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1.
J Basic Microbiol ; 59(11): 1092-1104, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31613011

RESUMO

Melanins are one of the great natural pigments produced by a wide variety of fungal species that promote fitness and cell survival in diverse hostile environments, including during mammalian infection. In this study, we sought to demonstrate the production of melanin in the conidia and hyphae of saprophytic fungi, including dematiaceous and hyaline fungi. We showed that a melanin-specific monoclonal antibody (MAb) avidly labeled the cell walls of hyphae and conidia, consistent with the presence of melanin in these structures, in 14 diverse fungal species. The conidia of saprophytic fungi were treated with proteolytic enzymes, denaturant, and concentrated hot acid to yield dark particles, which were shown to be stable free radicals, consistent with their identification as melanins. Samples obtained from patients with fungal keratitis due to Fusarium falciforme, Aspergillus fumigatus, Aspergillus flavus, Curvularia lunata, Exserohilum rostratum, or Fonsecaea pedrosoi were found to be intensely labeled by the melanin-specific MAb at the fungal hyphal cell walls. These results support the hypothesis that melanin is a common component that promotes survival under harsh conditions and facilitates fungal virulence. Increased understanding of the processes of melanization and the development of methods to interfere with pigment formation may lead to novel approaches to combat these complex pathogens that are associated with high rates of morbidity and mortality.


Assuntos
Fungos/metabolismo , Melaninas/biossíntese , Micoses/microbiologia , Anticorpos Monoclonais/imunologia , Parede Celular/metabolismo , Fungos/isolamento & purificação , Humanos , Hifas/isolamento & purificação , Hifas/metabolismo , Ceratite/microbiologia , Melaninas/imunologia , Esporos Fúngicos/isolamento & purificação , Esporos Fúngicos/metabolismo
3.
J Microbiol ; 57(10): 893-899, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31463784

RESUMO

Fungal development is regulated by a variety of transcription factors in Aspergillus nidulans. Previous studies demonstrated that the NF-κB type velvet transcription factors regulate certain target genes that govern fungal differentiation and cellular metabolism. In this study, we characterize one of the VosA/VelB-inhibited developmental genes called vidA, which is predicted to encode a 581-amino acid protein with a C2H2 zinc finger domain at the C-terminus. Levels of vidA mRNA are high during the early and middle phases of asexual development and decrease during the late phase of asexual development and asexual spore (conidium) formation. Deletion of either vosA or velB results in increased vidA mRNA accumulation in conidia, suggesting that vidA transcript accumulation in conidia is repressed by VosA and VelB. Phenotypic analysis demonstrated that deletion of vidA causes decreased colony growth, reduced production of asexual spores, and abnormal formation of sexual fruiting bodies. In addition, the vidA deletion mutant conidia contain more trehalose and ß-glucan than wild type. Overall, these results suggest that VidA is a putative transcription factor that plays a key role in governing proper fungal growth, asexual and sexual development, and conidia formation in A. nidulans.


Assuntos
Aspergillus nidulans/crescimento & desenvolvimento , Aspergillus nidulans/metabolismo , Proteínas Fúngicas/metabolismo , Fatores de Transcrição/metabolismo , Aspergillus nidulans/genética , Proteínas Fúngicas/genética , Deleção de Genes , Regulação da Expressão Gênica no Desenvolvimento , Regulação Fúngica da Expressão Gênica , Esporos Fúngicos/genética , Esporos Fúngicos/crescimento & desenvolvimento , Esporos Fúngicos/metabolismo , Fatores de Transcrição/genética , beta-Glucanas/metabolismo
4.
J Sci Food Agric ; 99(13): 5760-5770, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31162844

RESUMO

BACKGROUND: It has been reported that antagonistic microorganisms could effectively control the infection of Fusarium graminearum. However, there is limited information on the control of F. graminearum by Saccharomyces cerevisiae, while the possible control mechanisms involved through proteomic and transcriptomic techniques have also not been reported. RESULTS: The results of this study showed that S. cerevisiae Y-912 could significantly inhibit the growth of F. graminearum Fg1, and the spore germination rate and germ tube length of F. graminearum Fg1 were also significantly inhibited by S. cerevisiae Y-912. Proteomic analysis revealed that differentially expressed proteins which were made of some basic proteins and enzymes related to basal metabolism, such as glyceraldehyde-3-phosphate dehydrogenase (GAPDH), phosphoglycerate mutase (PGAM), enolase (ENO), fructose diphosphate aldolase (FBA) and so on, were all down-regulated. The transcriptomics of F. graminearum control by S. cerevisiae was also analyzed. CONCLUSION: The control mechanism of S. cerevisiae Y-912 on F. graminearum Fg1 was a very complex material and energy metabolic process in which the related proteins and genes involved in the glycolytic pathway, tricarboxylic acid (TCA) cycle and amino acid metabolism were all down-regulated. © 2019 Society of Chemical Industry.


