Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 325
Filtrar
1.
Arch Virol ; 166(11): 3233-3237, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34535823

RESUMO

The entomopathogenic fungus Beauveria bassiana is used worldwide for biological control of insects. Seven dsRNA segments were detected in a single B. bassiana strain, RCEF1446. High-throughput sequencing indicated the presence of three mycoviruses in RCEF1446. Two were identified as the known mycoviruses Beauveria bassiana victorivirus 1 and Beauveria bassiana polymycovirus 1, and the novel mycovirus was designated as "Beauveria bassiana bipartite mycovirus 1" (BbBV1). The complete sequence of the BbBV1 is described here. The mycovirus contains two dsRNA segments. The RNA 1 (dsRNA 4) of BbBV1 is 2,026 bp in length, encoding a RNA-dependent RNA polymerase (RdRp) (68.54 kDa), while the RNA 2 (dsRNA 6) is 1,810 bp in length, encoding a hypothetical protein (35.55 kDa) with unknown function. Moreover, the amino acid sequence of RdRp showed the highest sequence identity of 62.31% to Botryosphaeria dothidea bipartite mycovirus 1. Phylogenetic analysis based on RdRp sequences revealed that BbBV1 represents a distinct lineage of unassigned dsRNA mycoviruses infecting fungi.


Assuntos
Beauveria/virologia , Vírus de RNA de Cadeia Dupla/genética , Micovírus/genética , Genoma Viral , Filogenia , Beauveria/patogenicidade , RNA de Cadeia Dupla , RNA Polimerase Dependente de RNA/genética , Proteínas Virais/genética
2.
Int J Mol Sci ; 22(15)2021 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-34360963

RESUMO

The insect immune response is initiated by the recognition of invading microorganisms. Peptidoglycan recognition proteins (PGRPs) function primarily as pattern recognition receptors by specifically binding to peptidoglycans expressed on microbial surfaces. We cloned a full-length cDNA for a PGRP from the Asian corn borer Ostrinia furnacalis (Guenée) and designated it as PGRP1. PGRP1 mRNA was mainly detected in the fat bodies and hemocytes. Its transcript levels increased significantly upon bacterial and fungal challenges. Purified recombinant PGRP1 exhibited binding activity to the gram-positive Micrococcus luteus, gram-negative Escherichia coli, entomopathogenic fungi Beauveria bassiana, and yeast Pichia pastoris. The binding further induced their agglutination. Additionally, PGRP1 preferred to bind to Lys-type peptidoglycans rather than DAP-type peptidoglycans. The addition of recombinant PGRP1 to O. furnacalis plasma resulted in a significant increase in phenoloxidase activity. The injection of recombinant PGRP1 into larvae led to a significantly increased expression of several antimicrobial peptide genes. Taken together, our results suggest that O. furnacalis PGRP1 potentially recognizes the invading microbes and is involved in the immune response in O. furnacalis.


Assuntos
Imunidade Inata , Proteínas de Insetos/metabolismo , Lepidópteros/genética , Peptidoglicano/metabolismo , Animais , Beauveria/patogenicidade , Corpo Adiposo/metabolismo , Hemócitos/metabolismo , Proteínas de Insetos/genética , Lepidópteros/imunologia , Lepidópteros/microbiologia , Micrococcus luteus/patogenicidade , Monofenol Mono-Oxigenase/metabolismo , Peptidoglicano/genética , Proteínas Citotóxicas Formadoras de Poros/genética , Proteínas Citotóxicas Formadoras de Poros/metabolismo , Saccharomycetales/patogenicidade
3.
Sci Rep ; 11(1): 13915, 2021 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-34230511

RESUMO

Beauveria bassiana is one of the most widely studied and used entomopathogenic fungus as biopesticide. In the biological control of pests, B. bassiana will persist in the soil after application, and will inevitably contact with earthworms, especially the epigeic earthworm species. So, what are the effects of earthworm and its epidermal mucus on the activity of B. bassiana? We employed the epigeic earthworm Eisenia fetida, B. bassiana TST05 strain, and the insect Atrijuglans hetaohei mature larvae to study the impact of earthworm epidermal mucus on the vitality and pathogenicity of B. bassiana to insect. Methods included scanning electron microscope observation, detection of spore germination, fungal extracellular enzyme activity, and infection testing to A. hetaohei. The results showed that the B. bassiana spores may attach to the cuticle of E. fetida but they could be covered by the epidermal mucus and became rough and shrunken. After treatment with the epidermal mucus, the spore germination and extracellular enzymes of B. bassiana was significantly inhibited. Inoculation of A. hetaohei larvae with a mixture of B. bassiana and mucus showed that the mucus could reduce the pathogenicity of B. bassiana to the insect, resulting in a slower disease course and lower mortality. It was concluded that the epidermal mucus of the earthworm E. fetida can inhibit the activity of B. bassiana, as well as the infectivity and pathogenicity of fungus to target insects. However, after treatment with epidermal mucus the surviving B. bassiana still had certain infectivity to insects. This is of great significance for the application of B. bassiana in biological control of pests.


