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1.
World J Microbiol Biotechnol ; 35(7): 106, 2019 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-31267229

RESUMO

Xenorhabdus nematophila HB310 secreted the insecticidal protein toxin complex. Two chitinase genes, chi60 and chi70, were found in X. nematophila toxin complex locus. In order to clarify the function of two chitinases, chi60 and chi70 genes were cloned and expressed in Escherichia coli Transetta (DE3). As a result, we found that the Chi60 and Chi70 belonged to glycoside hydrolases (GH) family 18 with a molecular mass of 65 kDa and 78 kDa, respectively. When colloidal chitin was treated as the substrate, Chi60 and Chi70 were proved to have the highest enzymatic activity at pH 6.0 and 50 °C. Chi60 and Chi70 had obvious growth inhibition effect against the second larvae of Helicoverpa armigera with growth inhibiting rate of 81.99% and 90.51%. Chi70 had synergistic effect with the insecticidal toxicity of Bt Cry 1Ac, but the Chi60 had no synergistic effect with Bt Cry 1Ac. Chi60 and Chi70 showed antifungal activity against Alternaria brassicicola, Verticillium dahliae and Coniothyrium diplodiella. The results increased our understanding of the chitinases produced by X. nematophila and laid a foundation for further studies on the mechanism of the chitinases.


Assuntos
Antifúngicos/farmacologia , Quitinases/antagonistas & inibidores , Quitinases/genética , Quitinases/metabolismo , Xenorhabdus/metabolismo , Alternaria/efeitos dos fármacos , Animais , Ascomicetos/efeitos dos fármacos , Quitina/metabolismo , Quitinases/classificação , Clonagem Molecular , Sinergismo Farmacológico , Ensaios Enzimáticos , Estabilidade Enzimática , Escherichia coli/genética , Expressão Gênica , Glicosídeo Hidrolases/genética , Concentração de Íons de Hidrogênio , Inseticidas/metabolismo , Inseticidas/farmacologia , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Peso Molecular , Mariposas/efeitos dos fármacos , Mariposas/crescimento & desenvolvimento , Micotoxinas/genética , Micotoxinas/metabolismo , Filogenia , Domínios Proteicos , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Temperatura Ambiente , Verticillium/efeitos dos fármacos , Xenorhabdus/genética
2.
Int J Mol Sci ; 19(12)2018 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-30545043

RESUMO

The homeodomain-leucine zipper (HD-ZIP) is a plant-specific transcription factor family that plays important roles in plant developmental processes in response to multiple stressors. We previously isolated a cotton HD-ZIP class I transcription factor gene, GhHB12, which is regulated by the circadian clock and photoperiodism. Furthermore, it regulates cotton architecture, phase transition, and photoperiod sensitivity. Here we report that GhHB12 was induced by methyl jasmonate (MeJA) and Verticillium dahliae infection. Additionally, stress-responsive elements were found in the GhHB12 promoter. Promoter fusion analysis showed that GhHB12 was predominantly expressed in primary roots and that it was induced by mechanical damage. Overexpression of GhHB12 increased susceptibility of the cotton plant to the fungal pathogens Botrytis cinerea and V. dahliae, which was coupled with suppression of the jasmonic acid (JA)-response genes GhJAZ2 and GhPR3. Our results suggest that GhHB12, a cotton stress-responsive HD-ZIP I transcription factor, negatively regulates cotton resistance to V. dahliae by suppressing JA-response genes.


Assuntos
Resistência à Doença , Gossypium/imunologia , Gossypium/microbiologia , Proteínas de Homeodomínio/metabolismo , Doenças das Plantas/microbiologia , Fatores de Transcrição/metabolismo , Verticillium/fisiologia , Acetatos/farmacologia , Botrytis/efeitos dos fármacos , Botrytis/fisiologia , Ciclopentanos/farmacologia , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Genes de Plantas , Glucuronidase/metabolismo , Gossypium/genética , Proteínas de Homeodomínio/genética , Oxilipinas/farmacologia , Doenças das Plantas/genética , Plantas Geneticamente Modificadas , Fatores de Transcrição/genética , Verticillium/efeitos dos fármacos
3.
J Chem Ecol ; 44(4): 374-383, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29492723

RESUMO

Bacillus subtilis has shown success in antagonizing plant pathogens where strains of the bacterium produce antimicrobial cyclic lipopeptides (CLPs) in response to microbial competitors in their ecological niche. To gain insight into the inhibitory role of these CLPs, B. subtilis strain B9-5 was co-cultured with three pathogenic fungi. Inhibition of mycelial growth and spore germination was assessed and CLPs produced by B. subtilis B9-5 were quantified over the entire period of microbial interaction. B. subtilis B9-5 significantly inhibited mycelial growth and spore germination of Fusarium sambucinum and Verticillium dahliae, but not Rhizopus stolonifer. LC-MS analysis revealed that B. subtilis differentially produced fengycin and surfactin homologs depending on the competitor. CLP quantification suggested that the presence of Verticillium dahliae, a fungus highly sensitive to the compounds, caused an increase followed by a decrease in CLP production by the bacterium. In co-cultures with Fusarium sambucinum, a moderately sensitive fungus, CLP production increased more gradually, possibly because of its slower rate of spore germination. With co-cultures of the tolerant fungus Rhizopus stolonifer, B. subtilis produced high amounts of CLPs (per bacterial cell) for the duration of the interaction. Variations in CLP production could be explained, in part, by the pathogens' overall sensitivities to the bacterial lipopeptides and/or the relative growth rates between the plant pathogen and B. subtilis. CLP production varied substantially temporally depending on the targeted fungus, which provides valuable insight concerning the effectiveness of B. subtilis B9-5 protecting its ecological niche against the ingress of these pathogens.


