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1.
Food Chem ; 301: 125224, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31374530

RESUMO

This study was the first investigation into the main inducers of two lignifications by examining the changes of physicochemical properties and gene expression in king oyster mushrooms, under different conditions, during 21 days of storage. The results showed that the toughness, firmness and gumminess of the no-wounding treatment decreased to approximately 75-82.5% of the initial values, and the lignin content and expression of Pe4CL1 and Pe4CL3 decreased by 21-40% and 22-77%, respectively, in comparison to those of the other treatments in the first lignification. These findings indicated that wounding was the main factor inducing the first lignification. The second lignification of tested mushrooms was positively correlated with reactive oxygen species (ROS)-mediated senescence, accompanied by increased malondialdehyde (MDA) content, electrolyte leakage rate and mitochondrial dysfunction, which showed that ROS-mediated senescence played an essential role in the second lignification. This study is helpful for effective strategies to reduce lignification in stored mushrooms.


Assuntos
Pleurotus/crescimento & desenvolvimento , Pleurotus/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Lignina/metabolismo , Malondialdeído/metabolismo , Pleurotus/fisiologia
2.
mSphere ; 4(3)2019 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-31142621

RESUMO

Sporisorium scitamineum is the fungal pathogen causing severe sugarcane smut disease that leads to massive economic losses globally. S. scitamineum invades host cane by dikaryotic hyphae, formed after sexual mating of two haploid sporidia of opposite mating type. Therefore, mating/filamentation is critical for S. scitamineum pathogenicity, while its molecular mechanisms remain largely unknown. The AGC (cyclic AMP [cAMP]-dependent protein kinase 1 [protein kinase A {PKA}], cGMP-dependent protein kinase [PKG], and protein kinase C [PKC]) kinase family is a group of serine/threonine (Ser/Thr) protein kinases conserved among eukaryotic genomes, serving a variety of physiological functions, including cell growth, metabolism, differentiation, and cell death. In this study, we identified an AGC kinase, named SsAgc1 (for S. scitamineum Agc1), and characterized its function by reverse genetics. Our results showed that SsAgc1 is critical for S. scitamineum mating/filamentation and pathogenicity, and oxidative stress tolerance under some circumstances. Transcriptional profiling revealed that the SsAgc1 signaling pathway may control expression of the genes governing fungal mating/filamentation and tryptophan metabolism, especially for tryptophol production. We showed that tryptophan and tryptophol could at least partially restore ssagc1Δ mating/filamentation. Overall, our work revealed a signaling pathway mediated by AGC protein kinases to regulate fungal mating/filamentation, possibly through sensing and responding to tryptophol as signal molecules.IMPORTANCE The AGC signaling pathway represents a conserved distinct signaling pathway in regulation of fungal differentiation and virulence, while it has not been identified or characterized in the sugarcane smut fungus Sporisorium scitamineum In this study, we identified a PAS domain-containing AGC kinase, SsAgc1, in S. scitamineum Functional analysis revealed that SsAgc1 plays a regulatory role on the fungal dimorphic switch.

3.
Food Chem ; 286: 226-233, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-30827600

RESUMO

Gray mold caused by Botrytis cinerea is a major postharvest disease of table grapes that leads to enormous economic losses during storage and transportation. The objective of this study was to evaluate the effectiveness of fulvic acid on controlling gray mold of table grapes and explore its mechanism of action. The results showed that fulvic acid application significantly reduced downy blight severity in table grapes without exhibiting any antifungal activity in vitro. Fulvic acid induced phenylpropanoid metabolism, as evidenced by accumulation of phenolic compounds and flavonoids, higher activities of phenylalanine ammonia-lyase (PAL), cinnamate-4-hydroxylase (C4H) and 4-coumarate-CoA ligase (4CL), up-regulation of genes related to phenylpropanoid biosynthesis (PAL, C4H, 4CL, STS, ROMT and CHS). Our results suggested that fulvic acid induces resistance to B. cinerea mainly through the activation of phenylpropanoid pathway and can be used as a new activator of plant defense responses to control postharvest gray mold in table grapes.