Assuntos
Beauveria/patogenicidade , Epiderme/química , Muco/química , Oligoquetos/química , Animais , Beauveria/crescimento & desenvolvimento , Beauveria/ultraestrutura , Espaço Extracelular/enzimologia , Larva/microbiologia , Esporos Fúngicos/fisiologia
4.
Mol Immunol ; 135: 204-216, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33930715

RESUMO

Beauveria bassiana is a harmful pathogen to the economically important insect silkworm, always causes serious disease to the silkworm, which results in great losses to the sericulture industry. In order to explore the silkworm (Bombyx mori) response to B. bassiana infection, differential proteomes of the silkworm responsive to B. bassiana infection were identified with isobaric tags for relative and absolute quantitation (iTRAQ) at the different stage of the 3rd instar silkworm larvae. Among the 5040 proteins identified with confidence level of ≥95 %, total 937 proteins were differentially expressed, of which 488 proteins were up-regulated and 449 proteins were down-regulated. 23, 15, 250, 649 differentially expressed proteins (DEPs) were reliably quantified by iTRAQ analysis in the B. bassiana infected larvae at 18, 24, 36, 48 h post infection (hpi) respectively. Based on GO annotations, 6, 4, 128, 316 DEPs were involved in biological processes, 12, 5, 143, 376 DEPs were involved in molecular functions, and 6, 3, 108, 256 DEPs were involved in cell components at 18, 24, 36, 48 hpi respectively. KEGG pathway analysis displayed that 18, 12, 210, 548 DEPs separately participated in 63, 35, 201, 264 signal transduction pathways at different time of infection, and moreover a higher proportion of DEPs involved in metabolic pathways. The cluster analysis on the DEPs of different infection stages distinguished a co-regulated DEP, lysozyme precursor, which was up-regulated at both the mRNA level and the protein level, indicating that the lysozyme protein kept playing an important role in defending the silkworm against B. bassiana infection. This was the first report using an iTRAQ approach to analyze proteomes of the whole silkworm against B. bassiana infection, which contributes to better understanding the defense mechanisms of silkworm to B. bassiana infection and provides important experimental data for the identification of key factors involved in the interaction between the pathogenic fungus and its host.


Assuntos
Beauveria/imunologia , Bombyx/imunologia , Bombyx/microbiologia , Imunidade Inata/imunologia , Muramidase/metabolismo , Animais , Beauveria/patogenicidade , Bombyx/metabolismo , Regulação da Expressão Gênica/imunologia , Larva/metabolismo , Larva/microbiologia , Muramidase/biossíntese , Muramidase/genética , Proteoma/análise , Proteômica/métodos , Transdução de Sinais , Espectrometria de Massas em Tandem/métodos
5.
PLoS One ; 16(3): e0249350, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33788872

RESUMO

The p53-like transcription factor (TF) NDT80 plays a vital role in the regulation of pathogenic mechanisms and meiosis in certain fungi. However, the effects of NDT80 on entomopathogenic fungi are still unknown. In this paper, the NDT80 orthologue BbTFO1 was examined in Beauveria bassiana, a filamentous entomopathogenic fungus, to explore the role of an NDT80-like protein for fungal pest control potential. Disruption of BbTFO1 resulted in impaired resistance to oxidative stress (OS) in a growth assay under OS and a 50% minimum inhibitory concentration experiment. Intriguingly, the oxidation resistance changes were accompanied by transcriptional repression of the two key antioxidant enzyme genes cat2 and cat5. ΔBbTFO1 also displayed defective conidial germination, virulence and heat resistance. The specific supplementation of BbTFO1 reversed these phenotypic changes. As revealed by this work, BbTFO1 can affect the transcription of catalase genes and play vital roles in the maintenance of phenotypes associated with the biological control ability of B. bassiana.


Assuntos
Beauveria/metabolismo , Proteínas Fúngicas/metabolismo , Insetos/microbiologia , Fatores de Transcrição/metabolismo , Virulência/genética , Animais , Beauveria/isolamento & purificação , Beauveria/patogenicidade , Catalase/genética , Catalase/metabolismo , Proteínas Fúngicas/classificação , Proteínas Fúngicas/genética , Regulação Fúngica da Expressão Gênica , Mutação , Estresse Oxidativo/genética , Fenótipo , Filogenia , Estresse Fisiológico , Temperatura , Fatores de Transcrição/classificação , Fatores de Transcrição/genética
6.
J Med Entomol ; 58(4): 1771-1778, 2021 07 16.
Artigo em Inglês | MEDLINE | ID: mdl-33704481

RESUMO

Entomopathogenic fungi such as Beauveria bassiana (Balsamo) Vuillemin and Metarhizium anisopliae/brunneum (Metchnikoff)/Petch have shown promising results for managing the house fly, Musca domestica L. A primary challenge of using these biological control agents (BCAs) in field situations is the time required to induce high adult house fly mortality, typically 6-7 d post-exposure. In this study, virulence of M. anisopliae (strain F52) and four B. bassiana strains were compared. The B. bassiana strains GHA and HF23 are used in commercial products and those were compared with two strains that were isolated from house flies on dairy farms (NFH10 and L90). Assays were conducted by exposing adult house flies to fungal-treated filter paper disks for 2 h. The lethal time to 50% mortality (LT50) at the high concentration of 1 × 109 conidia ranged from 3.8 to 5.2 d for all five strains. GHA, NFH10, and L90 killed flies faster than M. anisopliae strain F52; HF23 did not differ from either the M. anisopliae or the other B. bassiana strains. Attempts with the NFH10 strain to induce faster fly mortality through selection across 10 fungal to fly passages did not result in shorter time to fly death of the selected strain compared with the unselected strain.


Assuntos
Beauveria/patogenicidade , Moscas Domésticas/microbiologia , Metarhizium/patogenicidade , Controle Biológico de Vetores , Seleção Genética , Animais , Beauveria/genética , Feminino
7.
PLoS One ; 16(2): e0240955, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33606688

RESUMO

Entomopathogenic fungi (EPF) are important soil-dwelling entomopathogens, which can be used as biological control agents against pest insects. EPF are capable of causing lethal epizootics in pest insect populations in agroecosystems. During a survey of the orchard soil at an organic farm, different EPF species were collected and identified to species level, using both morphological and molecular techniques. The EPF were trapped from soil samples taken from an apricot orchard. The traps, which were baited in the laboratory, used susceptible host insects, including the last-instar larvae of Galleria mellonella (wax moth larvae) and Tenebrio molitor (mealworm larvae). The potential pathogenicity of the local Metarhizium majus isolate was tested and verified using susceptible laboratory-reared last-instar T. molitor larvae. The identification of the M. majus isolated from South African soil was verified using both morphological and molecular techniques. The occurrence of M. majus in the South African soil environment had not previously been reported.


Assuntos
Metarhizium/genética , Metarhizium/isolamento & purificação , Metarhizium/metabolismo , Animais , Beauveria/isolamento & purificação , Beauveria/patogenicidade , Agentes de Controle Biológico/farmacologia , Insetos/microbiologia , Larva/microbiologia , Controle Biológico de Vetores/métodos , Solo , Microbiologia do Solo , África do Sul
8.
Sci Rep ; 11(1): 3076, 2021 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-33542249

RESUMO

The larval stages of Carmenta theobromae Busck (1910) and Simplicivalva ampliophilobia Davis, Gentili-Poole and Mitter (2008) attack the subcortical zone and pith in guava trees, respectively, in the first productive nucleus of fruit trees in Colombia: Hoya del Río Suárez (HRS). The presence of pest insects has been reported in 98% of the farms sampled in HRS (n = 124), with up to 96 and 11 simultaneous larvae per tree, respectively. Although the aspects of the basic biology and life cycle of both pests have been resolved, there are no strategies for managing populations in the field. Therefore, the aim of this study was to evaluate different management alternatives under laboratory and field conditions in HRS. In laboratory conditions, a completely randomized design was used in two separate experiments, each with six treatments: T1: Spinosad (a mixture of Spinosad A and D); T2: S-1,2-di(ethoxycarbonyl) ethyl 0,0-dimethylphosphorodithioate (chemical control); T3: Lecanicillium lecanii; T4: Beauveria bassiana; T5: Mix of B. bassiana and B. brongniartii, and T6: distilled water (control). The number of dead larvae per replicate per treatment was evaluated (DL), with experimental units of five and three larvae, respectively. In the field, to the two best alternatives found for each pest in the laboratory, pruning and keeping the area around the plants free of weeds were added as cultural management, in two separate additional experiments, each with three larvae as experimental unit per treatment. For C. theobromae, the best laboratory alternatives were chemical control (DL: 3.78) and L. lecanii (DL: 2.33), followed without statistical differences by B. bassiana (DL: 1.67). In the field, the virulence of B. bassiana improved (DL: 3), and together with pruning and keeping the area around the plants clear of weeds (DL: 3), they stood out as the best alternatives. For S. ampliophilobia under laboratory conditions, the best alternatives were Spinosad (2.74) and chemical control (DL: 2.66), without significant difference. In the field, there were no statistical differences between the alternatives, except for the control. This statistical parity of cultural practices, and biological and chemical management is an argument in favor of the use of the former to the detriment of the third, especially when the harmful effects of the molecule S-1,2 di (ethoxycarbonyl) ethyl 0, 0-dimethyl phosphorodithioate have been proven in air, water and agricultural soils, in addition to its association with thyroid cancer in humans. This is a strong argument to favor the use of synergies of cultural and biological management methods framed in IPM, as opposed to the use of chemical agents whose harmful effects are strongly documented, and whose use is becoming increasingly prohibited.