Assuntos
Fusarium/genética , Saccharomyces cerevisiae/genética , Transcriptoma , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Fusarium/crescimento & desenvolvimento , Fusarium/metabolismo , Proteoma/genética , Proteoma/metabolismo , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/metabolismo , Esporos Fúngicos/genética , Esporos Fúngicos/crescimento & desenvolvimento , Esporos Fúngicos/metabolismo
5.
Genetics ; 212(4): 1241-1258, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31175227

RESUMO

The target of rapamycin (TOR) pathway is an evolutionarily conserved signal transduction system that governs a plethora of eukaryotic biological processes, but its role in Cryptococcus neoformans remains elusive. In this study, we investigated the TOR pathway by functionally characterizing two Tor-like kinases, Tor1 and Tlk1, in C. neoformans We successfully deleted TLK1, but not TOR1 TLK1 deletion did not result in any evident in vitro phenotypes, suggesting that Tlk1 is dispensable for the growth of C. neoformans We demonstrated that Tor1, but not Tlk1, is essential and the target of rapamycin by constructing and analyzing conditionally regulated strains and sporulation analysis of heterozygous mutants in the diploid strain background. To further analyze the Tor1 function, we constructed constitutive TOR1 overexpression strains. Tor1 negatively regulated thermotolerance and the DNA damage response, which are two important virulence factors of C. neoformans TOR1 overexpression reduced Mpk1 phosphorylation, which is required for cell wall integrity and thermoresistance, and Rad53 phosphorylation, which governs the DNA damage response pathway. Tor1 is localized to the cytoplasm, but enriched in the vacuole membrane. Phosphoproteomics and transcriptomics revealed that Tor1 regulates a variety of biological processes, including metabolic processes, cytoskeleton organization, ribosome biogenesis, and stress response. TOR inhibition by rapamycin caused actin depolarization in a Tor1-dependent manner. Finally, screening rapamycin-sensitive and -resistant kinase and transcription factor mutants revealed that the TOR pathway may crosstalk with a number of stress signaling pathways. In conclusion, our study demonstrates that a single Tor1 kinase plays pleiotropic roles in C. neoformans.


Assuntos
Cryptococcus neoformans/genética , Proteínas Fúngicas/genética , Pleiotropia Genética , Alvo Mecanístico do Complexo 1 de Rapamicina/genética , Termotolerância , Cryptococcus neoformans/metabolismo , Cryptococcus neoformans/fisiologia , Citoesqueleto/genética , Citoesqueleto/metabolismo , Proteínas Fúngicas/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Ribossomos/genética , Ribossomos/metabolismo , Transdução de Sinais , Esporos Fúngicos/genética , Esporos Fúngicos/metabolismo
6.
Microb Cell Fact ; 18(1): 87, 2019 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-31109314

RESUMO

BACKGROUND: Saccharomyces cerevisiae AN120 osw2∆ spores were used as a host with good resistance to unfavorable environment. This work was undertaken to develop a new yeast spore-encapsulation of Candida parapsilosis Glu228Ser/(S)-carbonyl reductase II and Bacillus sp. YX-1 glucose dehydrogenase for efficient chiral synthesis in organic solvents. RESULTS: The spore microencapsulation of E228S/SCR II and GDH in S. cerevisiae AN120 osw2∆ catalyzed (R)-phenylethanol in a good yield with an excellent enantioselectivity (up to 99%) within 4 h. It presented good resistance and catalytic functions under extreme temperature and pH conditions. The encapsulation produced several chiral products with over 70% yield and over 99% enantioselectivity in ethyl acetate after being recycled for 4-6 times. It increased substrate concentration over threefold and reduced the reaction time two to threefolds compared to the recombinant Escherichia coli containing E228S and glucose dehydrogenase. CONCLUSIONS: This work first described sustainable enantioselective synthesis without exogenous cofactors in organic solvents using yeast spore-microencapsulation of coupled alcohol dehydrogenases.