Assuntos
Peptídeos Catiônicos Antimicrobianos/química , Bacillus subtilis/metabolismo , Fusarium/fisiologia , Lipopeptídeos/química , Peptídeos Catiônicos Antimicrobianos/isolamento & purificação , Peptídeos Catiônicos Antimicrobianos/farmacologia , Cromatografia Líquida de Alta Pressão , Fusarium/efeitos dos fármacos , Fusarium/isolamento & purificação , Lipopeptídeos/isolamento & purificação , Lipopeptídeos/farmacologia , Espectrometria de Massas , Peptídeos Cíclicos/química , Peptídeos Cíclicos/isolamento & purificação , Peptídeos Cíclicos/farmacologia , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Rhizopus/efeitos dos fármacos , Rhizopus/isolamento & purificação , Rhizopus/fisiologia , Esporos Fúngicos/efeitos dos fármacos , Esporos Fúngicos/crescimento & desenvolvimento , Verticillium/efeitos dos fármacos , Verticillium/isolamento & purificação , Verticillium/fisiologia
4.
Plant Cell Physiol ; 59(2): 275-289, 2018 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-29165718

RESUMO

Verticillium wilt disease is one of the most destructive biotic stresses faced by cotton plants. Here, we performed a genome-wide association study (GWAS) in 215 Chinese Gossypium arboreum accessions inoculated as seedlings with Verticillium dahliae to identify candidate loci involved in wilt resistance. We identified 309 loci that had a significant association with Verticillium wilt resistance and - log(P) values >5.0; the highest signal appeared on Ca3 in a 74 kb haplotype block. Five genes were also located within this haplotype block. One of these genes, CG05, was positioned close to the most significant SNP Ca3_23037225 (14 kb); expression of the gene was induced by V. dahliae or by treatment with salicylic acid (SA). Therefore, we suggest that CG05 may respond to invasion by V. dahliae via an SA-related signaling pathway, and we designated this gene as GaGSTF9. We showed that GaGSTF9 was a positive regulator of Verticillium wilt through the use of virus-induced gene silencing (VIGS) and overexpression in Arabidopsis. In addition, the glutathione S-transferase (GST) mutant gstf9 of Arabidopsis was found to be more susceptible to Verticillium wilt than wild-type plants. The levels of endogenous SA and hydrogen peroxide had a significant effect on Arabidopsis plants that overexpressed GaGSTF9, indicating that GST may regulate reactive oxygen species content via catalytic reduction of the tripeptide glutathione (GSH), and then affect SA content. Our data demonstrated that GaGSTF9 was a key regulator mediating cotton responses to V. dahliae and a potential candidate gene for cotton genetic improvement.


Assuntos
Resistência à Doença/genética , Estudo de Associação Genômica Ampla , Glutationa Transferase/genética , Gossypium/enzimologia , Gossypium/microbiologia , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Verticillium/fisiologia , Arabidopsis/genética , Arabidopsis/microbiologia , Resistência à Doença/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Glutationa Transferase/metabolismo , Gossypium/efeitos dos fármacos , Gossypium/genética , Peróxido de Hidrogênio/metabolismo , Mutação/genética , Fenótipo , Reguladores de Crescimento de Planta/farmacologia , Plantas Geneticamente Modificadas , Polimorfismo de Nucleotídeo Único/genética , Ácido Salicílico/metabolismo , Sementes/efeitos dos fármacos , Sementes/microbiologia , Transdução de Sinais/efeitos dos fármacos , Verticillium/efeitos dos fármacos
5.
Pestic Biochem Physiol ; 143: 26-32, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29183602