Assuntos
Lepidópteros/microbiologia , Macrolídeos/farmacologia , Controle Biológico de Vetores , Psidium/parasitologia , Animais , Beauveria/patogenicidade , Colômbia , Cordyceps/patogenicidade , Combinação de Medicamentos , Humanos , Hypocreales , Larva/microbiologia , Larva/parasitologia , Lepidópteros/patogenicidade , Metarhizium , Psidium/crescimento & desenvolvimento
9.
Sci Rep ; 11(1): 91, 2021 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-33420123

RESUMO

Beauveria bassiana is a species complex whose isolates show considerable natural genetic variability. However, little is known about how this genetic diversity affects the fungus performance. Herein, we characterized the diversity of genes involved in various mechanisms of the infective cycle of 42 isolates that have different growth rates, thermotolerance and virulence. The analysed genes showed general genetic diversity measured as non-synonymous changes (NSC) and copy number variation (CNV), with most of them being subjected to positive episodic diversifying selection. Correlation analyses between NSC or CNV and the isolate virulence, thermotolerance and growth rate revealed that various genes shaped the biological features of the fungus. Lectin-like, mucin signalling, Biotrophy associated and chitinase genes NSCs correlated with the three biological features of B. bassiana. In addition, other genes (i.e. DNA photolyase and cyclophilin B) that had relatively conserved sequences, had variable CNs across the isolates which were correlated with the variability of either virulence or thermotolerance of B. bassiana isolates. The data obtained is important for a better understanding of population structure, ecological and potential impact when isolates are used as mycoinsecticides and can justify industrialization of new isolates.


Assuntos
Beauveria/genética , Beauveria/patogenicidade , Insetos/microbiologia , Animais , Beauveria/classificação , Beauveria/crescimento & desenvolvimento , Quitinases/genética , Quitinases/metabolismo , Ciclofilinas/genética , Ciclofilinas/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Variação Genética , Filogenia , Virulência
10.
Appl Environ Microbiol ; 87(6)2021 02 26.
Artigo em Inglês | MEDLINE | ID: mdl-33397694

RESUMO

Two FRQ proteins (Frq1 and Frq2) distinct in molecular mass and structure coexist in Beauveria bassiana, an asexual insect-pathogenic fungus. Frq1 and Frq2 have been proven to have opposite nuclear rhythms that can persistently activate developmental activator genes and hence orchestrate nonrhythmic conidiation in vitro under light or in darkness. Here, we report the essentiality of either FRQ, but Frq2 being more important than Frq1, for the fungal virulence and infection cycle. The fungal virulence was attenuated significantly more in the absence of frq2 than in the absence of frq1 through either normal cuticle infection or cuticle-bypassing infection by intrahemocoel injection, accompanied by differentially reduced secretion of Pr1 proteases required for the cuticle infection and delayed development of hyphal bodies in vivo, which usually propagate by yeast-like budding in the host hemocoel to accelerate insect death from mycosis. Despite insignificant changes in radial growth under normal, oxidative, and hyperosmotic culture conditions, conidial yields of the Δfrq1 and Δfrq2 mutants on insect cadavers were sharply reduced, and the reduction increased with shortening daylight length on day 9 or 12 after death, indicating that both Frq1 and Frq2 are required for the fungal infection cycle in host habitats. Intriguingly, the Δfrq1 and Δfrq2 mutants showed hypersensitivity and high resistance to cell wall-perturbing calcofluor white, coinciding respectively with the calcofluor-triggered cells' hypo- and hyperphosphorylated signals of Slt2, a mitogen-activated protein kinase (MAPK) required for mediation of cell wall integrity. This finding offers a novel insight into opposite roles of Frq1 and Frq2 in calcofluor-specific signal transduction via the fungal Slt2 cascade.IMPORTANCE Opposite nuclear rhythms of two distinct FRQ proteins (Frq1 and Frq2) coexisting in an asexual fungal insect pathogen have been shown to orchestrate the fungal nonrhythmic conidiation in vitro in a circadian day independent of photoperiod change. This paper reports essential roles of both Frq1 and Frq2, but a greater role for Frq2, in sustaining the fungal virulence and infection cycle since either frq1 or frq2 deletion led to marked delay of lethal action against a model insect and drastic reduction of conidial yield on insect cadavers. Moreover, the frq1 and frq2 mutants display hypersensitivity and high resistance to cell wall perturbation and have hypo- and hyperphosphorylated MAPK/Slt2 in calcofluor white-triggered cells, respectively. These findings uncover a requirement of Frq1 and Frq2 for the fungal infection cycle in host habitats and provide a novel insight into their opposite roles in calcofluor-specific signal transduction through the MAPK/Slt2 cascade.


