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1.
J Insect Sci ; 24(4)2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38989843

RESUMO

Cantharidin is a toxic defensive substance secreted by most blister beetles when attacked. It has been used to treat many complex diseases since ancient times and has recently regained popularity as an anticancer agent. However, the detailed mechanism of the cantharidin biosynthesis has not been completely addressed. In this study, we cloned McSTE24 (encoding STE24 endopeptidase) from terpenoid backbone pathway, McCYP305a1 (encoding cytochrome P450, family 305) and McJHEH [encoding subfamily A, polypeptide 1 and juvenile hormone (JH) epoxide hydrolase] associated to JH synthesis/degradation in the blister beetle Mylabris cichorii (Linnaeus, 1758, Coleoptera: Meloidae). Expression pattern analyses across developmental stages in adult males revealed that the expressions of 3 transcripts were closely linked to cantharidin titer exclusively during the peak period of cantharidin synthesis (20-25 days old). In contrast, at other stages, these genes may primarily regulate different biological processes. When RNA interference with double-stranded RNA suppressed the expressions of the 3 genes individually, significant reductions in cantharidin production were observed in males and also in females following McJHEH knockdown, indicating that these 3 genes might primarily contribute to cantharidin biosynthesis in males, but not in females, while females could self-synthesis a small amount of cantharidin. These findings support the previously hypothesized sexual dimorphism in cantharidin biosynthesis during the adult phase. McCYP305a1 collaborates with its upstream gene McSTE24 in cantharidin biosynthesis, while McJHEH independently regulates cantharidin biosynthesis in males.


Assuntos
Cantaridina , Besouros , Proteínas de Insetos , Animais , Cantaridina/metabolismo , Besouros/genética , Besouros/metabolismo , Masculino , Feminino , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Sistema Enzimático do Citocromo P-450/genética , Sistema Enzimático do Citocromo P-450/metabolismo
2.
Curr Genet ; 69(4-6): 253-265, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37726495

RESUMO

Insect pathogenic fungi, also known as entomopathogenic fungi, are one of the largest insect pathogenic microorganism communities, represented by Beauveria spp. and Metarhizium spp. Entomopathogenic fungi have been proved to be a great substitute for chemical pesticide in agriculture. In fact, a lot of functional genes were also already characterized in entomopathogenic fungi, but more depth of exploration is still needed to reveal their complicated pathogenic mechanism to insects. Metarhizium rileyi (Nomuraea rileyi) is a great potential biocontrol fungus that can parasitize more than 40 distinct species (mainly Lepidoptera: Noctuidae) to cause large-scale infectious diseases within insect population. In this study, a comparative analysis of transcriptome profile was performed with topical inoculation and hemolymph injection to character the infectious pattern of M. rileyi. Appressorium and multiple hydrolases are indispensable constituents to break the insect host primary cuticle defense in entomopathogenic fungi. Within our transcriptome data, numerous transcripts related to destruction of insect cuticle rather growth regulations were obtained. Most importantly, some unreported ribosomal protein genes and novel unannotated protein (hypothetical protein) genes were proved to participate in the course of pathogenic regulation. Our current data provide a higher efficiency gene library for virulence factors screen in M. rileyi, and this library may be also useful for furnishing valuable information on entomopathogenic fungal pathogenic mechanisms to host.


Assuntos
Metarhizium , Animais , Metarhizium/genética , Transcriptoma , Insetos/genética , Insetos/microbiologia , Perfilação da Expressão Gênica
3.
Sensors (Basel) ; 22(15)2022 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-35898076

RESUMO

The emergence of underwater acoustic networks has greatly improved the potential capabilities of marine environment detection. In underwater acoustic network applications, node location is a basic and important task, and node location information is the guarantee for the completion of various underwater tasks. Most of the current underwater positioning models do not consider the influence of the uneven underwater medium or the uncertainty of the position of the network beacon modem, which will reduce the accuracy of the positioning results. This paper proposes an underwater acoustic network positioning method based on spatial-temporal self-calibration. This method can automatically calibrate the space position of the beacon modem using only the GPS position and depth sensor information obtained in real-time. Under the asynchronous system, the influence of the inhomogeneity of the underwater medium is analyzed, and the unscented Kalman algorithm is used to estimate the position of underwater mobile nodes. Finally, the effectiveness of this method is verified by simulation and sea trials.


Assuntos
Redes de Comunicação de Computadores , Transdutores , Acústica , Calibragem , Desenho de Equipamento , Análise de Falha de Equipamento
4.
Fungal Genet Biol ; 155: 103612, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34303798

RESUMO

Metarhizium rileyi, a well-known filamentous biocontrol fungus, is the main pathogen of numerous field pests, especially noctuid pests. To explore the potential factors involved in the fungal pathogenicity, MrSte12, an important and conserved functional transcription factor in mitogen-activated protein kinase pathway was carried out by functional analysis. Homologous recombination was used to disrupt the MrSte12 gene in M. rileyi. The deletant fungal strain exhibited malformed hyphae and impaired conidiogenesis, and conidia could not be collected from △MrSte12 in vitro towards SMAY medium. Although conidia could be collected again supplemented with KCl within SMAY medium, the conidial germination, growth and stress tolerance were much weaker compared with that in WT. Additionally, △MrSte12 showed a dramatic reduction in virulence in intra-hemolymph injections and no pathogenicity in topical inoculations against noctuid pests, which is due to the failure of appressorium formation. Moreover, the content of chitin and ß-1, 3-glucan in cell wall significantly reduced in mutant conidia. These results indicate that the MrSte12 gene markedly contributes to invasive growth and conidiation, as well as the major pathogenicity in M. rileyi.


Assuntos
Metarhizium , Fatores de Transcrição , Animais , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Regulação Fúngica da Expressão Gênica , Metarhizium/genética , Metarhizium/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Virulência/genética
5.
Fungal Biol ; 125(8): 596-608, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34281653

RESUMO

Fungal dimorphism is the ability of certain fungi to switch between two different cellular forms, yeast and mycelial forms, in response to external environmental factors. The pacC/Pal signal transduction pathway responds to neutral and alkaline environments and is also involved in the fungal dimorphic transition. In this study, we investigated the function of the pacC homolog, MripacC, which regulates the dimorphic transition and modulates virulence of the insect pathogenic fungus Metarhizium rileyi. MripacC expression was upregulated under alkaline condition, with increased number of yeast-like cells compared to the number of hyphae cells. A MripacC deletion mutant (ΔMripacC) was obtained by homologous replacement and exhibited decreased blastospore budding, with direct development of conidia into hyphae without entering the yeast-like stage when cultured on alkaline medium. Observation of host hemolymph morphology and analysis of samples to detect the main immune factors revealed a decreased ability of ΔMripacC to evade the host immune system. The results of insect bioassays showed that ΔMripacC had decreased virulence with extended median lethality time. Together, the results suggested that MripacC not only regulated adaptation to acidic and alkaline environments, but also influenced virulence by budding blastospores. This elucidation of the function of MripacC adds to our understanding of blastospore budding and virulence of this fungal pathogen.


Assuntos
Metarhizium , Virulência , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Regulação Fúngica da Expressão Gênica , Hifas/genética , Hifas/metabolismo , Metarhizium/genética , Metarhizium/crescimento & desenvolvimento , Metarhizium/metabolismo , Deleção de Sequência , Esporos Fúngicos/genética , Esporos Fúngicos/metabolismo , Virulência/genética
6.
Fungal Genet Biol ; 150: 103508, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33675988

RESUMO

The pathogenicity of Metarhizium rileyi is a multi-faceted process that depends on many factors. This study attempts to decipher those factors of M. rileyi by investigating its pathogenicity against Spodoptera litura (Lepidoptera: Noctuidae) larvae. Through morphogenesis analysis, we for the first time demonstrated the infection structure, appressorium, of M. rileyi that can generate a more than 4 MPa turgor pressure. The Mrpmk1 gene was found to be essential for appressorium differentiation and mycelium reemerging, ΔMrpmk1 mutant exhibited no pathogenicity towards S. litura by natural infection process. Delayed appressorium formation time, decreased appressorium formation rate and turgor pressure of ΔMrpbs2 mutant manifested itself in postponed death time and lower mortality against S. litura. Following invasion into the larval hemocoel, M. rileyi cells transformed into blastospores, which may be conducive to dispersal and propagation, moreover, the blastospore form M. rileyi may subverted phagocytic defenses. Then M. rileyi cells morphed into extended hyphal body to cope with elongated hemocytes that participated in encapsulation. In the end, M. rileyi mycelia reemerged from the larval cadaver evenly to form muscardine cadaver. Eventually, conidia were produced to complete the infection cycle. During the infection, M. rileyi triggered both cellular and humoral immunity of S. litura. Besides morphological changes, stage-specifically produced oxalic acid and F-actin arrangement may play roles in nutrient acquisition and mycelium reemerging, respectively.


Assuntos
Proliferação de Células , Hemolinfa/microbiologia , Larva/imunologia , Larva/fisiologia , Metarhizium/patogenicidade , Micélio/crescimento & desenvolvimento , Spodoptera/fisiologia , Animais , Imunidade Celular , Imunidade Humoral , Metarhizium/genética , Metarhizium/crescimento & desenvolvimento , Spodoptera/imunologia , Virulência
7.
Mol Med Rep ; 22(3): 1747-1758, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32582970

RESUMO

Ovarian cancer is the most frequent cause of death among gynecological cancers. In the present study, the anti­cancer effect of liriopesides B, a steroidal saponin from Liriope spicata var. prolifera, against A2780 cells was investigated. Transwell chambers were adopted to assess its effect on cell invasion and chemotaxis abilities. Flow cytometry was used to analyze the cell cycle and apoptosis. Reverse transcription­quantitative PCR was employed to examine gene expression levels. Western blot analysis was performed to detect protein expression levels. Liriopesides B inhibited the invasion and chemotactic movement ability of A2780 cells in a dose­dependent manner. Furthermore, liriopesides B caused cell cycle arrest in A2780 cells at the G1 phase following incubation for 24, 48 and 72 h. Hoechst 33258 staining indicated that, following incubation for 48 h, liriopesides B induced cell apoptosis in a dose­dependent manner. Flow cytometry verified that liriopesides B induced apoptosis in A2780 cells and induced late apoptosis in a dose­dependent manner. Furthermore, liriopesides B significantly increased the mRNA expression levels of E­CADHERIN, p21 and p27 and decreased the gene expression levels of BCL­2, which was consistent with its protein expression levels. In conclusion, liriopesides B possess anti­cancer properties, including inhibition of metastasis­associated behaviors, cell cycle arrest and induction of apoptosis. Therefore, liriopesides B may be considered as a candidate drug against ovarian cancer.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Compostos Heterocíclicos de 4 ou mais Anéis/farmacologia , Neoplasias Ovarianas/genética , Compostos de Espiro/farmacologia , Antígenos CD/genética , Antígenos CD/metabolismo , Caderinas/genética , Caderinas/metabolismo , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Inibidor de Quinase Dependente de Ciclina p21/genética , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Inibidor de Quinase Dependente de Ciclina p27/genética , Inibidor de Quinase Dependente de Ciclina p27/metabolismo , Relação Dose-Resposta a Droga , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo
8.
Microb Biotechnol ; 13(5): 1489-1501, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32395911

RESUMO

The GATA-type sexual development transcription factor NsdD has been implicated in virulence, secondary metabolism and asexual development in filamentous fungi. However, little is known about its function in the yeast-to-hypha transition and in microsclerotium formation. In the current study, the orthologous NsdD gene MrNsdD in the entomopathogenic fungus Metarhizium rileyi was characterized. Transcriptional analysis indicated that MrNsdD was involved in yeast-to-hypha transition, conidiation and microsclerotium formation. After targeted deletion of MrNsdD, dimorphic transition, conidiation, fungal virulence and microsclerotium formation were all impaired. Compared with the wild-type strain, the ΔMrNsdD mutants were hypersensitive to thermal stress. Furthermore, transcriptome sequencing analysis revealed that MrNsdD regulated a distinct signalling pathway in M. rileyi during the yeast-to-hypha transition or microsclerotium formation, but exhibited overlapping regulation of genes during the two distinct developmental stages. Taken together, characterization of the MrNsdD targets in this study will aid in the dissection of the molecular mechanisms of dimorphic transition and microsclerotium development.


Assuntos
Metarhizium , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Fatores de Transcrição GATA , Regulação Fúngica da Expressão Gênica , Metarhizium/genética , Metarhizium/metabolismo , Esporos Fúngicos/metabolismo , Virulência
9.
Appl Environ Microbiol ; 86(8)2020 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-32005738

RESUMO

APSES-type transcription factors (TFs) have analogous and diverse functions in the regulation of fungal morphogenesis processes. However, little is known about these functions in microsclerotium formation. In this study, we characterized two orthologous APSES genes (MrStuA and MrXbp) in the entomopathogenic fungus Metarhizium rileyi Deletion of either MrStuA or MrXbp impaired dimorphic transition, conidiation, fungal virulence, and microsclerotium formation. Compared with the wild-type strain, ΔMrStuA and ΔMrXbp mutants were hypersensitive to thermal and oxidative stress. Furthermore, transcriptome sequencing analysis revealed that MrStuA and MrXbp independently regulate their own distinctive subsets of signaling pathways during dimorphic transition and microsclerotium formation, but they also show an overlapping regulation of genes during these two distinct morphogenesis processes. These results provide a global insight into vital roles of MrStuA and MrXbp in M. rileyi and aid in dissection of the interacting regulatory mechanisms of dimorphism transition and microsclerotium development.IMPORTANCE Transcription factors (TFs) are core components of the signaling pathway and play an important role in transcriptional regulation of gene expression during fungal morphogenesis processes. A prevailing theory suggests an interplay between different TFs regulating microsclerotial differentiation; however, the persisting issue remains that these interplay mechanisms are not clear. Here, we analyzed two members of the APSES-type TFs in Metarhizium rileyi using a gene deletion strategy and transcriptome analysis. Mutants were significantly impaired in microsclerotium formation and dimorphic transition. Transcriptome analysis provided evidence for interacting regulatory mechanisms by the two TFs in microsclerotium formation and dimorphic transition. Furthermore, we investigated their overlapping roles in mediating the expression of genes required for different fungal morphogenesis processes. Characterization of TFs in this study will aid in dissecting the interplay between regulatory mechanisms in fungal morphogenesis processes.


Assuntos
Proteínas Fúngicas/genética , Metarhizium/genética , Fatores de Transcrição/genética , Proteínas Fúngicas/metabolismo , Metarhizium/crescimento & desenvolvimento , Morfogênese/genética , Fatores de Transcrição/metabolismo
10.
World J Microbiol Biotechnol ; 35(3): 46, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30825005

RESUMO

Microsclerotia (MS) produced in the liquid culture of the dimorphic insect pathogen Metarhizium rileyi can be used as a mycoinsecticide. Bioinformatics analysis demonstrated that the cell cycle signaling pathway was involved in regulating MS formation. To investigate the mechanisms by which the signaling pathway is regulated, a cell cycle box binding transcription factor MrSwi6 of M. rileyi was characterized. MrSwi6 was highly expressed during periods of yeast-hypha transition and conidia and MS formation. When compared with wild-type and complemented strains, disruption of MrSwi6 significantly reduced conidia (15-36%) and MS formation (96.2%), and exhibited decreased virulence levels. Digital expression profiling revealed that genes involved in antioxidation, pigment biosynthesis, and ion transport and storage were regulated by MrSwi6 during conidia and MS development. These results confirmed the significance of MrSwi6 in dimorphic transition, conidia and MS formation, and virulence in M. rileyi.


Assuntos
Genes Fúngicos/genética , Metarhizium/crescimento & desenvolvimento , Metarhizium/genética , Caracteres Sexuais , Fatores de Transcrição/genética , Animais , Antioxidantes/metabolismo , Sequência de Bases , Ciclo Celular , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Perfilação da Expressão Gênica , Regulação Fúngica da Expressão Gênica , Hifas/crescimento & desenvolvimento , Insetos/microbiologia , Transporte de Íons , Metarhizium/citologia , Metarhizium/patogenicidade , Mutação , Pigmentação , Transdução de Sinais , Esporos Fúngicos/crescimento & desenvolvimento , Virulência/genética
11.
Exp Ther Med ; 17(3): 1870-1876, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30783462

RESUMO

The aim of the present study was to investigate the efficiency of the gyrB gene derived from Burkholderia gladioli pv.Alliicola (Bga) on the identification of Bga from the B. cepacia complex (Bcc) based on the COnsensus-DEgenerate Hybrid Oligonucleotide Primer (CODEHOP) strategy. A set of primers used for the specific amplification of the gyrB gene in Bga were designed according to the CODEHOP principle. A total of 1,644 bp of the gyrB gene sequence of Bga were acquired by CODEHOP amplification. The sequence was blasted in GenBank and it revealed an average of 86% similarity with the gyrB gene of nine genomovars of Bcc. A phylogenetic tree was constructed using the gyrB gene sequences. The microarray method was adopted to discriminate Bga from Bcc based on the specific probes designed upon the gyrB gene, and five genomovars of Bcc demonstrated a good discrimination from Bga on the microarray chip. CODEHOP strategy succeeded in amplification of the gyrB gene of Bga, which made it possible for the identification of Bga from five genomovars of Bcc.

12.
Microb Biotechnol ; 11(6): 1157-1169, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30160031

RESUMO

Microsclerotia (MS) are pseudoparenchymatous aggregations of hyphae of fungi that can be induced in liquid culture for biocontrol applications. Previously, we determined that the high-osmolarity glycerol (HOG) signalling pathway was involved in regulating MS development in the dimorphic insect pathogen Metarhizium rileyi. To further investigate the mechanisms by which the signalling pathway is regulated, we characterized the transcriptional factor MrMsn2, a homologue of the yeast C2 H2 transcriptional factor Msn2, which is predicted to function downstream of the HOG pathway in M. rileyi. Compared with wild-type and complemented strains, disruption of MrMsn2 increased the yeast-to-hypha transition rate, enhanced conidiation capacity and aggravated pigmentation in M. rileyi. The ▵MrMsn2 mutants were sensitive to stress, produced morphologically abnormal clones and had significantly reduced MS formation and decreased virulence levels. Digital expression profiling revealed that genes involved in antioxidation, pigment biosynthesis and ion transport and storage were regulated by MrMsn2 during conidia and MS development. Taken together, our findings confirm that MrMsn2 controlled the yeast-to-hypha transition, conidia and MS formation, and virulence.


Assuntos
Proteínas Fúngicas/metabolismo , Hifas/crescimento & desenvolvimento , Metarhizium/metabolismo , Esporos Fúngicos/crescimento & desenvolvimento , Fatores de Transcrição/metabolismo , Cor , Proteínas Fúngicas/genética , Regulação Fúngica da Expressão Gênica , Hifas/genética , Hifas/metabolismo , Metarhizium/genética , Metarhizium/crescimento & desenvolvimento , Pigmentos Biológicos/metabolismo , Esporos Fúngicos/genética , Esporos Fúngicos/metabolismo , Fatores de Transcrição/genética
13.
World J Microbiol Biotechnol ; 34(8): 107, 2018 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-29971586

RESUMO

The high osmolarity glycerol (HOG) pathway plays important role in Metarhizium rileyi microsclerotia (MS) development. To investigate how M. rileyi transduce growth stress and regulate MS development via mitogen-activated protein kinase kinase (MAPKK) Pbs2, phenotypic characterization of the yeast Pbs2 homolog were performed. Expression of pbs2 peaked when MS formation occurred day 3 in liquid amended medium. Compared with wild-type and complemented strains, deletion mutant of pbs2 (Δpbs2) delayed dimorphic switch and vegetative growth, displayed sensitivities to various stress, and significantly reduced conidial (98%) and MS (40%) yields. Furthermore, transcription analysis showed that other genes of HOG signaling pathway were down-regulated in Δpbs2 mutants. Insect bioassays revealed that Δpbs2 mutants had decreased virulence levels in topical (24%) and injection (53%) bioassays. This study confirmed that Pbs2 play important roles in colony morphology, conidiation, stresses response and MS development in M. rileyi.


Assuntos
Metarhizium/metabolismo , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Esporos Fúngicos/metabolismo , Estresse Psicológico , Animais , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Amplificação de Genes , Deleção de Genes , Perfilação da Expressão Gênica , Regulação Fúngica da Expressão Gênica , Técnicas de Inativação de Genes , Genes Fúngicos/genética , Glicerol , Metarhizium/genética , Metarhizium/patogenicidade , Quinases de Proteína Quinase Ativadas por Mitógeno/genética , Concentração Osmolar , Proteínas de Saccharomyces cerevisiae/metabolismo , Transdução de Sinais , Spodoptera , Esporos Fúngicos/genética , Esporos Fúngicos/crescimento & desenvolvimento , Virulência
14.
Appl Microbiol Biotechnol ; 102(10): 4577-4588, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29589093

RESUMO

Internal oxidative stress can trigger microsclerotia (MS) formation of Metarhizium rileyi in liquid culture. Activator protein 1 (AP1) is a transcription factor and an important determinant of the response to oxidative stress. To investigate how M. rileyi responds to internal oxidative stress and how MS development is regulated, the Mrap1 gene was characterized. Mrap1 was highly expressed during periods of invasive hyphal growth and in response to changing culture conditions during MS development. Compared with the wild-type and complemented strains, ΔMrap1 mutants exhibited various defects in aerial hyphal growth, yeast-to-hypha transition, and conidia and MS formation. ΔMrap1 mutants also displayed sensitivity to oxidative stress, were morphologically abnormal, and responded differently to oxidative stress during MS development. ΔMrap1 mutants had significantly reduced conidial (74-82%) and MS (99%) yields. Insect bioassays revealed that ΔMrap1 mutants displayed reduced virulence in topical (43-76%) and injection (45-70%) bioassays. Moreover, the ability of ΔMrap1 mutants to grow out of the cuticle was reduced due to impaired conidiation on the host cadaver. Digital gene expression profiling revealed that genes involved in antioxidation, pigment biosynthesis, and ion transport were regulated by Mrap1 during MS development. Taken together, our results confirm the importance of Mrap1 in vegetative growth, conidia and MS formation, and virulence.


Assuntos
Proteínas Fúngicas/metabolismo , Regulação Fúngica da Expressão Gênica , Metarhizium/citologia , Metarhizium/genética , Estresse Oxidativo/genética , Fator de Transcrição AP-1/genética , Fator de Transcrição AP-1/metabolismo , Perfilação da Expressão Gênica , Esporos Fúngicos/genética , Virulência/genética
15.
World J Microbiol Biotechnol ; 34(2): 26, 2018 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-29340841

RESUMO

Targeted gene disruption via Agrobacterium tumefaciens-mediated transformation (ATMT) and homologous recombination is the most common method used to identify and investigate the functions of genes in fungi. However, the gene disruption efficiency of this method is low due to ectopic integration. In this study, a high-efficiency gene disruption strategy based on ATMT and the split-marker method was developed for use in Nomuraea rileyi. The ß-glucuronidase (gus) gene was used as a negative selection marker to facilitate the screening of putative transformants. We assessed the efficacy of this gene disruption method using the NrCat1, NrCat4, and NrPex16 genes and found that the targeting efficiency was between 36.2 and 60.7%, whereas the targeting efficiency using linear cassettes was only 1.0-4.2%. The efficiency of negative selection assays was between 64.1 and 82.3%. Randomly selected deletion mutants exhibited a single copy of the hph cassette. Therefore, high-throughput gene disruption could be possible using the split-marker method and the majority of ectopic integration transformants can be eliminated using negative selection markers. This study provides a platform to study the function of genes in N. rileyi.


Assuntos
Agrobacterium tumefaciens/genética , Biomarcadores , Genes Bacterianos/genética , Genes Fúngicos/genética , Metarhizium/genética , Transformação Genética/genética , DNA Bacteriano/genética , Proteínas Fúngicas/genética , Engenharia Genética , Vetores Genéticos/genética , Glucuronidase/genética , Proteínas de Membrana/genética , Mutagênese Insercional , Proteínas Serina-Treonina Quinases/genética , Deleção de Sequência
16.
Biotechnol Appl Biochem ; 64(5): 667-676, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26988567

RESUMO

Cantharidin, a defensive terpene compound synthesized by the meloid beetle (Coleoptera, Meloidae), is an important anticancer agent. However, there has been little study done on how this compound synthesized by the beetle. In this paper, a farnesyl pyrophosphate synthase (FPPS) gene, designated McFPPS, was isolated from Mylabris cichorii by reverse transcription PCR based on conserved domains in other organisms. Multiple alignment analysis showed that the deduced amino acids shared >70% homology with FPPSs from other species and contained typically seven conservative regions. Gene expression profile analysis revealed that McFPPS was expressed throughout the tested growth stages of M. cichorii adults, whereas the transcripts accumulated to the highest level at 20 days in male adults while the highest expression level appeared at 15 days in females. Tissue expression pattern analysis showed that McFPPS was expressed constitutively in all tested tissues and a relatively higher expression level in the alimentary canal of males, but no significant tissue difference in the females. For the first time, a RNA interference strategy was employed to induce a greater suppression of McFPPS mRNA, and thus a sharp decrease in the expression levels of downstream genes and the concentration of product. All these results indicated that McFPPS may be directly involved or play an essential role in the biosynthesis of cantharidin.


Assuntos
Besouros , Geraniltranstransferase/genética , Proteínas de Insetos/genética , Animais , Cantaridina/análise , Cantaridina/metabolismo , Clonagem Molecular , Besouros/enzimologia , Besouros/genética , Besouros/fisiologia , Feminino , Geraniltranstransferase/metabolismo , Geraniltranstransferase/farmacologia , Proteínas de Insetos/metabolismo , Proteínas de Insetos/farmacologia , Larva/efeitos dos fármacos , Masculino , Especificidade de Órgãos , Interferência de RNA
17.
Sci Rep ; 6: 38765, 2016 12 12.
Artigo em Inglês | MEDLINE | ID: mdl-27941838

RESUMO

Microsclerotia (MS) formation was successfully induced in Metarhizium rileyi under changing liquid culture conditions. Mitogen-activated protein kinases (MAPKs) play important roles in fungal development and in coordinating many stress responses. To investigate how M. rileyi transduces growth stress and regulates MS differentiation, we characterized the roles of two MAPKs, Hog1- and Slt2-type orthologues, in M. rileyi. Compared with the wild-type strain, the deletion mutants of Mrhog1 (ΔMrhog1) and Mrslt2 (ΔMrslt2) delayed germination and vegetative growth, displayed sensitivities to various stress, and produced morphologically abnormal clones. The ΔMrhog1 and ΔMrslt2 mutants significantly reduced conidial (42-99%) and MS (96-99%) yields. A transcriptional analysis showed that the two MAPKs regulate MS development in a cooperative manner. Insect bioassays revealed that ΔMrhog1 and ΔMrslt2 had decreased virulence levels in topical (36-56%) and injection (78-93%) bioassays. Our results confirmed the roles of MrHog1 and MrSlt2 in sensing growth-related stress and in regulating MS differentiation.


Assuntos
MAP Quinases Reguladas por Sinal Extracelular , Proteínas Fúngicas , Deleção de Genes , Metarhizium , Controle Biológico de Vetores , Spodoptera/microbiologia , Animais , MAP Quinases Reguladas por Sinal Extracelular/genética , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Metarhizium/genética , Metarhizium/metabolismo , Metarhizium/patogenicidade
18.
PLoS One ; 11(7): e0159004, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27427975

RESUMO

Droplet digital polymerase chain reaction (ddPCR) is a novel molecular biology technique providing absolute quantification of target nucleic acids without the need for an external calibrator. Despite its emerging applications in medical diagnosis, there are few reports of its use for the detection of plant pathogens. This work was designed to assess the diagnosis potential of the ddPCR for absolute quantitative detection of Xanthomonas citri subsp. citri, a quarantine plant pathogenic bacterium that causes citrus bacterial canker in susceptible Citrus species. We transferred an established quantitative PCR (qPCR) assay for citrus bacterial canker diagnosis directly to the ddPCR format and compared the performance of the two methods. The qPCR assay has a broader dynamic range compared to the ddPCR assay and the ddPCR assay has a significantly higher degree of sensitivity compared to the qPCR assay. The influence of PCR inhibitors can be reduced considerably in the ddPCR assay because the collection of end-point fluorescent signals and the counting of binomial events (positive or negative droplets) are associated with a Poisson algorithm. The ddPCR assay also shows lower coefficient of variation compared to the qPCR assay especially in low target concentration. The linear association of the measurements by ddPCR and qPCR assays is strong (Pearson correlation = 0.8633; P<0.001). Receiver operating characteristic analysis indicates the ddPCR methodology is a more robust approach for diagnosis of citrus bacterial canker. In summary, the results demonstrated that the ddPCR assay has the potential for the quantitative detection of X. citri subsp. citri with high precision and accuracy as compared with the results from qPCR assay. Further studies are required to evaluate and validate the value of ddPCR technology in the diagnosis of plant disease and quarantine applications.


Assuntos
Citrus/microbiologia , Doenças das Plantas/microbiologia , Reação em Cadeia da Polimerase/métodos , Xanthomonas/genética , Xanthomonas/isolamento & purificação , Algoritmos , DNA Bacteriano/análise , DNA Bacteriano/genética , Curva ROC
19.
Front Microbiol ; 7: 931, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27379061

RESUMO

Iron is an indispensable factor for the dimorphic insect pathogenic Nomuraea rileyi to form persistent microsclerotia which can replace conidia or blastospores for commercial mass production. There are two high affinity iron acquisition pathways in N. rileyi, siderophore-assisted iron mobilization and reductive iron assimilation systems. Transcription of the two iron uptake pathways related genes is induced under iron-limiting conditions. Stage-specific iron uptake-related genes expression during microsclerotia development shows siderophore-mediated iron acquisition genes are rigorously upregulated specifically during the formation and mature period while reductive iron assimilation related genes just display a higher expression at the late maturation period. Abrogation of reductive iron assimilation, by the deletion of the high affinity iron permease (NrFtrA), has no visible effect on microsclerotia biogenesis in N. rileyi. In sharp contrast, N. rileyi L-ornithine-N(5)-monooxygenase (NrSidA), required for synthesis of all siderophores, is absolutely necessary for the development of pigmented microsclerotia. In agreement with the lower intracellular iron contents of microsclerotia in ΔNrSidA strains, not only the pigments, but both the number and the biomass are also noticeably reduced. Certain concentration of ROS is required for promoting microsclerotia biogenesis. Combined with expression pattern analysis of related genes and quantitative of intracellular iron or extracellular siderophore in WT and mutants, these data demonstrate the lack of adequate intracellular iron caused by the loss of the siderophore results in the deficiency of ROS detoxication. Furthermore, ΔNrSidA strains show significantly increased sensitivity to hydrogen peroxide. Besides, NrSidA, but not NrFtrA, play a crucial role in vegetative growth under iron-limiting conditions, conidiation, and dimorphic switching. Remarkably, the slower growth of the ΔNrSidA strains in vivo due to a reduced capacity for iron acquisition leads to the loss of virulence in Spodoptera litura while the ΔNrFtrA mutants behaved as WT during infection. