhanced by PGPRs inoculation. It is concluded that the combined effects of PGPR and PGRs have profound effects on the biochemical responses and drought tolerance of wheat grown in sandy soils.


Assuntos
Bacillus cereus/isolamento & purificação , Planococáceas/fisiologia , Reguladores de Crescimento de Planta/farmacologia , Pseudomonas fluorescens/fisiologia , Triticum/microbiologia , Bacillus cereus/genética , Clorofila/metabolismo , Secas , Planococáceas/genética , Planococáceas/isolamento & purificação , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Pseudomonas fluorescens/genética , Pseudomonas fluorescens/isolamento & purificação , Putrescina/farmacologia , Ácido Salicílico/farmacologia , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Plântula/microbiologia , Solo/química , Microbiologia do Solo , Triticum/efeitos dos fármacos , Triticum/crescimento & desenvolvimento , Triticum/metabolismo
15.
Appl Microbiol Biotechnol ; 103(8): 3521-3535, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30852658

RESUMO

At present, anti-virulence drugs are being considered as potential therapeutic alternatives and/or adjuvants to currently failing antibiotics. These drugs do not kill bacteria but inhibit virulence factors essential for establishing infection and pathogenesis through targeting non-essential metabolic pathways reducing the selective pressure to develop resistance. We investigated the effect of naturally isolated plant compounds on the repression of the quorum sensing (QS) system which is linked to virulence/pathogenicity in Pseudomonas aeruginosa. Our results show that trans-cinnamaldehyde (CA) and salicylic acid (SA) significantly inhibit expression of QS regulatory and virulence genes in P. aeruginosa PAO1 at sub-inhibitory levels without any bactericidal effect. CA effectively downregulated both the las and rhl QS systems with lasI and lasR levels inhibited by 13- and 7-fold respectively compared to 3- and 2-fold reductions with SA treatment, during the stationary growth phase. The QS inhibitors (QSI) also reduced the production of extracellular virulence factors with CA reducing protease, elastase and pyocyanin by 65%, 22% and 32%, respectively. The QSIs significantly reduced biofilm formation and concomitantly with repressed rhamnolipid gene expression, only trace amount of extracellular rhamnolipids were detected. The QSIs did not completely inhibit virulence factor expression and production but their administration significantly lowered the virulence phenotypes at both the transcriptional and extracellular levels. This study shows the significant inhibitory effect of natural plant-derived compounds on the repression of QS systems in P. aeruginosa.


Assuntos
Acroleína/análogos & derivados , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/genética , Percepção de Quorum/efeitos dos fármacos , Ácido Salicílico/farmacologia , Fatores de Virulência/genética , Acroleína/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Espaço Extracelular/metabolismo , Pseudomonas aeruginosa/crescimento & desenvolvimento , Pseudomonas aeruginosa/patogenicidade , Percepção de Quorum/genética , Virulência/efeitos dos fármacos , Fatores de Virulência/metabolismo
16.
Ecotoxicol Environ Saf ; 172: 317-325, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30721875

RESUMO

Heavy metal toxicity is one of the main factors that limit crop growth and yield in the world. Salicylic acid (SA) is thought to be a plant hormone that plays an important role in plant growth, development, and resistance to abiotic stresses. To uncover the toxic alleviation effects of SA on potato plants to cadmium (Cd) stress, the morphological, physiological, and biochemical indexes including antioxidant defense system were assayed in potato plants under 200 µM Cd stress in 1/2 Hoagland solution with foliar application of 600 µM SA concentration (10 ml/plant). Interestingly, exogenous SA treatment mitigated Cd toxicity by increasing the relative water content (RWC), chlorophyll, proline, and endogenous SA contents along with decline in malondialdehyde (MDA), hydrogen peroxide (H2O2), and superoxide anion radicals (O2-). Correspondingly, our study also proved that SA may stimulate the antioxidant enzymatic mechanism pathway including superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6), ascorbate peroxidase (APX, EC 1.11.1.11), and glutathione reductase (GR, EC 1.6.4.2) in potato plants subjected to Cd stress. Moreover, the expression level of selected genes relate to SA and reactive oxygen species (ROS) metabolism (StSABP2, StSOD and StAPX) were enhanced in SA-treated potato plants under Cd stress, indicating that SA treatment regulated the expression of these genes, which in turn enhanced potato tolerance to Cd stress. Taken together, our results indicated that exogenous SA can play a positive regulatory role in alleviating Cd toxicity in potato plants.


Assuntos
Cádmio/toxicidade , Espécies Reativas de Oxigênio/metabolismo , Ácido Salicílico/farmacologia , Solanum tuberosum/efeitos dos fármacos , Ascorbato Peroxidases/metabolismo , Catalase/metabolismo , Clorofila/metabolismo , Estudos de Avaliação como Assunto , Regulação da Expressão Gênica de Plantas , Glutationa Redutase/metabolismo , Peróxido de Hidrogênio/metabolismo , Malondialdeído/metabolismo , Solanum tuberosum/metabolismo , Estresse Fisiológico/efeitos dos fármacos , Superóxido Dismutase/metabolismo , Superóxidos/metabolismo
17.
Food Chem ; 285: 380-388, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-30797360

RESUMO

This study investigated effects of the simultaneous application of thymol and salicylic acid (SIMTSA) on the target sites of Rhizopus stolonifer, as well as the defenceenzymes of postharvest tomato, when applied as edible coating. SIMTSA induced the changes of ultrastructure and membrane integrity of R. stolonifer. When the concentrations of the fungistat increased, cells stained with propidium iodide and leakage of 260/280 nm-absorbing materials increased while ergosterol synthesis decreased, suggesting damage of cell membrane. Furthermore, SIMTSA treatment significantly reduced the citric acid content and the activities of enzymes related to the tricarboxylic acid cycle, and increased the mitochondrial membrane potential and the reactive oxygen species, indicating damage of mitochondrial-related functions. Moreover, SIMTSA edible coating increased the defence enzyme activities in tomato. Based on the results, SIMTSA can be used as a potential preservation method for tomato as it showed a targeted effect on the cell membrane and mitochondria of R. stolonifer.


Assuntos
Antifúngicos/farmacologia , Lycopersicon esculentum/microbiologia , Rhizopus/efeitos dos fármacos , Ácido Salicílico/farmacologia , Timol/farmacologia , Membrana Celular/efeitos dos fármacos , Ácido Cítrico/metabolismo , Enzimas/metabolismo , Ergosterol/metabolismo , Microbiologia de Alimentos , Conservação de Alimentos/métodos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Rhizopus/citologia , Rhizopus/ultraestrutura
18.
BMC Plant Biol ; 19(1): 75, 2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30770731

RESUMO

BACKGROUND: Lipoxygenases (LOXs) play significant roles in abiotic stress responses, and identification of LOX gene promoter function can make an important contribution to elucidating resistance mechanisms. Here, we cloned the CmLOX08 promoter of melon (Cucumis melo) and identified the main promoter regions regulating transcription in response to signalling molecules and abiotic stresses. RESULTS: The 2054-bp promoter region of CmLOX08 from melon leaves was cloned, and bioinformatic analysis revealed that it harbours numerous cis-regulatory elements associated with signalling molecules and abiotic stress. Five 5'-deletion fragments obtained from the CmLOX08 promoter-2054 (LP1), 1639 (LP2), 1284 (LP3), 1047 (LP4), and 418 bp (LP5)-were fused with a GUS reporter gene and used for tobacco transient assays. Deletion analysis revealed that in response to abscisic acid, salicylic acid, and hydrogen peroxide, the GUS activity of LP1 was significantly higher than that of the mock-treated control and LP2, indicating that the - 2054- to - 1639-bp region positively regulates expression induced by these signalling molecules. However, no deletion fragment GUS activity was induced by methyl jasmonate. In response to salt, drought, and wounding treatments, LP1, LP2, and LP4 promoted significantly higher GUS expression compared with the control. Among all deletion fragments, LP4 showed the highest GUS expression, indicating that - 1047 to - 1 bp is the major region regulating promoter activity and that the - 1047 to - 418-bp region positively regulates expression induced by salt, drought, and wounding, whereas the - 1284 to - 1047-bp region is a negative regulatory segment. Interestingly, although the GUS activity of LP1 and LP2 was not affected by temperature changes, that of LP3 was significantly induced by heat, indicating that the - 1284- to - 1-bp region is a core sequence responding to heat and the - 2054- to - 1284-bp region negatively regulates expression induced by heat. Similarly, the - 1047- to - 1-bp region is the main sequence responding to cold, whereas the - 2054- to - 1047-bp region negatively regulates expression induced by cold. CONCLUSIONS: We cloned the CmLOX08 promoter and demonstrated that it is a signalling molecule/stress-inducible promoter. Furthermore, we identified core and positive/negative regulatory regions responding to three signalling molecules and five abiotic stresses.