Assuntos
Beauveria/metabolismo , Beauveria/patogenicidade , Proteínas Fúngicas/metabolismo , Mariposas/microbiologia , Virulência , Animais , Benzenossulfonatos , Larva/microbiologia , Transdução de Sinais
11.
Environ Microbiol ; 23(2): 1256-1274, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33393158

RESUMO

Laccases are widely present in bacteria, fungi, plants and invertebrates and involved in a variety of physiological functions. Here, we report that Beauveria bassiana, an economic important entomopathogenic fungus, secretes a laccase 2 (BbLac2) during infection that detoxifies insect immune response-generated reactive oxygen species (ROS) and interferes with host immune phenoloxidase (PO) activation. BbLac2 is expressed in fungal cells during proliferation in the insect haemocoel and can be found to distribute on the surface of haemolymph-derived in vivo fungal hyphal bodies or be secreted. Targeted gene-knockout of BbLac2 increased fungal sensitivity to oxidative stress, decreased virulence to insect, and increased host PO activity. Strains overexpressing BbLac2 showed increased virulence, with reduced host PO activity and lowered ROS levels in infected insects. In vitro assays revealed that BbLac2 could eliminate ROS and oxidize PO substrates (phenols), verifying the enzymatic functioning of the protein in detoxification of cytotoxic ROS and interference with the PO cascade. Moreover, BbLac2 acted as a cell surface protein that masked pathogen associated molecular patterns (PAMPs), enabling the pathogen to evade immune recognition. Our data suggest a multifunctional role for fungal pathogen-secreted laccase 2 in evasion of insect immune defenses.


Assuntos
Beauveria/enzimologia , Beauveria/patogenicidade , Insetos/imunologia , Lacase/imunologia , Proteínas de Membrana/imunologia , Animais , Hemolinfa/metabolismo , Hifas/metabolismo , Evasão da Resposta Imune , Insetos/microbiologia , Lacase/metabolismo , Proteínas de Membrana/metabolismo , Monofenol Mono-Oxigenase/imunologia , Espécies Reativas de Oxigênio/imunologia , Virulência
12.
Int J Biol Macromol ; 166: 1162-1172, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33159944

RESUMO

Chitin is one of the major components of the fungal cell wall and contributes to the mechanical strength and shape of the fungal cell. Zn(II)2Cys6 transcription factors are unique to the fungal kingdom and have a variety of functions in some fungi. However, the mechanisms by which Zn(II)2Cys6 proteins affect entomopathogenic fungi are largely unknown. Here, we characterized the Zn(II)2Cys6 transcription factor BbTpc1 in the insect pathogenic fungus Beauveria bassiana. Disruption of BbTpc1 resulted in a distinct changes in vegetative growth and septation patterns, and a significant decrease in conidia and blastospore yield. The ΔBbTpc1 mutant displayed impaired resistance to chemical stresses and heat shock and attenuated virulence in topical and intrahemocoel injection assays. Importantly, the ΔBbTpc1 mutant had an abnormal cell wall with altered wall thickness and chitin synthesis, which were accompanied by transcriptional repression of the chitin synthetase family genes. In addition, comparative transcriptomics revealed that deletion of BbTpc1 altered fungal asexual reproduction via different genetic pathways. These data revealed that BbTpc1 regulates fungal development, chitin synthesis and biological control potential in B. bassiana.


Assuntos
Beauveria/crescimento & desenvolvimento , Beauveria/patogenicidade , Quitina/biossíntese , Proteínas Fúngicas/metabolismo , Insetos/microbiologia , Fatores de Transcrição/metabolismo , Sequência de Aminoácidos , Animais , Autofagia , Beauveria/genética , Parede Celular/metabolismo , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Deleção de Genes , Hifas/crescimento & desenvolvimento , Mutação/genética , Filogenia , Reprodução Assexuada , Esporos Fúngicos/crescimento & desenvolvimento , Estresse Fisiológico , Transcriptoma/genética , Virulência
13.
J Invertebr Pathol ; 178: 107505, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33238166

RESUMO

Mosquitoes transmit many parasites and pathogens to humans that cause significant morbidity and mortality. As such, we are constantly looking for new methods to reduce mosquito populations, including the use of effective biological controls. Entomopathogenic fungi are excellent candidate biocontrol agents to control mosquitoes. Understanding the complex ecological, environmental, and molecular interactions between hosts and pathogens are essential to create novel, effective and safe biocontrol agents. Understanding how mosquitoes recognize and eliminate pathogens such as entomopathogenic fungi may allow us to create insect-order specific biocontrol agents to reduce pest populations. Here we summarize the current knowledge of fungal infection, colonization, development, and replication within mosquitoes and the innate immune responses of the mosquitoes towards the fungal pathogens, emphasizing those features required for an effective mosquito biocontrol agent.


Assuntos
Culicidae/microbiologia , Micoses/imunologia , Controle Biológico de Vetores , Animais , Beauveria/patogenicidade , Fungos/patogenicidade , Imunidade Inata , Controle de Mosquitos
14.
J Biosci ; 452020.
Artigo em Inglês | MEDLINE | ID: mdl-33361627

RESUMO

Tobacco is one of the major industrial crops cultivated worldwide. Chemical control is the main method employed to reduce damage by insect pests. The use of entomopathogenic fungi represents an alternative to replace insecticides. The search for effective strains in the field constitutes a first step when developing a formulation. The objective of this work was to study genetic differences among isolates of entomopathogenic fungi obtained from tobacco grown soils using ISSR markers. The pathogenicity of the strains towards Helicoverpa gelotopoeon and Diabrotica speciosa was also assessed in order to search for a relationship between virulence and genetic diversity. Nineteen isolates were identified according to morphological features and molecular techniques as Beauveria bassiana (11) and Purpureocillium lilacinum (8). The diversity tree generated by ISSR analysis showed a high diversity among the strains. The pathogenicity towards H. gelotopoeon and D. speciosa was assessed and the logistic models generated showed that B. bassiana isolates LPSc1215 and LPSc1364 were the most pathogenic against both insect pests tested. In the diversity tree, these strains were grouped in a same cluster with a similarity level of approximately 85%, indicating a possible relationship between virulence and the band pattern generated.


Assuntos
Fungos/genética , Controle Biológico de Vetores , Microbiologia do Solo , Tabaco/crescimento & desenvolvimento , Animais , Beauveria/genética , Beauveria/patogenicidade , Fungos/crescimento & desenvolvimento , Fungos/patogenicidade , Variação Genética/genética , Hypocreales/genética , Hypocreales/patogenicidade , Insetos/microbiologia , Insetos/parasitologia , Mariposas/microbiologia , Mariposas/parasitologia , Filogenia , Tabaco/microbiologia
15.
Fungal Biol ; 124(12): 1052-1057, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33213785

RESUMO

Autophagy is a conserved intracellular recycling mechanism, in which autophagy-related genes 12 and 16 (ATG12 and ATG16) function in a complex controlling the ubiquitin-like conjugation system. In the insect-pathogenic fungus Beauveria bassiana, ATG12 and ATG16 were functionally characterized. Disruption of BbATG12 or BbATG16 resulted in the absence of autophagic bodies under starvation stress. ΔBbATG12 and ΔBbATG16 mutant strains displayed similar defects in asexual development (conidiation and blastospore formation) and tolerance to oxidative stress. ΔBbATG16 strain exhibited the impaired growth on the media with gelatin or chitin as a single nitrogen source, and ΔBbATG12 displayed decreased growth on the media with sucrose, fructose or maltose as a single carbon source. Both BbATG12 and BbATG16 were required for fungal virulence. BbATG16 mutation had more effects on fungal virulence than BbATG12 in topical infection assay, although both genes had similar contributions to fungal virulence in intrahemocoel injection assay. This study indicates that BbATG12 and BbATG16 mediate diverse biological functions in addition to their convergent roles in autophagy.


Assuntos
Autofagia , Beauveria , Estresse Fisiológico , Virulência , Beauveria/genética , Beauveria/patogenicidade , Proteínas Fúngicas , Esporos Fúngicos
16.
Virulence ; 11(1): 1415-1431, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33103596

RESUMO

ENA1 and ENA2 are P-type IID/ENA Na+/K+-ATPases required for cellular homeostasis in yeasts but remain poorly understood in filamentous fungal insect pathogens. Here, we characterized seven genes encoding five ENA1/2 homologues (ENA1a-c and ENA2a/b) and two P-type IIC/NK Na+/K+-ATPases (NK1/2) in Beauveria bassiana, an insect-pathogenic fungus serving as a main source of fungal insecticides worldwide. Most of these genes were highly responsive to alkaline pH and Na+/K+ cues at transcription level. Cellular Na+, K+ and H+ homeostasis was disturbed only in the absence of ena1a or ena2b. The disturbed homeostasis featured acceleration of vacuolar acidification, elevation of cytosolic Na+/K+ level at pH 5.0 to 9.0, and stabilization of extracellular H+ level to initial pH 7.5 during a 5-day period of submerged incubation. Despite little defect in hyphal growth and asexual development, the Δena1a and Δena2b mutants were less tolerant to metal cations (Na+, K+, Li+, Zn2+, Mn2+ and Fe3+), cell wall perturbation, oxidation, non-cation hyperosmolarity and UVB irradiation, severely compromised in insect pathogenicity via normal cuticle infection, and attenuated in virulence via hemocoel injection. The deletion mutants of five other ENA and NK genes showed little change in vacuolar pH and all examined phenotypes. Therefore, only ENA1a and ENA2b evidently involved in both transmembrane and vacuolar activities are essential for cellular cation homeostasis, insect pathogenicity and multiple stress tolerance in B. bassiana. These findings provide a novel insight into ENA1a- and ENA2b-dependent vacuolar pH stability, cation-homeostatic process and fungal fitness to host insect and environment.


Assuntos
Beauveria/enzimologia , Beauveria/patogenicidade , Homeostase , Mariposas/microbiologia , ATPase Trocadora de Sódio-Potássio/genética , Animais , Beauveria/genética , Proteínas Fúngicas/genética , Hifas/crescimento & desenvolvimento , Larva/microbiologia , Esporos Fúngicos/crescimento & desenvolvimento , Estresse Fisiológico , Vacúolos/química , Virulência
17.
Virulence ; 11(1): 1352-1365, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33017218

RESUMO

Entomopathogenic fungi naturally infect insect hosts in environment. Fungal invasion and host immune defense are still in the progress of co-evolution. In this study, entomopathogenic fungus Beauveria bassiana and lepidopteran insect Galleria mellonella were used to investigate host cellular immunity and fungal strategy to evade host defense. First of all, genome-wide expression revealed the transcriptomic responses of hemocytes to insect mycopathogen, which dynamically varied during infection process. Enrichment analysis indicated that differentially expressed genes were primarily involved in metabolism, cellular process and immune system. Notably, cellular response involved a series of hydrolytic enzyme and antimicrobial peptide genes which were sorted together in clustering analysis. In B. bassiana, a cell-wall protein gene (BbCwp) contributes to fungal development in host hemocoel and virulence. RT-qPCR analyses indicated that infection by ΔBbCwp mutant strain caused the up-regulated expression of a series of immunity-related genes, including ß-1, 3-glucan recognition protein, hydrolytic enzyme and antimicrobial peptide genes. Disruption of BbCwp resulted in a significant change in conidial lectin-binding feature and the enhanced encapsulation by the host hemocytes. After being treated with hydrolytic enzymes, ΔBbCwp mutant displayed a significantly enhanced sensitivity to osmotic and oxidative stresses. In conclusion, fungal invasion initiates comprehensive physiological responses in the host hemocytes. For mycopathogen, cell-wall protein plays an important role in fungal evasion of immunity defense and colonization in host. Our studies provide an initial framework for exploring more mechanistic details about the fungus-host interaction.


Assuntos
Beauveria/genética , Beauveria/patogenicidade , Parede Celular/química , Proteínas Fúngicas/genética , Hemócitos/microbiologia , Mariposas/imunologia , Animais , Beauveria/imunologia , Parede Celular/genética , Proteínas Fúngicas/imunologia , Perfilação da Expressão Gênica , Hemócitos/imunologia , Evasão da Resposta Imune , Mariposas/citologia , Mariposas/microbiologia , Transcriptoma , Virulência
18.
J Invertebr Pathol ; 177: 107477, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33053399