Assuntos
Benzopiranos/farmacologia , Botrytis/patogenicidade , Frutas/microbiologia , Vitis/metabolismo , Vitis/microbiologia , Botrytis/efeitos dos fármacos , Coenzima A Ligases/metabolismo , Resistência à Doença , Flavonoides/metabolismo , Microbiologia de Alimentos , Frutas/efeitos dos fármacos , Fungicidas Industriais/farmacologia , Fenilalanina Amônia-Liase/metabolismo , Fenilpropionatos/metabolismo , Doenças das Plantas/microbiologia , Proteínas de Plantas/metabolismo , Transcinamato 4-Mono-Oxigenase/metabolismo , Vitis/efeitos dos fármacos
4.
Mol Microbiol ; 111(6): 1493-1509, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30825339

RESUMO

Bacterial pathogen Dickeya zeae strain EC1 produces antibiotics-like phytotoxins called zeamines, which are major virulence determinants encoded by the zms gene cluster. In this study, we identified a zeamine-deficient mutant with a Tn5 insertion in a gene designated as vfmI encoding a two-component system (TCS) sensor histidine kinase (HK), which is accompanied by vfmH encoding a response regulator (RR) at the same genetic locus. Domain analysis shows this TCS is analogous to the VfmIH of D. dadantii, with typical characteristics of sensor HK and RR, respectively, and sharing the same operon. Deletion of either vfmI or vfmH resulted in decreased production of zeamines and cell wall degrading enzymes (CWDEs), and alleviated virulence on rice seeds and potato tubers. In D. dadantii 3937, VfmH was shown to bind to the promoters of vfmA and vfmE, while in D. zeae EC1, VfmH could bind to the promoters of vfmA, vfmE and vfmF. RNA-seq analysis of strain EC1 and its vfmH mutant also showed that the TCS positively regulated a range of virulence genes, including zms, T1SS, T2SS, T3SS, T6SS, flagellar and CWDE genes.

5.
Environ Microbiol ; 21(3): 959-971, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30537399

RESUMO

The fungal pathogen Sporisorium scitamineum causes sugarcane smut disease. The formation and growth of dikaryotic hypha after sexual mating is critical for S. scitamineum pathogenicity, however regulation of S. scitimineum mating has not been studied in detail. We identified and characterized the core components of the conserved cAMP/PKA pathway in S. scitamineum by reverse genetics. Our results showed that cAMP/PKA signalling pathway is essential for proper mating and filamentation, and thus critical for S. scitamineum virulence. We further demonstrated that an elevated intracellular ROS (reactive oxygen species) level promotes S. scitamineum mating-filamentation, via transcriptional regulation of ROS catabolic enzymes, and is under regulation of the cAMP/PKA signalling pathway. Furthermore, we found that fungal cAMP/PKA signalling pathway is also involved in regulation of host ROS response. Overall, our work displayed a positive role of elevated intracellular ROS in fungal differentiation and virulence.

6.
Front Microbiol ; 9: 2555, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30416495

RESUMO

In the phytopathogenic fungus Sporisorium scitamineum, sexual mating between two compatible haploid cells and the subsequent formation of dikaryotic hyphae is essential for infection. This process was shown to be commonly regulated by a mitogen-activated protein kinase (MAPK) and a cAMP/PKA signaling pathway in the corn smut fungus Ustilago maydis but remains largely unknown in S. scitamineum. In this study, we identified a conserved putative MAP kinase Kpp2 in S. scitamineum and named it as SsKpp2. The sskpp2Δ mutant displayed significant reduction in mating/filamentation, which could be partially restored by addition of cAMP or tryptophol, a quorum-sensing molecule identified in budding yeast. Transcriptional profiling showed that genes governing S. scitamineum mating or tryptophol biosynthesis were significantly differentially regulated in the sskpp2Δ mutant compared to the WT, under mating condition. Our results demonstrate that the MAP kinase SsKpp2 is required for S. scitamineum mating/filamentation likely through regulating the conserved pheromone signal transduction pathway and tryptophol production.

7.
Molecules ; 23(6)2018 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-29914082

RESUMO

Botrytis cinerea is the pathogen of gray mold disease affecting a wide range of plant hosts, with consequential economic losses worldwide. The increased frequency of fungicide resistance of the pathogen challenges its disease management, and thus the development of alternative control strategies are urgently required. In this study, we showed excellent synergistic interactions between resveratrol and pyrimethanil. Significant synergistic values were recorded by the two-drug combination on the suppression of mycelial growth and conidia germination of B. cinerea. The combination of resveratrol and pyrimethanil caused malformation of mycelia. Moreover, the inoculation assay was conducted on table grape and consistent synergistic suppression of the two-drug combination was found in vivo. Our findings first revealed that the combination of resveratrol and pyrimethanil has synergistic effects against resistant B. cinerea and support the potential use of resveratrol as a promising adjuvant on the control of gray mold.