RESUMO

The metallic complexes µ-chloro-µ-[2,5-bis (2-pyridyl)-1,3,4-thiadiazole] aqua chlorocopper (II) dichlorocopper (II) (abbreviated 2PTH-Cu2-Cl4); aquabis [2,5-bis (2-pyridyl)-1,3,4-thiadiazole-κ2N2,N3] (trifluoromethane-sulfonato-κO) copper(II) trifluoro metrhanesulfonate (2PTH-Cu-tF) and bis[(2,5-bis(pyridine-2-yl)-1,3,4-thiadiazole-di-azido copper(II)] (2PTH-Cu-Az) were compared for their antimicrobial activities in vitro, and their aptitude to control Verticillium wilt and crown gall diseases development of tomato in the greenhouse. Results showed that the complex 2PTH-Cu-Az inhibited drastically the growth of V. dahliae in vitro. 2PTH-Cu2-Cl4 and 2PTH-Cu-tF did not display any noticeable antimicrobial activity in vitro against all of the pathogens tested. However, in planta evaluation revealed that the three complexes protected tomato against crown gall similarly. They also reduced Verticillium wilt disease severity, although the complex 2PTH-Cu-Az was the most efficient. When compared to other complexes, 2PTH-Cu-Az triggered only a weak oxidative burst as revealed by H2O2 measurement and the activity of ascorbate peroxidase and catalase. These results suggest that the superiority of 2PTH-Cu-Az against V. dahliae rely on its direct antifungal activity and its ability to modulate H2O2 accumulation.


Assuntos
Antifúngicos/toxicidade , Cobre/toxicidade , Lycopersicon esculentum/microbiologia , Doenças das Plantas/prevenção & controle , Pseudomonas syringae/efeitos dos fármacos , Tiadiazóis/toxicidade , Verticillium/efeitos dos fármacos , Agrobacterium tumefaciens/efeitos dos fármacos , Agrobacterium tumefaciens/crescimento & desenvolvimento , Ascorbato Peroxidases/metabolismo , Catalase/metabolismo , Erwinia amylovora/efeitos dos fármacos , Erwinia amylovora/crescimento & desenvolvimento , Peróxido de Hidrogênio/metabolismo , Lycopersicon esculentum/metabolismo , Pseudomonas syringae/crescimento & desenvolvimento , Verticillium/crescimento & desenvolvimento
6.
Fungal Genet Biol ; 108: 26-35, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28917999

RESUMO

The fungus Verticillium dahliae causes vascular wilt disease on various plant species resulting in devastating yield losses worldwide. The capacity of V. dahliae to colonize in host plant xylem and disseminate by microsclerotia has led to studies to evaluate genes associated with pathogenesis and microsclerotia formation. Here, we identified and characterized a V. dahliae homolog to Skn7, a two-component stress response regulator of Saccharomyces cerevisiae. Results showed that melanized microsclerotia formation and conidiation were significantly inhibited in the VdSkn7 deletion mutants. VdSkn7-deficient mutants displayed severe growth defect under heat shock, cell wall perturbing agents and H2O2, and were significantly less virulent but were not sensitive to osmotic stresses compared to the wild-type strain. Finally, we demonstrated that VdSkn7 is required for the plant penetration. Taken together, our study thus provides new evidence on the functional conservation and divergence of Skn7 orthologs among fungal organisms and indicates that VdSkn7 contributes to microsclerotial development, virulence and stress response of V. dahliae.


Assuntos
Genes Fúngicos , Verticillium/genética , Proteínas Fúngicas/genética , Proteínas Fúngicas/fisiologia , Deleção de Genes , Resposta ao Choque Térmico , Peróxido de Hidrogênio/farmacologia , Mutagênese , Doenças das Plantas/microbiologia , Transdução de Sinais , Esporos Fúngicos , Tabaco/microbiologia , Verticillium/efeitos dos fármacos , Verticillium/patogenicidade , Verticillium/fisiologia , Virulência
7.
Carbohydr Polym ; 165: 334-343, 2017 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-28363557

RESUMO

Verticillium dahliae, which causes wilting in over 300 woody and herbaceous plant species, is a representative of fungal plant diseases for which effective controls are still needed. In this study, the antifungal action of oleoyl-chitosan nanoparticles was investigated against V. dahliae. Media containing oleoyl-chitosan nanoparticles dramatically decreased the mycelium growth. The highest antifungal indexes were observed on media amended with 2mg/mL nanoparticles. Optical microscopy showed that spore germination and hyphae morphology were affected. Scanning electron microscopy and transmission electron microscopy demonstrated degenerative alterations including crumpled hyphae and spores, thickened cell walls, disappeared membranous organelles, massive vacuolation of the cytoplasm, and cell wall-plasmalemma separation. Fluorescence microscopy showed that nanoparticles were internalized by fungal cells. The sharp increase in the release of intracellular components and decrease of total cellular protein concentration demonstrated damaged cell membranes. Overall, the results indicate that oleoyl-chitosan nanoparticles have the potential to control phytopathogens in agriculture.