Assuntos
Oxirredutases do Álcool/metabolismo , Bacillus/metabolismo , Candida parapsilosis/metabolismo , Composição de Medicamentos/métodos , Glucose 1-Desidrogenase/metabolismo , Saccharomyces cerevisiae/metabolismo , Esporos Fúngicos/metabolismo , Solventes
7.
Nat Microbiol ; 4(9): 1443-1449, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31133754

RESUMO

Autocrine self-signalling via secreted peptides and cognate receptors regulates cell development in eukaryotes and is conserved from protozoans to mammals1,2. In contrast, secreted peptides from higher fungi have been traditionally associated with paracrine non-self-signalling during sexual reproduction3. For example, cells of the model fungus Saccharomyces cerevisiae fall into two distinct mating types (MAT), which produce either a- or α-pheromone and the cognate receptors Ste2 or Ste3, respectively4. Inappropriate autocrine pheromone signalling (APS) during mating is prevented by downregulation of the self-pheromone receptor4,5 and by a-type cell-specific cleavage of α-pheromone through the protease Bar1 (refs. 6-8). While APS can be artificially induced by manipulation of the pheromone secrete-and-sense circuit7,9-11, its natural occurrence in ascomycete fungi has not been described. Here, we show that Fusarium oxysporum-a devastating plant pathogen that lacks a known sexual cycle12-co-expresses both pheromone-receptor pairs, resulting in autocrine regulation of developmental programmes other than mating. We found that unisexual populations of MAT1-1 cells (α-type idiomorphs13) secrete and sense both a- and α-pheromone, and that their perception requires the cognate receptors and conserved elements of the cell wall integrity mitogen-activated protein kinase cascade. We further show that F. oxysporum uses APS to regulate spore germination in a cell-density-dependent manner, whereby the α-Ste2 interaction leads to repression of conidial germination while the a-Ste3 interaction relieves repression. Our results reveal the existence of a regulatory function for peptide pheromones in the quorum-sensing-mediated control of fungal development.


Assuntos
Comunicação Autócrina/fisiologia , Fusarium/fisiologia , Feromônios/metabolismo , Receptores de Feromonas/metabolismo , Ácido Aspártico Proteases/genética , Ácido Aspártico Proteases/metabolismo , Parede Celular/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Fusarium/crescimento & desenvolvimento , Hifas/crescimento & desenvolvimento , Hifas/metabolismo , Sistema de Sinalização das MAP Quinases/genética , Feromônios/genética , Doenças das Plantas/microbiologia , Percepção de Quorum , Receptores de Feromonas/genética , Esporos Fúngicos/crescimento & desenvolvimento , Esporos Fúngicos/metabolismo
8.
J Agric Food Chem ; 67(22): 6212-6221, 2019 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-31099566

RESUMO

Common soil fungi, Aspergillus flavus and Aspergillus parasiticus, are opportunistic pathogens that invade preharvest peanut seeds. These fungi often produce carcinogenic aflatoxins that pose a threat to human and animal health through food chains and cause significant economic losses worldwide. Detection of aflatoxins and further processing of crops are mandated to ensure that contaminated agricultural products do not enter food channels. Under favorable conditions, the fungus-challenged peanut seeds produce phytoalexins, structurally related stilbenoids, capable of retarding fungal development. The purpose of the present study was to evaluate the potential influence of peanut phytoalexins on fungal development and aflatoxin formation in the course of peanut-fungus interaction. The present research revealed that during such interaction, aflatoxin formation was completely suppressed in A. flavus and A. parasiticus strains tested, when low concentrations of spores were introduced to wounded preincubated peanuts. In most of the experiments, when fungal spore concentrations were 2 orders of magnitude higher, the spores germinated and produced aflatoxins. Of all experimental seeds that showed fungal growth, 57.7% were aflatoxin-free after 72 h of incubation. The research provided new knowledge on the aflatoxin/phytoalexin formation in the course of peanut-fungus interaction.


Assuntos
Aflatoxinas/biossíntese , Arachis/microbiologia , Aspergillus/metabolismo , Sementes/química , Estilbenos/farmacologia , Arachis/química , Arachis/metabolismo , Aspergillus/efeitos dos fármacos , Aspergillus/crescimento & desenvolvimento , Interações Hospedeiro-Parasita , Doenças das Plantas/microbiologia , Sementes/metabolismo , Sementes/microbiologia , Sesquiterpenos/metabolismo , Sesquiterpenos/farmacologia , Esporos Fúngicos/efeitos dos fármacos , Esporos Fúngicos/crescimento & desenvolvimento , Esporos Fúngicos/metabolismo , Estilbenos/metabolismo
9.
J Basic Microbiol ; 59(6): 609-620, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30980724

RESUMO

Revegetation is widely used to enhance degraded topsoil recovery with the enhancements of soil nutrient accumulation and soil structure stabilization. Arbuscular mycorrhizal fungi (AMF) are important for the allocation of carbon into the soil and the formation of soil aggregates. Thus, we hypothesized that AMF could construct more niches for other microbes during revegetation, making AMF keystone taxa of soil. Soil fungal and bacterial communities were investigated under a revegetation experiment and correlation networks between soil fungi and bacteria were constructed. Simultaneously, the plant growth level, soil properties and structure, and soil microbial carbon decomposition abilities were measured. The results revealed that AMF were the most central fungi at the phylum (degree = 3), class (degree = 11), and family (degree = 15) levels. The reads number of AMF were positively correlated with both fungal (R2 = 0.431, P < 0.001) and bacterial (R2 = 0.106, P = 0.044) richness. Higher colonization of AMF in roots and/or more AMF extraradical mycelium and spores in soil indicated a better plant growth, more stable soil aggregates, and a higher carbon decomposition ratio. Our results highlight that AMF are keystone taxa in revegetation, as they play significant roles in enhancing the recovery of the belowground microbiome diversity, soil structure stability, and nutrients cycling. The positive roles of AMF in revegetation support the application of AMF in ecosystem recovery.