Assuntos
Botrytis/efeitos dos fármacos , Doenças das Plantas/prevenção & controle , Pirimidinas/farmacologia , Estilbenos/farmacologia , Vitis/microbiologia , Farmacorresistência Fúngica/efeitos dos fármacos , Sinergismo Farmacológico , Micélio/efeitos dos fármacos , Doenças das Plantas/microbiologia , Resveratrol , Esporos Fúngicos/efeitos dos fármacos
8.
Gene ; 662: 123-130, 2018 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-29627524

RESUMO

Amanita exitialis Zhu L. Yang & T. H. Li is the species responsible for the largest number of mushroom-associated human poisonings and fatalities in South China due to its lethal cyclic peptide toxins. Prolyl oligopeptidase B (POPB) is considered a key enzyme in the production of the highly toxic cyclic peptide α-amanitin. However, the POPB gene of A. exitialis has not been studied. In the present study we cloned and sequenced the full-length A. exitialis POPB (AePOPB) gene. The aim was to verify the gene structure and functions of AePOPB. The full-length sequence of AePOPB is 3144 bp, including 18 exons encoding 730 aa, and the advanced structure is very similar to that of the previously reported POPB in Galerina marginata (GmPOPB). The amino acid sequence of AePOPB is highly homologous with those from other amanitin-producing lethal mushrooms, implying that AePOPB may have a similar role in the biosynthesis of cyclic peptide toxins. Expression levels of AePOPB were detectable in all parts and developmental stages of the fruiting bodies, and AePOPB was expressed more strongly at early development stages (early and late elongation stages). At early and late elongation stages, the expression peaks occurred in the stipe, whereas at early and late mature stages, the expression peaks occurred in the pileus. The expression patterns of AePOPB in different stages and different parts of the fruiting bodies were highly consistent with those of Aeα-AMA, which is required for α-amanitin accumulation. These results indicate that AePOPB should be involved in the α-amanitin biosynthesis in A. exitialis.


Assuntos
Alfa-Amanitina/genética , Amanita/genética , Serina Endopeptidases/genética , Alfa-Amanitina/biossíntese , Alfa-Amanitina/metabolismo , Amanitinas/genética , Amanitinas/metabolismo , Sequência de Aminoácidos , Sequência de Bases/genética , Clonagem Molecular/métodos , Carpóforos/genética , Regulação Fúngica da Expressão Gênica/genética , Peptídeos Cíclicos/genética , Filogenia , Serina Endopeptidases/metabolismo , Toxinas Biológicas/metabolismo
9.
Front Microbiol ; 9: 426, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29568294

RESUMO

Mitogen-activated protein kinase (MAPK) pathways are ubiquitous and evolutionarily conserved signal transduction modules directing cellular respond to a diverse array of stimuli, in the eukaryotic organisms. In this study, PlMAPK10 was identified to encode a MAPK in Peronophythora litchii, the oomycete pathogen causing litchi downy blight disease. PlMAPK10, containing a specific and highly conserved dual phosphorylation lip sequence SEY (Serine-Glutamic-Tyrosine), represents a novel group of MAPKs as previously reported. Transcriptional profiling showed that PlMAPK10 expression was up-regulated in zoospore and cyst stages. To elucidate its function, the PlMAPK10 gene was silenced by stable transformation. PlMAPK10 silence did not impair oospore production, sporangium germination, zoospore encyst, or cyst germination but hindered hyphal growth, sporulation, pathogenicity, likely due to altering laccase activity. Over all, our results indicated that a MAPK encoded by PlMAPK10 gene in P. litchii is important for pathogenic development.