Assuntos
Quitosana/química , Fungicidas Industriais/química , Nanopartículas , Verticillium/efeitos dos fármacos , Permeabilidade
8.
Microbiol Res ; 196: 80-88, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28164793

RESUMO

The production of biocontrol factors by Pseudomonads is reported to be controlled at the post-transcriptional level by the GacS/GacA signal transduction pathway. This involves RNA-binding translational repressor proteins, RsmA and RsmE, and the small regulatory RNAs (sRNAs) RsmX, RsmY, and RsmZ. While the former represses genes involved in secondary metabolite production, the latter relieves this repression at the end of exponential growth. We have studied the fluorescent Pseudomonas strain Psd, possessing good biocontrol potential, and confirmed the presence of rsmY and rsmZ by PCR amplification. Gene constructs for all the three small RNAs (RsmX, RsmY and RsmZ) carried on broad host-range plasmid, pME6032 were mobilized into strain Psd. Expression analysis of gacA in the recombinant strains over-expressing rsmX (Psd-pME7320), rsmY (Psd-pME6359) and rsmZ (Psd-pME6918) revealed a significant upregulation of the response regulator. Besides, a remarkable down-regulation of rsmA was also reported in all the strains. The variant strains were found to produce comparatively higher levels of phenazines. Indole acetic acid levels were higher to some extent, and strain Psd-pME6918 also showed elevated production of HCN. The tomato seedlings infected with Fusarium oxysporum and Verticillium dahliae in the presence of culture filtrate of the recombinant strains showed better plant protection response in comparison to the wild-type strain Psd. These results suggest that small RNAs are important determinants in regulation of the biocontrol property of strain Psd.


Assuntos
Controle Biológico de Vetores , Pseudomonas/genética , Pseudomonas/metabolismo , RNA Bacteriano/genética , Antifúngicos/isolamento & purificação , Antifúngicos/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Sequência de Bases , DNA Bacteriano/genética , DNA Bacteriano/isolamento & purificação , Escherichia coli/genética , Fusarium/efeitos dos fármacos , Fusarium/patogenicidade , Ácidos Indolacéticos/metabolismo , Lycopersicon esculentum/efeitos dos fármacos , Lycopersicon esculentum/microbiologia , Fenazinas/metabolismo , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , RNA Bacteriano/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Plântula/microbiologia , Análise de Sequência de DNA , Sideróforos/metabolismo , Transdução de Sinais , Fatores de Transcrição/genética , Transcrição Genética , Ativação Transcricional , Verticillium/efeitos dos fármacos , Verticillium/patogenicidade
9.
Nat Prod Res ; 31(10): 1142-1149, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-27653454

RESUMO

A series of 21 N-protected tryptophan derivatives were synthesised from tryptophan in good yields. Their structures were characterised by IR, 1H NMR, 13C NMR, DEPT (90° and 135°) and MS analysis. The synthesised compounds were evaluated against a wide variety of plant pathogen fungi. Compounds a19 and a21 displayed activity against Fusarium oxysporum (F. oxysporum), and compound a21 showed high activity against F. oxysporum and Eggplant Verticillium, with EC50 values of 58.27 and 77.39 µg mL-1, respectively. Considering that the bioassay of the title compounds was evaluated, effects of the chain alkyl substituents may contribute to the significant variations in fungicidal potency. Their structure-antifungal activity relationships were also discussed. These results will pave the way for further design, structural modification and development of calycanthaceous alkaloids as antimicrobial agents.


Assuntos
Alcaloides/química , Alcaloides/farmacologia , Antifúngicos/síntese química , Antifúngicos/farmacologia , Naftiridinas/química , Naftiridinas/farmacologia , Triptofano/análogos & derivados , Triptofano/farmacologia , Fungos/efeitos dos fármacos , Fusarium/efeitos dos fármacos , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Testes de Sensibilidade Microbiana , Micélio/efeitos dos fármacos , Micélio/crescimento & desenvolvimento , Doenças das Plantas/microbiologia , Esporos Fúngicos/efeitos dos fármacos , Relação Estrutura-Atividade , Triptofano/síntese química , Verticillium/efeitos dos fármacos
10.
Phytochemistry ; 135: 169-180, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28027775

RESUMO

Oxidation of α-euphorbol and 31-norlanostenol, two triterpenic compounds isolated from the latex of Euphorbia resinifera and Euphorbia officinarum respectively, yielded four products named 3ß-tosyloxy-4α,14α-dimethyl-5α-cholesta-7,9-diene; 4α,14α-dimethyl-5α-cholesta-7,9-dien-3ß-ol; 24-methylen-elemo-lanosta-8,24-dien-3-one and elemo-lanost-8-en-3,11,24-trione. They were evaluated for protection of tomato plants against Verticillium dahliae in a greenhouse. The four semisynthesized products were phytotoxic at higher concentrations as they completely inhibited tomato germination at 100 and 500 µg/ml. However at lower concentrations (10 and 50 µg/ml) germination and root length were not affected. Disease resistance against Verticillium wilt was assessed in tomato plants derived from seeds that germinated in the presence of 10 and 50 µg/ml of the four products. All of them were able to reduce significantly disease severity, with 10 µg/ml being more effective than 50 µg/ml. Reduction of leaf alteration index and of stunting index ranged from 52 to 68% and from 43 to 67%, respectively, while vessel discoloration was reduced by at least 95%. The compounds were also able to elicit H2O2 accumulation before and after fungal inoculation and to significantly enhance peroxidase and polyphenol oxidase activities. These results suggest that the hemisynthetized triterpenes can be used as elicitors of disease resistance.


Assuntos
Lycopersicon esculentum/efeitos dos fármacos , Triterpenos/isolamento & purificação , Triterpenos/farmacologia , Verticillium/efeitos dos fármacos , Farmacorresistência Fúngica/efeitos dos fármacos , Peróxido de Hidrogênio/análise , Lycopersicon esculentum/crescimento & desenvolvimento , Estrutura Molecular , Triterpenos/química
11.
Pest Manag Sci ; 73(1): 188-197, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27040738

RESUMO

BACKGROUND: The antifungal properties of the nickel(II) complex bis(azido-κN)bis[2,5-bis(pyridin-2-yl)-1,3,4-thiadiazole-κ2 N2 ,N3 ]nickel(II) [NiL2 (N3 )2 ] and its parental ligand 2,5-bis(pyridin-2-yl)-1,3,4-thiadiazole were examined to evaluate their ability to protect tomato plants against Verticillium dahliae. Our main objectives were to determine their effects on the in vitro growth of the pathogen, and their aptitude for controlling verticillium wilt and activating plant defence responses in the greenhouse. RESULTS: NiL2 (N3 )2 exhibited in vitro an elevated inhibition of radial growth of three strains of the pathogen. According to the strain, the EC50 values ranged from 10 to 29 µg mL-1 for NiL2 (N3 )2 . In the greenhouse, it induced an elevated protection against V. dahliae when it was applied twice as foliar sprays at 50 µg mL-1 . It reduced the leaf alteration index by 85% and vessel browning by 96%. In addition, its protective ability was associated with the accumulation of H2 O2 and the activation of total phenolic content, as well as potentiation of the activity of peroxidase and polyphenol oxidase. CONCLUSION: These results demonstrated that the coordination of the ligand with Ni associated with the azide as a coligand resulted in an improvement in its biological activity by both inhibiting the growth of V. dahliae and activating plant defence responses. © 2016 Society of Chemical Industry.


Assuntos
Antifúngicos/farmacologia , Lycopersicon esculentum/microbiologia , Níquel/farmacologia , Doenças das Plantas/prevenção & controle , Tiadiazóis/farmacologia , Verticillium/efeitos dos fármacos , Antifúngicos/química , Testes de Sensibilidade Microbiana , Doenças das Plantas/microbiologia , Verticillium/crescimento & desenvolvimento
12.
J Gen Appl Microbiol ; 62(5): 233-239, 2016 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-27666589

RESUMO

In this paper, rhamnolipids are investigated, for the first time, for their feasibility for inhibiting dimorphic fungi. Rhamnolipids were found to effectively inhibit a dimorphic fungus isolated from tomato plants which was identified as Mucor circinelloides according to characterizations by morphologies as well as 28S rDNA sequences. Rhamnolipids markedly reduced growth of this fungus in both the yeast-like form and the filamentous form. Such an inhibitive effect was similarly obtained with Verticillium dahliae, a representative member of dimorphic fungi, confirming the effectiveness of rhamnolipids in the two growth forms of dimorphic fungi. Interestingly, rhamnolipids showed a greater inhibitive function in the case of the pathogenic growth mode of dimorphic fungi, such as the mycelium growth for M. circinelloides and the yeast-like growth for V. dahliae, than their non-pathogenic modes. The use of rhamnolipids might greatly reduce the frequently-reported drugresistance to the common anti-fungal agents by deterring the possible switch between the two modes of dimorphic fungi. Overall, rhamnolipids as environment-friendly biocontrol agents have a potential use in protecting plants from dimorphic fungi infections, and could also offer guidance toward future research into controlling dimorphic disease infection in humans.


Assuntos
Antifúngicos/farmacologia , Glicolipídeos/farmacologia , Mucor/efeitos dos fármacos , Verticillium/efeitos dos fármacos , Antifúngicos/química , Agentes de Controle Biológico/farmacologia , Humanos , Lycopersicon esculentum/microbiologia , Mucor/genética , Mucor/crescimento & desenvolvimento , Mucor/isolamento & purificação , Micélio/efeitos dos fármacos
13.
Plant Cell Rep ; 35(10): 2167-79, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27432176

RESUMO

KEY MESSAGE: Dual function of GhATAF1 in the responses to salinity stress and Verticillium dahliae infection in cotton. NAC (NAM/ATAF1/2/CUC2) is a large plant-specific transcription factor family that plays important roles in the response to abiotic stresses. We previously isolated a cotton NAC transcription factor gene, GhATAF1, which was up-regulated by ABA, cold and salt stresses and classified into AFAT1/2, a sub-family of NAC. Here, we report that GhATAF1 was also highly induced by MeJA, SA and Verticillium dahliae inoculation, which implied that GhATAF1 was involved not only in the response to abiotic stress but also in the response to biotic stress. GhATAF1 was localized in the nucleus and possessed transactivation activity. Overexpression of GhATAF1 enhanced cotton plant tolerance to salt stress by enhancing the expression of various stress-related genes, including the ABA response gene GhABI4; the transporter gene GhHKT1, involved in Na(+)/K(+) homeostasis; and several stress-response genes (GhAVP1, GhRD22, GhDREB2A, GhLEA3, and GhLEA6). Additionally, overexpressing GhATAF1 increased cotton plant susceptibility to the fungal pathogens V. dahliae and Botrytis cinerea, coupled with the suppression of JA-mediated signaling and the activation of SA-mediated signaling. Our results suggested that GhATAF1, the cotton stress-responsive NAC transcription factor, plays important roles in the response to both abiotic stress and biotic stress by coordinating the phytohormone signaling networks.