Assuntos
Recuperação e Remediação Ambiental , Microbiota , Micorrizas/fisiologia , Microbiologia do Solo , Bactérias/classificação , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Bactérias/metabolismo , Carbono/metabolismo , Fungos/classificação , Fungos/genética , Fungos/crescimento & desenvolvimento , Fungos/metabolismo , Micélio/crescimento & desenvolvimento , Micélio/metabolismo , Micorrizas/classificação , Micorrizas/crescimento & desenvolvimento , Micorrizas/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Poaceae/crescimento & desenvolvimento , Poaceae/microbiologia , Solo/química , Esporos Fúngicos/crescimento & desenvolvimento , Esporos Fúngicos/metabolismo , Tibet
10.
J Agric Food Chem ; 67(17): 4868-4875, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30995033

RESUMO

The rare sugar l-ribulose is produced from the abundant sugar l-arabinose by enzymatic conversion. An l-arabinose isomerase (AI) from Geobacillus thermodenitrificans was efficiently expressed and encapsulated in Saccharomyces cerevisiae spores. Deletion of the yeast OSW2 gene, which causes a mild defect in the integrity of the spore wall, substantially improved the activity of encapsulated AI, without damaging its superior enzymatic properties of thermostability, pH tolerance,and resistance toward SDS and proteinase treatments. In a 10 mL reaction, 100 mg of dry AI encapsulated in spores produced 250 mg of l-ribulose from 1 g of l-arabinose, indicating a 25% conversion rate. Notably, the product of l-ribulose was directly purified from the reaction solution with an approximately 91% recovery using a Ca2+ ion exchange column. Our results describe not only a facile approach for the production of l-ribulose but also a useful strategy for the enzymatic conversion of rare sugars in "Izumoring".


Assuntos
Aldose-Cetose Isomerases/química , Aldose-Cetose Isomerases/metabolismo , Geobacillus stearothermophilus/enzimologia , Pentoses/metabolismo , Saccharomyces cerevisiae/metabolismo , Esporos Fúngicos/metabolismo , Aldose-Cetose Isomerases/genética , Arabinose/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Estabilidade Enzimática , Concentração de Íons de Hidrogênio , Saccharomyces cerevisiae/genética , Esporos Fúngicos/genética
11.
Food Microbiol ; 82: 551-559, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31027818

RESUMO

Moldy food products that are not subject to pathogenic bacterial contamination could be trimmed by consumers to remove fungal mycelium before consumption. However, prior to giving such recommendations to consumers, it is necessary to evaluate potential mycotoxin migration in these products. This study aimed at quantifying citrinin (CIT) and ochratoxin A (OTA) accumulation and migration in a French semi-hard Comté cheese after artificial inoculation with a CIT- and OTA-producing Penicillium verrucosum strain. At 8 °C, CIT and OTA production started after 14 days and 28 days incubation, respectively; while at 20 °C, both mycotoxins were produced from day 7. At 20 °C, maximum CIT concentration, about 50000 ng/g, was 20 fold that at 8 °C. Regardless of temperature, maximum OTA concentration was about 4000 ng/g cheese. Maximum concentrations were obtained in the upper part of the cheese, but depending on incubation time, mycotoxins were detected up to 1.6 cm in depth. As long as only white mycelium developed on the cheese surface, trimming can be acceptable, but a blue mold color (due to fungal sporulation) was associated with the accumulation of significant amounts of mycotoxins so the product should be discarded.