10.
Molecules ; 23(2)2018 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-29419754

RESUMO

Litchi (Litchi chinensis Sonn.) is a commercially important fruit but its production and quality are restricted by litchi downy blight, caused by the oomycete pathogen Peronophythora litchii Chen. Volatile substances produced by a biocontrol antinomycetes Streptomyces fimicarius BWL-H1 could inhibited P. litchii growth and development both in vitro and in detached litchi leaf and fruit infection assay. Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) analyses indicated that volatile organic compounds (VOCs) from BWL-H1 resulted in severe damage to the endomembrane system and cell wall of P. litchii cells in vitro and abnormal morphology of appressoria, as well as deformed new hyphae in infection process. VOCs could suppress mycelial growth, sporulation, while with no obvious effect on sporangia germination. Based on gas chromatography-mass spectrophotometric analyses, 32 VOCs were identified from S. fimicarius BWL-H1, the most abundant of which was phenylethyl alcohol. Eight VOCs, including phenylethyl alcohol, ethyl phenylacetate, methyl anthranilate, α-copaene, caryophyllene, humulene, methyl salicylate and 4-ethylphenol, that are commercially available, were purchased and their bioactivity was tested individually. Except for humulene, the other seven tested volatile compounds shown strong inhibitory activity against mycelial growth, sporulation, sporangia germination and germ-tube growth of P. litchii. Especially, 4-ethylphenol showed the highest inhibitory effect on sporulation at a very low concentration of 2 µL/L. Overall, our results provided a better understanding of the mode of action of volatiles from BWL-H1 on P. litchii, and showed that volatiles from BWL-H1 have the potential for control of postharvest litchi downy blight.


Assuntos
Antifúngicos/química , Antifúngicos/farmacologia , Litchi/microbiologia , Phytophthora/efeitos dos fármacos , Compostos Orgânicos Voláteis/química , Compostos Orgânicos Voláteis/farmacologia , Testes de Sensibilidade Microbiana , Phytophthora/ultraestrutura , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Esporos Fúngicos/efeitos dos fármacos , Esporos Fúngicos/ultraestrutura
11.
Can J Microbiol ; 64(1): 57-68, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29084390

RESUMO

A rolling-circle amplification (RCA) method with padlock probes targeted on EF-1α regions was developed for rapid detection of apple bull's-eye rot pathogens, including Neofabraea malicorticis, N. perennans, N. kienholzii, and N. vagabunda (synonym: N. alba). Four padlock probes (PLP-Nm, PLP-Np, PLP-Nk, and PLP-Nv) were designed and tested against 28 samples, including 22 BER pathogen cultures, 4 closely related species, and 2 unrelated species that may cause serious apple decays. The assay successfully identified all the bull's-eye rot pathogenic fungi at the level of species, while no cross-reaction was observed in all target species and no false-positive reaction was observed with all strains used for reference. This study showed that the use of padlock probes and the combination of probe signal amplification by RCA provided an effective and sensitive method for the rapid identification of Neofabraea spp. The method could therefore be a useful tool for monitoring bull's-eye rot pathogens in port quarantine and orchard epidemiological studies.


Assuntos
Ascomicetos/genética , Malus/microbiologia , Técnicas Microbiológicas/métodos , Técnicas de Amplificação de Ácido Nucleico , Fator 1 de Elongação de Peptídeos/genética , Ascomicetos/classificação , Especificidade da Espécie
12.
Plant Dis ; 102(1): 172-178, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30673470

RESUMO

Leaf spots and stem lesions causing widespread mortality of Caspian Sea karelinia (Karelinia caspia) were observed in desert regions of Xinjiang Uyghur Autonomous Region, China. Fifteen samples were collected from five widely distributed counties of Tarim and Junggar Basins in 2016. The pathogen was identified using morphological observations and phylogenetic analyses based on combined partial sequences from seven genes (Alt a 1, ATPase, calmodulin, glyceraldehyde 3-phosphate dehydrogenase, internal transcribed spacer, RNA polymerase II, and translation elongation factor 1), and placed as a new species: Alternaria kareliniae sp. nov. in section Dianthicola. The fungus has a small conidium (24.3 to) 29.1 to 64.8 (to 75.8) by (9.3 to) 12.4 to 16.5 (to 21.7) µm with a long beak (130 to) 183.9 to 350.4 (to 378.2) µm, as well as four to eight transverse septa, which differs significantly from other species of Alternaria section Dianthicola. On potato carrot agar, it grew significantly more slowly than others of this section. Pathogenicity tests showed that the fungus could infect leaves and stems of K. caspia and cause the same symptoms as those observed in the field. The fungus was reisolated from inoculated leaves and stems of the host. The disease in desert regions appears to be increasing, and it may have future negative implications for desert ecology in these areas. Future research should concentrate on elucidating the disease cycle and disease management alternatives.


Assuntos
Alternaria/classificação , Asteraceae/microbiologia , Doenças das Plantas/microbiologia , Alternaria/enzimologia , Alternaria/genética , China , Proteínas Fúngicas/análise , Filogenia , RNA Fúngico/análise , Análise de Sequência de DNA
13.
Fungal Genet Biol ; 98: 39-45, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27939344

RESUMO

Sexual and asexual reproduction are two key processes in the pathogenic cycle of many filamentous pathogens. However in Peronophythora litchii, the causal pathogen for the litchi downy blight disease, critical regulator(s) of sexual or asexual differentiation has not been elucidated. In this study, we cloned a gene named PlM90 from P. litchii, which encodes a putative Puf RNA-binding protein. We found that PlM90 was highly expressed during asexual development, and much higher than that during sexual development, while relatively lower during cyst germination and plant infection. By polyethylene glycol (PEG)-mediated protoplast transformation, we generated three PlM90-silenced transformants and found a severely impaired ability in sexual spore production and a delay in stages of zoospore release and encystment. However, the pathogenicity of P. litchii was not affected by PlM90-silencing. Therefore we conclude that PlM90 specifically regulates the sexual and asexual differentiation of P. litchii.


Assuntos
Proteínas Fúngicas/genética , Phytophthora/genética , Proteínas de Ligação a RNA/genética , Reprodução Assexuada/genética , Esporos Fúngicos/genética , Sequência de Aminoácidos/genética , Frutas/genética , Frutas/microbiologia , Regulação Fúngica da Expressão Gênica , Inativação Gênica , Litchi/microbiologia , Phytophthora/crescimento & desenvolvimento , Phytophthora/patogenicidade , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , RNA/genética , Proteínas de Ligação a RNA/antagonistas & inibidores , Proteínas de Ligação a RNA/biossíntese , Esporos Fúngicos/crescimento & desenvolvimento , Esporos Fúngicos/patogenicidade
14.
Mar Drugs ; 14(12)2016 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-27999388

RESUMO

Cytoglobosins H (1) and I (2), together with seven known cytochalasan alkaloids (3-9), were isolated from the deep-sea-derived fungus Chaetomium globosum. The structures of new compounds 1 and 2 were elucidated by extensive 1D and 2D NMR and mass spectroscopic data. All the compounds were evaluated for their antiproliferative activities against MDA-MB-231 human breast cancer cells, LNCaP human prostate cancer cells, and B16F10 mouse melanoma cells. Compound 6 showed significant antiproliferative activity against LNCaP and B16F10 cell lines with IC50 values of 0.62 and 2.78 µM, respectively. Further testing confirmed that compound 6 inhibited the growth of LNCaP cells by inducing apoptosis.


Assuntos
Antineoplásicos/química , Chaetomium/química , Alcaloides Indólicos/química , Animais , Antineoplásicos/isolamento & purificação , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Chaetomium/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Ensaios de Seleção de Medicamentos Antitumorais , Fermentação , Humanos , Alcaloides Indólicos/isolamento & purificação , Alcaloides Indólicos/farmacologia , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Camundongos , Extração em Fase Sólida
15.
Front Microbiol ; 7: 1719, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27833603

RESUMO

Ralstonia solanacearum species complex is a devastating group of phytopathogens with an unusually wide host range and broad geographical distribution. R. solanacearum isolates may differ considerably in various properties including host range and pathogenicity, but the underlying genetic bases remain vague. Here, we conducted the genome sequencing of strain EP1 isolated from Guangdong Province of China, which belongs to phylotype I and is highly virulent to a range of solanaceous crops. Its complete genome contains a 3.95-Mb chromosome and a 2.05-Mb mega-plasmid, which is considerably bigger than reported genomes of other R. solanacearum strains. Both the chromosome and the mega-plasmid have essential house-keeping genes and many virulence genes. Comparative analysis of strain EP1 with other 3 phylotype I and 3 phylotype II, III, IV strains unveiled substantial genome rearrangements, insertions and deletions. Genome sequences are relatively conserved among the 4 phylotype I strains, but more divergent among strains of different phylotypes. Moreover, the strains exhibited considerable variations in their key virulence genes, including those encoding secretion systems and type III effectors. Our results provide valuable information for further elucidation of the genetic basis of diversified virulences and host range of R. solanacearum species.