Assuntos
Gossypium/microbiologia , Gossypium/fisiologia , Reguladores de Crescimento de Planta/metabolismo , Proteínas de Plantas/metabolismo , Transdução de Sinais , Estresse Fisiológico , Fatores de Transcrição/metabolismo , Sequência de Aminoácidos , Arabidopsis/genética , Ciclopentanos/farmacologia , Resistência à Doença , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Gossypium/metabolismo , Oxilipinas/farmacologia , Doenças das Plantas/microbiologia , Reguladores de Crescimento de Planta/farmacologia , Proteínas de Plantas/química , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Ácido Salicílico/farmacologia , Tolerância ao Sal/efeitos dos fármacos , Tolerância ao Sal/genética , Alinhamento de Sequência , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Estresse Fisiológico/efeitos dos fármacos , Estresse Fisiológico/genética , Frações Subcelulares/metabolismo , Fatores de Transcrição/química , Fatores de Transcrição/genética , Ativação Transcricional/efeitos dos fármacos , Ativação Transcricional/genética , Verticillium/efeitos dos fármacos
14.
J Biotechnol ; 230: 26-7, 2016 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-27184432

RESUMO

Bacillus subtilis BSD-2, isolated from cotton (Gossypium spp.), had strong antagonistic activity to Verticillium dahlia Kleb and Botrytis cinerea. We sequenced and annotated the BSD-2 complete genome to help us the better use of this strain, which has surfactin, bacilysin, bacillibactin, subtilosin A, Tas A and a potential class IV lanthipeptide biosynthetic pathways.


Assuntos
Antifúngicos/farmacologia , Bacillus subtilis/genética , Genoma Bacteriano/genética , Gossypium/microbiologia , Antifúngicos/química , Antifúngicos/metabolismo , Bacillus subtilis/química , Bacillus subtilis/metabolismo , Botrytis/efeitos dos fármacos , Verticillium/efeitos dos fármacos
15.
Mol Genet Genomics ; 291(4): 1647-61, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27138919

RESUMO

BTD-S is a synthetic non-cyclic θ-defensin derivative which was previously designed in our laboratory based on baboon θ-defensins (BTDs). It shows robust antimicrobial activity against economically important phytopathogen, Verticillium dahliae. Here, we deduced the coding nucleotide sequence of BTD-S and introduced the gene into wild-type (ecotype Columbia-0) Arabidopsis thaliana plants. Results demonstrated that BTD-S-transgenic lines displayed in bioassays inhibitory effects on the growth of V. dahliae in vivo and in vitro. Based on symptom severity, enhanced resistance was found in a survey of BTD-S-transgenic lines. Besides, crude protein extracts from root tissues of BTD-S-transformed plants significantly restricted the growth of fungal hyphae and the germination of conidia. Also, fungal biomass over time determined by real-time PCR demonstrated the overgrowth of V. dahliae in wild-type plants 2-3 weeks after inoculation, while almost no fungal DNA was detected in aerial tissues of their transgenic progenitors. The result suggested that fungus failed to invade and progress acropetally up to establish a systemic infection in BTD-S-transgenic plants. Moreover, the assessment of basal defense responses was performed in the leaves of WT and BTD-S-transgenic plants. The mitigated oxidative stress and low antioxidase level in BTD-S-transgenic plants revealed that BTD-S acts via permeabilizing target microbial membranes, which is in a category different from hypersensitive response-dependent defense. Taken together, our results demonstrate that BTD-S is a promising gene to be explored for transgenic engineering for plant protection against Verticillium wilt.


Assuntos
Peptídeos Catiônicos Antimicrobianos/genética , Arabidopsis/crescimento & desenvolvimento , Resistência à Doença , Proteínas de Plantas/genética , Peptídeos Catiônicos Antimicrobianos/farmacologia , Arabidopsis/genética , Arabidopsis/microbiologia , DNA Fúngico/análise , Genes Sintéticos , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/microbiologia , Proteínas de Plantas/metabolismo , Raízes de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Verticillium/efeitos dos fármacos , Verticillium/genética
16.
FEMS Microbiol Ecol ; 92(6): fiw070, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27053756