Assuntos
Queijo/microbiologia , Citrinina/biossíntese , Microbiologia de Alimentos , Ocratoxinas/biossíntese , Penicillium/metabolismo , Queijo/análise , Citrinina/análise , Inocuidade dos Alimentos , França , Micotoxinas/análise , Micotoxinas/biossíntese , Ocratoxinas/análise , Penicillium/crescimento & desenvolvimento , Penicillium/isolamento & purificação , Esporos Fúngicos/crescimento & desenvolvimento , Esporos Fúngicos/isolamento & purificação , Esporos Fúngicos/metabolismo , Temperatura Ambiente
12.
mBio ; 10(2)2019 04 09.
Artigo em Inglês | MEDLINE | ID: mdl-30967462

RESUMO

The filamentous fungus Alternaria alternata is a common postharvest contaminant of food and feed, and some strains are plant pathogens. Many processes in A. alternata are triggered by light. Interestingly, blue light inhibits sporulation, and red light reverses the effect, suggesting interactions between light-sensing systems. The genome encodes a phytochrome (FphA), a white collar 1 (WC-1) orthologue (LreA), an opsin (NopA), and a cryptochrome (CryA) as putative photoreceptors. Here, we investigated the role of FphA and LreA and the interplay with the high-osmolarity glycerol (HOG) mitogen-activated protein (MAP) kinase pathway. We created loss-of function mutations for fphA, lreA, and hogA using CRISPR-Cas9 technology. Sporulation was reduced in all three mutant strains already in the dark, suggesting functions of the photoreceptors FphA and LreA independent of light perception. Germination of conidia was delayed in red, blue, green, and far-red light. We found that light induction of ccgA (clock-controlled gene in Neurospora crassa and light-induced gene in Aspergillus nidulans) and the catalase gene catA depended on FphA, LreA, and HogA. Light induction of ferA (a putative ferrochelatase gene) and bliC (bli-3, light regulated, unknown function) required LreA and HogA but not FphA. Blue- and green-light stimulation of alternariol formation depended on LreA. A lack of FphA or LreA led to enhanced resistance toward oxidative stress due to the upregulation of catalases and superoxide dismutases. Light activation of FphA resulted in increased phosphorylation and nuclear accumulation of HogA. Our results show that germination, sporulation, and secondary metabolism are light regulated in A. alternata with distinct and overlapping roles of blue- and red-light photosensors.IMPORTANCE Light controls many processes in filamentous fungi. The study of light regulation in a number of model organisms revealed an unexpected complexity. Although the molecular components for light sensing appear to be widely conserved in fungal genomes, the regulatory circuits and the sensitivity of certain species toward specific wavelengths seem different. In N. crassa, most light responses are triggered by blue light, whereas in A. nidulans, red light plays a dominant role. In Alternaria alternata, both blue and red light appear to be important. In A. alternata, photoreceptors control morphogenetic pathways, the homeostasis of reactive oxygen species, and the production of secondary metabolites. On the other hand, high-osmolarity sensing required FphA and LreA, indicating a sophisticated cross talk between light and stress signaling.


Assuntos
Alternaria/crescimento & desenvolvimento , Alternaria/efeitos da radiação , Luz , Fotorreceptores Microbianos/metabolismo , Fitocromo/metabolismo , Esporos Fúngicos/crescimento & desenvolvimento , Esporos Fúngicos/efeitos da radiação , Alternaria/genética , Alternaria/metabolismo , Regulação Fúngica da Expressão Gênica/efeitos da radiação , Técnicas de Inativação de Genes , Redes Reguladoras de Genes , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Transdução de Sinais , Esporos Fúngicos/genética , Esporos Fúngicos/metabolismo
13.
Genetics ; 212(1): 93-110, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30918007

RESUMO

Sk-2 is a meiotic drive element that was discovered in wild populations of Neurospora fungi over 40 years ago. While early studies quickly determined that Sk-2 transmits itself through sexual reproduction in a biased manner via spore killing, the genetic factors responsible for this phenomenon have remained mostly unknown. Here, we identify and characterize rfk-1, a gene required for Sk-2-based spore killing. The rfk-1 gene contains four exons, three introns, and two stop codons, the first of which undergoes RNA editing to a tryptophan codon during sexual development. Translation of an unedited rfk-1 transcript in vegetative tissue is expected to produce a 102-amino acid protein, whereas translation of an edited rfk-1 transcript in sexual tissue is expected to produce a protein with 130 amino acids. These findings indicate that unedited and edited rfk-1 transcripts exist and that these transcripts could have different roles with respect to the mechanism of meiotic drive by spore killing. Regardless of RNA editing, spore killing only succeeds if rfk-1 transcripts avoid silencing caused by a genome defense process called meiotic silencing by unpaired DNA (MSUD). We show that rfk-1's MSUD avoidance mechanism is linked to the genomic landscape surrounding the rfk-1 gene, which is located near the Sk-2 border on the right arm of chromosome III. In addition to demonstrating that the location of rfk-1 is critical to spore-killing success, our results add to accumulating evidence that MSUD helps protect Neurospora genomes from complex meiotic drive elements.