16.
Mol Plant Microbe Interact ; 29(7): 573-83, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27183038

RESUMO

On the basis of its downy mildew-like morphology, the litchi downy blight pathogen was previously named Peronophythora litchii. Recently, however, it was proposed to transfer this pathogen to Phytophthora clade 4. To better characterize this unusual oomycete species and important fruit pathogen, we obtained the genome sequence of Phytophthora litchii and compared it to those from other oomycete species. P. litchii has a small genome with tightly spaced genes. On the basis of a multilocus phylogenetic analysis, the placement of P. litchii in the genus Phytophthora is strongly supported. Effector proteins predicted included 245 RxLR, 30 necrosis-and-ethylene-inducing protein-like, and 14 crinkler proteins. The typical motifs, phylogenies, and activities of these effectors were typical for a Phytophthora species. However, like the genome features of the analyzed downy mildews, P. litchii exhibited a streamlined genome with a relatively small number of genes in both core and species-specific protein families. The low GC content and slight codon preferences of P. litchii sequences were similar to those of the analyzed downy mildews and a subset of Phytophthora species. Taken together, these observations suggest that P. litchii is a Phytophthora pathogen that is in the process of acquiring downy mildew-like genomic and morphological features. Thus P. litchii may provide a novel model for investigating morphological development and genomic adaptation in oomycete pathogens.


Assuntos
Genômica , Litchi/parasitologia , Phytophthora/classificação , Doenças das Plantas/parasitologia , Sequência de Bases , Frutas/parasitologia , Dados de Sequência Molecular , Filogenia , Phytophthora/genética , Phytophthora/fisiologia , Estrutura Terciária de Proteína , Análise de Sequência de DNA
17.
BMC Genomics ; 17: 354, 2016 05 16.
Artigo em Inglês | MEDLINE | ID: mdl-27185248

RESUMO

BACKGROUND: Sporisorium scitamineum causes the sugarcane smut disease, one of the most serious constraints to global sugarcane production. S. scitamineum possesses a sexual mating system composed of two mating-type loci, a and b locus. We previously identified and deleted the b locus in S. scitamineum, and found that the resultant SsΔMAT-1b mutant was defective in mating and pathogenicity. RESULTS: To further understand the function of b-mating locus, we carried out transcriptome analysis by comparing the transcripts of the mutant strain SsΔMAT-1b, from which the SsbE1 and SsbW1 homeodomain transcription factors have previously been deleted, with those from the wild-type MAT-1 strain. Also the transcripts from SsΔMAT-1b X MAT-2 were compared with those from wild-type MAT-1 X MAT-2 mating. A total of 209 genes were up-regulated (p < 0.05) in the SsΔMAT-1b mutant, compared to the wild-type MAT-1 strain, while 148 genes down-regulated (p < 0.05). In the mixture, 120 genes were up-regulated (p < 0.05) in SsΔMAT-1b X MAT-2, which failed to mate, compared to the wild-type MAT-1 X MAT-2 mating, and 271 genes down-regulated (p < 0.05). By comparing the up- and down-regulated genes in these two sets, it was found that 15 up-regulated and 37 down-regulated genes were common in non-mating haploid and mating mixture, which indeed could be genes regulated by b-locus. Furthermore, GO and KEGG enrichment analysis suggested that carbon metabolism pathway and stress response mediated by Hog1 MAPK signaling pathway were altered in the non-mating sets. CONCLUSIONS: Experimental validation results indicate that the bE/bW heterodimeric transcriptional factor, encoded by the b-locus, could regulate S. scitamineum sexual mating and/or filamentous growth via modulating glucose metabolism and Hog1-mediating oxidative response.


Assuntos
Basidiomycota/fisiologia , Meio Ambiente , Perfilação da Expressão Gênica , Reprodução Assexuada/genética , Transcriptoma , Metabolismo dos Carboidratos/genética , Biologia Computacional/métodos , Bases de Dados de Ácidos Nucleicos , Regulação Fúngica da Expressão Gênica , Genes Fúngicos Tipo Acasalamento , Sistema de Sinalização das MAP Quinases , Modelos Biológicos , Anotação de Sequência Molecular
18.
Mol Plant Pathol ; 17(9): 1398-1408, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-26814706