RESUMO

Biotic interactions through volatile organic compounds (VOC) are frequent in nature. This investigation aimed to study the role of ITALIC! BacillusVOC for the beneficial effects on plants observed as improved growth and pathogen control. Four ITALIC! Bacillus amyloliquefacienssubsp. ITALIC! plantarumstrains were screened for VOC effects on ITALIC! Arabidopsis thalianaCol-0 seedlings and ITALIC! Brassicafungal phytopathogens. VOC from all four ITALIC! Bacillusstrains could promote growth of ITALIC! Arabidopsisplants resulting in increased shoot biomass but the effects were dependent on the growth medium. Dose response studies with UCMB5113 on MS agar with or without root exudates showed significant plant growth promotion even at low levels of bacteria. ITALIC! BacillusVOC antagonized growth of several fungal pathogens ITALIC! in vitro However, the plant growth promotion efficacy and fungal inhibition potency varied among the ITALIC! Bacillusstrains. VOC inhibition of several phytopathogens indicated efficient microbial antagonism supporting high rhizosphere competence of the ITALIC! Bacillusstrains. GC-MS analysis identified several VOC structures where the profiles differed depending on the growth medium. The ability of ITALIC! Bacillusstrains to produce both volatile and soluble compounds for plant growth promotion and disease biocontrol provides examples of rhizosphere microbes as an important ecosystem service with high potential to support sustainable crop production.


Assuntos
Bacillus amyloliquefaciens/metabolismo , Agentes de Controle Biológico/farmacologia , Brassica/microbiologia , Desenvolvimento Vegetal/efeitos dos fármacos , Compostos Orgânicos Voláteis/farmacologia , Alternaria/efeitos dos fármacos , Arabidopsis/microbiologia , Ascomicetos/efeitos dos fármacos , Biomassa , Botrytis/efeitos dos fármacos , Ecossistema , Doenças das Plantas/microbiologia , Raízes de Plantas/microbiologia , Rizosfera , Plântula/microbiologia , Verticillium/efeitos dos fármacos
17.
J Integr Plant Biol ; 58(5): 503-13, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26407676

RESUMO

Development of pathogen-resistant crops, such as fungus-resistant cotton, has significantly reduced chemical application and improved crop yield and quality. However, the mechanism of resistance to cotton pathogens such as Verticillium dahliae is still poorly understood. In this study, we characterized a cotton gene (HDTF1) that was isolated following transcriptome profiling during the resistance response of cotton to V. dahliae. HDTF1 putatively encodes a homeodomain transcription factor, and its expression was found to be down-regulated in cotton upon inoculation with V. dahliae and Botrytis cinerea. To characterise the involvement of HDTF1 in the response to these pathogens, we used virus-induced gene silencing (VIGS) to generate HDTF1-silenced cotton. VIGS reduction in HDTF1 expression significantly enhanced cotton plant resistance to both pathogens. HDTF1 silencing resulted in activation of jasmonic acid (JA)-mediated signaling and JA accumulation. However, the silenced plants were not altered in the accumulation of salicylic acid (SA) or the expression of marker genes associated with SA signaling. These results suggest that HDTF1 is a negative regulator of the JA pathway, and resistance to V. dahliae and B. cinerea can be engineered by activation of JA signaling.


Assuntos
Botrytis/fisiologia , Resistência à Doença/genética , Gossypium/genética , Gossypium/microbiologia , Proteínas de Homeodomínio/genética , Proteínas de Plantas/genética , Supressão Genética , Verticillium/fisiologia , Sequência de Aminoácidos , Botrytis/efeitos dos fármacos , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Ciclopentanos/metabolismo , Resistência à Doença/efeitos dos fármacos , Regulação para Baixo/efeitos dos fármacos , Regulação para Baixo/genética , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Técnicas de Silenciamento de Genes , Inativação Gênica/efeitos dos fármacos , Genes de Plantas , Gossypium/efeitos dos fármacos , Proteínas de Homeodomínio/metabolismo , Oxilipinas/metabolismo , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Reguladores de Crescimento de Planta/farmacologia , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Vírus de Plantas/fisiologia , Ácido Salicílico/metabolismo , Alinhamento de Sequência , Análise de Sequência de DNA , Transdução de Sinais/efeitos dos fármacos , Frações Subcelulares/metabolismo , Supressão Genética/efeitos dos fármacos , Tabaco/citologia , Verticillium/efeitos dos fármacos
18.
PLoS One ; 10(12): e0145190, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26670613

RESUMO

In fungal cells, a phosphate (Pi) responsive signaling and metabolism (PHO) pathway regulates Pi-homeostasis. NUC-2/PHO81 and its homologs are one of the most important components in the regulation pathway. In soil-borne phytopathogenic fungus Verticillium dahliae, we identified a Neurospora crassa nuc-2 homolog gene VdNUC-2. VdNUC-2 is composed of 1,018 amino acids, and is highly conserved in tested filamentous fungi. Under conditions of Pi-starvation, compared with the wild-type strain and ectopic complementation strains, the VdNUC-2 knocked out mutants exhibited reduced radial growth, decreased production of conidia and microsclerotia, and were more sensitive to hydrogen peroxide stress. The virulence of VdNUC-2 defective mutants was significantly compromised, and that was unable to be restored by exogenous application of extra Pi. Additionally, the deletion mutants of VdNUC-1, a key transcription factor gene positively controlled by VdNUC-2 in the PHO pathway, showed the similar cultural phenotypes as VdNUC-2 mutants when both of them grew in Pi-limited conditions. However, the virulence of VdNUC-1 mutants was comparable to the wild-type strain. These evidences indicated that the virulence reduction in VdNUC-2 mutants is not due to the interruptions in the PHO pathway or the disturbance of Pi-homeostasis in V. dahliae cytoplasm. VdNUC-2 is not only a crucial gene in the PHO pathway in V. dahliae, but also is required for the full virulence during host-infection.