Assuntos
Cucumis melo/genética , Regulação da Expressão Gênica de Plantas , Reguladores de Crescimento de Planta/farmacologia , Regiões Promotoras Genéticas/genética , Transdução de Sinais , Estresse Fisiológico , Ácido Abscísico/farmacologia , Acetatos/farmacologia , Cucumis melo/fisiologia , Ciclopentanos/farmacologia , Secas , Genes Reporter , Peróxido de Hidrogênio/farmacologia , Oxilipinas/farmacologia , Ácido Salicílico/farmacologia , Cloreto de Sódio/farmacologia
19.
J Agric Food Chem ; 67(7): 1807-1813, 2019 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-30734556

RESUMO

The chemotactic activity of the pathogen of bacterial wilt disease, Ralstonia solanacearum, was tested against 30 aromatic acids and plant hormones infused on filter discs in bioassays on agar plates. 4-Hydroxycinnamic acid ( p-coumaric acid) and 4-hydroxybenzoic acid were strong chemoattractants, 3,4-dihydroxybenzoic acid (protocatechuic acid) and jasmonic acid were weak attractants, and 2-hydroxybenzoic acid (salicylic acid) showed both attracting and repelling activity depending on dose. Examination of the dose dependency revealed that the ED50 for 4-hydroxycinnamic acid and 4-hydroxybenzoic acid was 0.08 and 0.39 µmol/disc, respectively. 2-Hydroxybenzoic acid showed chemoattractant activity at 0.33 µmol/disc but chemorepellent activity at 3.3 µmol/disc, and bacterial random motility was activated at 1.0 µmol/disc and bacterial activity was suppressed at 33 µmol/disc. Although water-soluble attractants including amino acids and organic acids have been previously investigated, this is the first report of hydroxylated aromatic acids (HAAs) as chemoattractants of R. solanacearum.


Assuntos
Fatores Quimiotáticos/farmacologia , Quimiotaxia/efeitos dos fármacos , Lycopersicon esculentum/metabolismo , Ralstonia solanacearum/efeitos dos fármacos , Ralstonia solanacearum/fisiologia , Fatores Quimiotáticos/isolamento & purificação , Ácidos Cumáricos/farmacologia , Relação Dose-Resposta a Droga , Flavonoides/farmacologia , Parabenos/farmacologia , Doenças das Plantas/microbiologia , Reguladores de Crescimento de Planta/farmacologia , Raízes de Plantas/química , Propionatos/farmacologia , Ácido Salicílico/farmacologia
20.
Biomolecules ; 9(1)2019 01 12.
Artigo em Inglês | MEDLINE | ID: mdl-30642071

RESUMO

Plants absorb melatonin from the environments as well as they synthesize the regulatory molecule. We applied melatonin to the roots of maize (Zea mays) seedlings and examined its accumulation in the leaves. Melatonin accumulation in the leaves was proportional to the exogenously applied concentrations up to 5 mM, without saturation. Time-course analysis of the accumulated melatonin content did not show an adaptable (or desensitizable) uptake system over a 24-h period. Melatonin accumulation in the leaves was reduced significantly by the plant hormones abscisic acid (ABA) and salicylic acid (SA), which commonly cause stomatal closure. The application of ABA and benzo-18-crown-6 (18-CR, a stomata-closing agent) induced stomatal closure and simultaneously decreased melatonin content in the leaves. When plants were shielded from airflow in the growth chamber, melatonin accumulation in the leaves decreased, indicating the influence of reduced transpiration. We conclude that melatonin applied exogenously to the root system is absorbed, mobilized upward according to the transpirational flow, and finally accumulated in the leaves.


Assuntos
Melatonina/farmacologia , Plântula/efeitos dos fármacos , Ácido Abscísico/farmacologia , Cromatografia Líquida de Alta Pressão , Éteres de Coroa/farmacologia , Melatonina/análise , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Estômatos de Plantas/efeitos dos fármacos , Estômatos de Plantas/metabolismo , Ácido Salicílico/farmacologia , Zea mays/efeitos dos fármacos , Zea mays/crescimento & desenvolvimento , Zea mays/metabolismo
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