RESUMO

Dickeya zeae is a causal agent of rice root rot disease. The pathogen is known to produce a range of virulence factors, including phytotoxic zeamines and extracellular enzymes, but the mechanisms of virulence regulation remain vague. In this study, we identified a SlyA/MarR family transcription factor SlyA in D. zeae strain EC1. Disruption of slyA significantly decreased zeamine production, enhanced swimming and swarming motility, reduced biofilm formation and significantly decreased pathogenicity on rice. Quantitative polymerase chain reaction (qPCR) analysis confirmed the role of SlyA in transcriptional modulation of a range of genes associated with bacterial virulence. In trans expression of slyA in expI mutants recovered the phenotypes of motility and biofilm formation, suggesting that SlyA is downstream of the acylhomoserine lactone-mediated quorum sensing pathway. Taken together, the findings from this study unveil a key transcriptional regulatory factor involved in the modulation of virulence factor production and overall pathogenicity of D. zeae EC1.


Assuntos
Proteínas de Bactérias/metabolismo , Enterobacteriaceae/patogenicidade , Oryza/microbiologia , Toxinas Biológicas/metabolismo , Biofilmes , Parede Celular/metabolismo , Enterobacteriaceae/genética , Enterobacteriaceae/metabolismo , Genes de Plantas , Genoma Bacteriano , Germinação , Macrolídeos/metabolismo , Movimento , Mutação/genética , Poliaminas/metabolismo , Sementes/microbiologia , Transcrição Genética , Virulência
19.
Fungal Genet Biol ; 86: 1-8, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26563415

RESUMO

Sporisorium scitamineum is the causal agent of sugarcane smut, which is one of the most serious constraints to global sugarcane production. S. scitamineum and Ustilago maydis are two closely related smut fungi, that are predicted to harbor similar sexual mating processes/system. To elucidate the molecular basis of sexual mating in S. scitamineum, we identified and deleted the ortholog of mating-specific U. maydis locus b, in S. scitamineum. The resultant b-deletion mutant was defective in mating and pathogenicity in S. scitamineum. Furthermore, a functional b locus heterodimer could trigger filamentous growth without mating in S. scitamineum, and functionally replace the b locus in U. maydis in terms of triggering aerial filament production and forming solopathogenic strains, which do not require sexual mating prior to pathogenicity on the host plants.


Assuntos
Genes Fúngicos Tipo Acasalamento , Saccharum/microbiologia , Ustilaginales/genética , Ustilaginales/patogenicidade , Sequência de Aminoácidos , Dados de Sequência Molecular , Doenças das Plantas/microbiologia , Genética Reversa , Ustilaginales/crescimento & desenvolvimento , Ustilago/genética , Ustilago/patogenicidade , Virulência
20.
Sci Rep ; 5: 15719, 2015 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-26499339

RESUMO

Zeamines (ZMS), a class of polyamine-polyketide-nonribosomal peptide produced by bacterial isolate Dickeya zeae, were shown recently to be potent antibiotics against some bacterial pathogens. In this study, the results indicated that ZMS showed antifungal activity against Peronophythora litchii and other fungal pathogens. The activity of ZMS against the oomycete pathogen P. litchi, which causes the devastating litchi downy blight, was further investigated under in vitro and in vivo conditions. ZMS displayed potent inhibitory activity against the mycelial growth and sporangia germination of P. litchii. At a concentration of 2 µg/mL, about 99% of the sporangia germination was inhibited. Scanning electron microscopy and transmission electron microscopy analyses showed that treatment with ZMS could cause substantial damages to the oomycete endomembrane system. Furthermore, treatment of litchi fruits with ZMS solution significantly (P < 0.05) reduced the fruits decay and peel browning caused by P. litchii infection during storage at 28 °C. Taken together, our results provide useful clues on the antifungal mechanisms of ZMS, and highlight the promising potentials of ZMS as a fungicide, which in particular, may be useful for prevention and control of litchi fruits decay and browning caused by P. litchii infection during storage and transportation.


Assuntos
Enterobacteriaceae/química , Litchi/microbiologia , Macrolídeos/farmacologia , Poliaminas/farmacologia , Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Antifúngicos/isolamento & purificação , Antifúngicos/farmacologia , Germinação/efeitos dos fármacos , Macrolídeos/isolamento & purificação , Testes de Sensibilidade Microbiana , Phytophthora/efeitos dos fármacos , Poliaminas/isolamento & purificação , Esporângios/efeitos dos fármacos
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