RESUMO

Fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae), is a key invasive pest of maize and other crops in Africa. Entomopathogenic fungi play an important role in regulating the immature stages of this invasive pest as opposed to synthetic pesticides that are hazardous to human, environment and biodiversity. To tackle the adult stage of the pest (the moth) and to improve on the application strategy of the fungal-based biopesticides, this study evaluated the effect of various entomopathogenic fungi isolates on S. frugiperda moths. Twenty-two isolates (16 Metarhizium anisopliae and 6 Beauveria bassiana) were screened in the laboratory to assess their pathogenicity and virulence against S. frugiperda moths. The compatibility of the most pathogenic isolates with S. frugiperda pheromone FALLTRACT lure, the horizontal transmission of the inoculum among S. frugiperda moths, and the effect on oviposition were also determined under laboratory conditions. All 22 fungal isolates screened were pathogenic to the moths, but the mortality varied significantly among the isolates (P < 0.0001) seven days post-treatment. Beauveria bassiana ICIPE 621 and M. anisopliae ICIPE 7 outperformed all the other isolates by causing 100% mortality of the moths with the lowest LT50 values of 3.6 ± 0.1 and 3.9 ± 0.0 days, respectively. Both isolates were also found compatible with FALLTRACT lure, as the lure had no effect on the conidial germination in the laboratory. Male and female moths were able to horizontally transmit conidia of both fungal isolates to untreated moths, causing high mortality of S. frugiperda in 'donor' and 'recipient' groups. In addition, the oviposition, hatchability of eggs and longevity of larvae were significantly affected on the fungal infected females. Although single moths still retained high conidial numbers 72 h post-inoculation, the number of conidia decreased with time. These results suggest that ICIPE 7 and ICIPE 621 could be used in combination with S. frugiperda pheromone in an autodissemination approach to suppress S. frugiperda population.


Assuntos
Beauveria , Agentes de Controle Biológico/farmacologia , Metarhizium , Controle Biológico de Vetores , Spodoptera , Animais , Beauveria/patogenicidade , Beauveria/fisiologia , Feminino , Controle de Insetos , Masculino , Metarhizium/patogenicidade , Metarhizium/fisiologia , Feromônios , Virulência
19.
Fungal Biol ; 124(11): 924-931, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33059844

RESUMO

Small ubiquitin-like modifiers (SUMOs) act as the modifiers that regulate several important eukaryotic cell events during sumoylation, but little is known about the functions of SUMO or sumoylation in filamentous entomopathogens. Here, we report the important roles of a single SUMO-encoding gene, smt3, in Beauveria bassiana, a filamentous fungal insect pathogen that serves as a main source of wide-spectrum fungal insecticides. The deletion of smt3 led to significant growth defects on the minimal media with different carbon and nitrogen sources, an obvious reduction (45.7 %) in aerial conidiation during optimal cultivation, and increasing sensitivities to metal ions, oxidation, cell wall perturbation, and the fungicide carbendazim during conidial germination and/or colony growth. Compared with the wild-type, the percentage of germination of conidia stored at 4 °C decreased by 83.9 %, and virulence to Galleria mellonella via normal infection was delayed by 24.6 %. However, conidial thermotolerance increased slightly by 11.4 % in Δsmt3. These findings concurred with the repressed transcripts of some phenotype-related genes and decreased activities of antioxidant enzymes. Taken together, smt3 or sumoylation plays vital roles in the asexual development, environmental adaptation, and pathogenicity of B. bassiana.


Assuntos
Beauveria , Proteínas Fúngicas , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina , Beauveria/citologia , Beauveria/genética , Beauveria/metabolismo , Beauveria/patogenicidade , Meio Ambiente , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Deleção de Genes , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina/genética , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina/metabolismo , Esporos Fúngicos , Estresse Fisiológico , Virulência/genética
20.
PLoS One ; 15(9): e0238943, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32925935

RESUMO

Inoculating plants with entomopathogenic fungi may influence plant nutrient uptake and growth, and herbivore performance. Knowledge is limited concerning the effects of this symbiosis on higher trophic levels. We examined how fungal treatment of faba bean seeds with the entomopathogenic fungus Beauveria bassiana influenced the choice-behavior and development of the aphid parasitoid Aphidius colemani. We also sampled plant material for analysis of changes in expression of genes related to plant defense pathways. While parasitoids were compatible with plants inoculated with B. bassiana initially (66 vs. 65% parasitization on inoculated and control plants, respectively; similar development times of parasitoids: 9.2 days), the emergence of adult parasitoids originating from aphids on fungus treated plants was significantly lower (67 vs. 76%, respectively). We also found that the defense response changed, similar to induced systemic resistance, when plants were treated with B. bassiana, similarly to what has been found for other plant symbiotic microorganisms. These novel findings show that although the application of entomopathogenic fungi to plants can alter the plants' defense against herbivores, it may also have an impact on beneficial insects, so their function and use should be evaluated on a case-by-case basis.


Assuntos
Beauveria/fisiologia , Controle Biológico de Vetores/métodos , Vicia faba/microbiologia , Beauveria/metabolismo , Beauveria/patogenicidade , Endófitos/fisiologia , Regulação da Expressão Gênica de Plantas/genética , Imunidade Vegetal/imunologia , Sementes/microbiologia , Simbiose , Vicia faba/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...