Assuntos
Proteínas Fúngicas/metabolismo , Fosfatos/farmacologia , Doenças das Plantas/microbiologia , Transdução de Sinais/efeitos dos fármacos , Verticillium/patogenicidade , Sequência de Aminoácidos , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Regulação Fúngica da Expressão Gênica/efeitos dos fármacos , Marcação de Genes , Genes Fúngicos , Teste de Complementação Genética , Gossypium/efeitos dos fármacos , Gossypium/microbiologia , Proteínas de Fluorescência Verde/metabolismo , Dados de Sequência Molecular , Mutação/genética , Filogenia , Transporte Proteico/efeitos dos fármacos , Plântula/efeitos dos fármacos , Plântula/microbiologia , Transdução de Sinais/genética , Esporos Fúngicos/efeitos dos fármacos , Esporos Fúngicos/crescimento & desenvolvimento , Verticillium/efeitos dos fármacos , Verticillium/genética , Verticillium/crescimento & desenvolvimento , Virulência/efeitos dos fármacos , Virulência/genética
19.
Plant Signal Behav ; 10(9): e992285, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25875793

RESUMO

Nitric oxide (NO) is a major plant signaling molecule that plays key roles during plant-pathogen interactions and plant development. Previous work showed the participation of NO in the development and lignin composition of sunflower roots. Thereby, we have hypothesized that NO applications could control the attack of the fungal pathogen Verticillium dahliae in sunflowers. Seedlings growing hydroponically were pretreated with NO donors and further inoculated with the fungus. Evaluation of disease symptoms showed that NO pretreatments could not reduce Verticillium wilt. Strikingly, NO donors appear to promote the fungal infection. These results indicate that NO applications were unable to protect sunflowers from Verticillium attack and highlight the role played by the fine tuning regulation of NO levels required to balance plant responses between development and defense.


Assuntos
Helianthus/crescimento & desenvolvimento , Helianthus/imunologia , Óxido Nítrico/farmacologia , Desenvolvimento Vegetal/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Plântula/imunologia , Helianthus/efeitos dos fármacos , Helianthus/microbiologia , Hidroponia , Doadores de Óxido Nítrico/farmacologia , Doenças das Plantas/microbiologia , Plântula/efeitos dos fármacos , Plântula/microbiologia , Verticillium/efeitos dos fármacos , Verticillium/fisiologia
20.
Microb Biotechnol ; 8(4): 644-58, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25851532

RESUMO

We selected Streptomyces lividans to elucidate firstly the biogenesis and antimicrobial activities of extracellular vesicles that a filamentous and highly differentiated Gram-positive bacterium produces. Vesicle types range in diameter from 110 to 230 nm and 20 to 60 nm, respectively; they assemble to clusters, and contain lipids and phospholipids allowing their in situ imaging by specific fluorescent dyes. The presence of the identified secondary metabolite undecylprodigiosin provokes red fluorescence of a portion of the heterogeneous vesicle populations facilitating in vivo monitoring. Protuberances containing vesicles generate at tips, and alongside of substrate hyphae, and enumerate during late vegetative growth to droplet-like exudates. Owing to in situ imaging in the presence and absence of a green fluorescent vancomycin derivative, we conclude that protuberances comprising vesicles arise at sites with enhanced levels of peptidoglycan subunits [pentapeptide of lipid II (C55)-linked disaccharides], and reduced levels of polymerized and cross-linked peptidoglycan within hyphae. These sites correlate with enhanced levels of anionic phospholipids and lipids. Vesicles provoke pronounced damages of Aspergillus proliferans, Verticillium dahliae and induced clumping and distortion of Escherichia coli. These harmful effects are likely attributable to the action of the identified vesicular compounds including different enzyme types, components of signal transduction cascades and undecylprodigiosin. Based on our pioneering findings, we highlight novel clues with environmental implications and application potential.


Assuntos
Anti-Infecciosos/metabolismo , Vesículas Extracelulares/química , Vesículas Extracelulares/metabolismo , Lipídeos/análise , Streptomyces lividans/fisiologia , Aspergillus/efeitos dos fármacos , Parede Celular/química , Escherichia coli/efeitos dos fármacos , Biogênese de Organelas , Peptidoglicano/análise , Fosfolipídeos/análise , Streptomyces lividans/metabolismo , Verticillium/efeitos dos fármacos
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