Assuntos
Proteínas Fúngicas/metabolismo , Meiose , Neurospora/metabolismo , Edição de RNA , Esporos Fúngicos/metabolismo , Proteínas Fúngicas/genética , Regulação Fúngica da Expressão Gênica , Neurospora/genética , Neurospora/fisiologia , Esporos Fúngicos/genética
14.
Arch Microbiol ; 201(6): 807-816, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30874825

RESUMO

Rice blast, caused by Magnaporthe oryzae, is a serious threat to global rice production. In recent years, many pathogenicity genes of M. oryzae have been identified, although most of their functions remain unknown. In this study, we report the synergistic deletion of RGS1 and COS1 that may reduce the pathogenicity of M. oryzae. The investigation involved comparing ΔMorgs1, ΔMocos1, and ΔMorgs1/ΔMocos1 mutants. The ΔMorgs1/ΔMocos1 mutant showed a weak reduction in vegetative growth, and the colonies displayed fewer and smoother aerial hyphae. The ΔMorgs1/ΔMocos1 mutant exhibited delayed appressorium-like structure formation and 'low pathogenicity' on detached rice seedling leaves when compared with ΔMocos1. Moreover, the melanin content of the single and double mutants was remarkably lower than that of the WT type. Thus, our results indicate that the synergy between RGS1 and COS1 may be crucial in the pathogenicity of M. oryzae.


Assuntos
Proteínas Fúngicas/genética , Deleção de Genes , Magnaporthe/genética , Magnaporthe/patogenicidade , Oryza/microbiologia , Doenças das Plantas/microbiologia , Proteínas Fúngicas/metabolismo , Regulação Fúngica da Expressão Gênica , Hifas/genética , Hifas/crescimento & desenvolvimento , Hifas/metabolismo , Hifas/patogenicidade , Magnaporthe/crescimento & desenvolvimento , Magnaporthe/metabolismo , Plântula/microbiologia , Esporos Fúngicos/genética , Esporos Fúngicos/crescimento & desenvolvimento , Esporos Fúngicos/metabolismo , Esporos Fúngicos/patogenicidade , Virulência
15.
J Agric Food Chem ; 67(15): 4200-4213, 2019 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-30916945

RESUMO

In Aspergillus, the cyclic adenosine monophosphate (cAMP) signaling modulates asexual development and mycotoxin biosynthesis. Here, we characterize the cyclase-associated protein Cap in the pathogenic fungus Aspergillus flauvs. The cap disruption mutant exhibited dramatic reduction in hyphal growth, conidiation, and spore germination, while an enhanced production of the sclerotia was observed in this mutant. Importantly, the cap gene was found to be important for mycotoxin biosynthesis and virulence. The domain deletion study demonstrated that each domain played an important role for the Cap protein in regulating cAMP/protein kinase A (PKA) signaling, while only P1 and CARP domains were essential for the full function of Cap. The phosphorylation of Cap at S35 was identified in A. flavus, which was found to play a negligible role for the function of Cap. Overall, our results indicated that Cap with multiple domains engages in mycotoxin production and fungal pathogenicity, which could be designed as potential control targets for preventing this fungal pathogen.


Assuntos
Aflatoxinas/biossíntese , Aspergillus flavus/metabolismo , Proteínas Fúngicas/química , Proteínas Fúngicas/metabolismo , Aspergillus flavus/enzimologia , Aspergillus flavus/genética , Aspergillus flavus/patogenicidade , AMP Cíclico/metabolismo , Proteínas Fúngicas/genética , Regulação Fúngica da Expressão Gênica , Doenças das Plantas/microbiologia , Domínios Proteicos , Esporos Fúngicos/enzimologia , Esporos Fúngicos/genética , Esporos Fúngicos/crescimento & desenvolvimento , Esporos Fúngicos/metabolismo , Virulência , Zea mays/microbiologia
16.
mBio ; 10(2)2019 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-30914504

RESUMO

Fungal spores germinate and undergo vegetative growth, leading to either asexual or sexual reproductive dispersal. Previous research has indicated that among developmental regulatory genes, expression is conserved across nutritional environments, whereas pathways for carbon and nitrogen metabolism appear highly responsive-perhaps to accommodate differential nutritive processing. To comprehensively investigate conidial germination and the adaptive life history decision-making underlying these two modes of reproduction, we profiled transcription of Neurospora crassa germinating on two media: synthetic Bird medium, designed to promote asexual reproduction; and a natural maple sap medium, on which both asexual reproduction and sexual reproduction manifest. A later start to germination but faster development was observed on synthetic medium. Metabolic genes exhibited altered expression in response to nutrients-at least 34% of the genes in the genome were significantly downregulated during the first two stages of conidial germination on synthetic medium. Knockouts of genes exhibiting differential expression across development altered germination and growth rates, as well as in one case causing abnormal germination. A consensus Bayesian network of these genes indicated especially tight integration of environmental sensing, asexual and sexual development, and nitrogen metabolism on a natural medium, suggesting that in natural environments, a more dynamic and tentative balance of asexual and sexual development may be typical of N. crassa colonies.IMPORTANCE One of the most remarkable successes of life is its ability to flourish in response to temporally and spatially varying environments. Fungi occupy diverse ecosystems, and their sensitivity to these environmental changes often drives major fungal life history decisions, including the major switch from vegetative growth to asexual or sexual reproduction. Spore germination comprises the first and simplest stage of vegetative growth. We examined the dependence of this early life history on the nutritional environment using genome-wide transcriptomics. We demonstrated that for developmental regulatory genes, expression was generally conserved across nutritional environments, whereas metabolic gene expression was highly labile. The level of activation of developmental genes did depend on current nutrient conditions, as did the modularity of metabolic and developmental response network interactions. This knowledge is critical to the development of future technologies that could manipulate fungal growth for medical, agricultural, or industrial purposes.


Assuntos
Carbono/metabolismo , Neurospora crassa/crescimento & desenvolvimento , Neurospora crassa/metabolismo , Nitrogênio/metabolismo , Esporos Fúngicos/crescimento & desenvolvimento , Esporos Fúngicos/metabolismo , Meios de Cultura/química , Perfilação da Expressão Gênica , Regulação Fúngica da Expressão Gênica , Redes e Vias Metabólicas/genética , Neurospora crassa/genética
17.
Adv Mater ; 31(16): e1900009, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30843629

RESUMO

Tailored construction of advanced carbon hosts is playing a great role in the development of high-performance lithium-sulfur batteries (LSBs). Herein, a novel N,P-codoped trichoderma spore carbon (TSC) with a bowl structure, prepared by a "trichoderma bioreactor" and annealing process is reported. Moreover, TSC shows excellent compatibility with conductive niobium carbide (NbC), which is in situ implanted into the TSC matrix in the form of nanoparticles forming a highly porous TSC/NbC host. Importantly, NbC plays a dual role in TSC for not only pore formation but also enhancement of conductivity. Excitingly, the sulfur can be well accommodated in the TSC/NbC host forming a high-performance TSC/NbC-S cathode, which exhibits greatly enhanced rate performance (810 mAh g-1 at 5 C) and long cycling life (937.9 mAh g-1 at 0.1 C after 500 cycles), superior to TSC-S and other carbon/S counterparts due to the larger porosity, higher conductivity, and better synergetic trapping effect for the soluble polysulfide intermediate. The synergetic work of porous the conductive architecture, heterodoped N&P polar sites in TSC and polar conductive NbC provides new opportunities for enhancing physisorption and chemisorption of polysulfides leading to higher capacity and better rate capability.


Assuntos
Nióbio/química , Esporos Fúngicos/metabolismo , Enxofre/química , Trichoderma/metabolismo , Fontes de Energia Bioelétrica , Condutividade Elétrica , Técnicas Eletroquímicas , Eletrodos , Nióbio/metabolismo , Porosidade , Sulfetos/química , Termodinâmica
18.
J Plant Res ; 132(3): 405-417, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30864048

RESUMO

Previous studies have already highlighted the correlation between Sporisorium scitamineum pathogenicity and sugarcane polyamine accumulation. It was shown that high infectivity correlates with an increase in the amount of spermidine, spermine and cadaverine conjugated to phenols in the sensitive cultivars whereas resistant plants mainly produce free putrescine. However, these previous studies did not clarify the role of these polyamides in the disorders caused to the plant. Therefore, the purpose of this research is to clarify the effect of polyamines on the development of smut disease. In this paper, commercial polyamines were firstly assayed on smut teliospores germination. Secondly, effects were correlated to changes in endogenous polyamines after contact with defense sugarcane glycoproteins. Low concentrations of spermidine significantly activated teliospore germination, while putrescine had no activating effect on germination. Interestingly, it was observed that the diamine caused nuclear decondensation and breakage of the teliospore cell wall whereas the treatment of teliospores with spermidine did not induce nuclear decondensation or cell wall breakdown. Moreover, the number of polymerized microtubules increased in the presence of 7.5 mM spermidine but it decreased with putrescine which indicates that polyamines effects on Sporisorium scitamineum teliospore germination could be mediated through microtubules interaction. An increased production of polyamines in smut teliospores has been related to sugarcane resistance to the disease. Teliospores incubation with high molecular mass glycoproteins (HMMG) from the uninoculated resistant variety of sugarcane, Mayari 55-14, caused an increase of the insoluble fraction of putrescine, spermidine and spermine inside the teliospore cells. Moreover, the level of the soluble fraction of spermidine (S fraction) increased inside teliospores and the excess was released to the medium. The HMMG glycoproteins purified from Mayarí 55-14 plants previously inoculated with the pathogen significantly increased the levels of both retained and secreted soluble putrescine and spermidine. Polyamines levels did not increase in teliospores after incubation with HMMG produced by non resistant variety Barbados 42231 which could be related to the incapacity of these plants to defend themselves against smut disease. Thus, a hypothesis about the role of polyamines in sugarcane-smut interaction is explained.


Assuntos
Poliaminas Biogênicas/metabolismo , Glicoproteínas/metabolismo , Imunidade Vegetal , Saccharum/microbiologia , Esporos Fúngicos/metabolismo , Ustilaginales/metabolismo , Poliaminas Biogênicas/fisiologia , Glicoproteínas/fisiologia , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Putrescina/metabolismo , Putrescina/fisiologia , Saccharum/metabolismo , Espermidina/metabolismo , Espermidina/fisiologia , Espermina/metabolismo , Espermina/fisiologia , Ustilaginales/fisiologia
19.
ISME J ; 13(6): 1484-1496, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30745572

RESUMO

Recent molecular evidence suggests a global distribution of marine fungi; however, the ecological relevance and corresponding biological contributions of fungi to marine ecosystems remains largely unknown. We assessed fungal biomass from the open Arctic Ocean by applying novel biomass conversion factors from cultured isolates to environmental sterol and CARD-FISH data. We found an average of 16.54 nmol m-3 of ergosterol in sea ice and seawater, which corresponds to 1.74 mg C m-3 (444.56 mg C m-2 in seawater). Using Chytridiomycota-specific probes, we observed free-living and particulate-attached cells that averaged 34.07 µg C m-3 in sea ice and seawater (11.66 mg C m-2 in seawater). Summed CARD-FISH and ergosterol values approximate 1.77 mg C m-3 in sea ice and seawater (456.23 mg C m-2 in seawater), which is similar to biomass estimates of other marine taxa generally considered integral to marine food webs and ecosystem processes. Using the GeoChip microarray, we detected evidence for fungal viruses within the Partitiviridae in sediment, as well as fungal genes involved in the degradation of biomass and the assimilation of nitrate. To bridge our observations of fungi on particulate and the detection of degradative genes, we germinated fungal conidia in zooplankton fecal pellets and germinated fungal conidia after 8 months incubation in sterile seawater. Ultimately, these data suggest that fungi could be as important in oceanic ecosystems as they are in freshwater environments.


Assuntos
Fungos/isolamento & purificação , Água do Mar/microbiologia , Regiões Árticas , Biomassa , Ecossistema , Cadeia Alimentar , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Fungos/classificação , Fungos/genética , Fungos/crescimento & desenvolvimento , Camada de Gelo/microbiologia , Oceanos e Mares , Esporos Fúngicos/genética , Esporos Fúngicos/crescimento & desenvolvimento , Esporos Fúngicos/metabolismo
20.
Mol Microbiol ; 111(5): 1245-1262, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30746783

RESUMO

Ascospores are the primary inoculum in Fusarium graminearum. Interestingly, 70 of its genes have premature stop codons (PSC) and require A-to-I editing during sexual reproduction to encode full-length proteins, including the ortholog of yeast Ama1, a meiosis-specific activator of APC/C. In this study, we characterized the function of FgAMA1 and its PSC editing. FgAMA1 was specifically expressed during sexual reproduction. The Fgama1 mutant was normal in growth and perithecium formation but defective in ascospogenesis. Instead of forming four-celled, uninucleate ascospores, Fgama1 mutant produced oval, single-celled, binucleated ascospores by selfing. Some mutant ascospores began to bud and underwent additional mitosis inside asci. Expression of the wild-type or edited FgAMA1 but not the uneditable allele complemented Fgama1. In the Fgama1 x mat-1-1 outcross, over 60% of the asci had eight Fgama1 or intermediate (elongated but single-celled) ascospores, suggesting efficient meiotic silencing of unpaired FgAMA1. Deletion of FgPAL1, one of the genes upregulated in Fgama1 also resulted in defects in ascospore morphology and budding. Overall, our results showed that FgAMA1 is dispensable for meiosis but important for ascospore formation and discharge. In F. graminearum, whereas some of its targets are functional during meiosis, FgAma1 may target other proteins that function after spore delimitation.


Assuntos
Proteínas Fúngicas/genética , Fusarium/genética , Meiose , Esporos Fúngicos/crescimento & desenvolvimento , Proteínas Fúngicas/metabolismo , Fusarium/crescimento & desenvolvimento , Regulação Fúngica da Expressão Gênica , Mutação , Esporos Fúngicos/genética , Esporos Fúngicos/metabolismo , Regulação para Cima
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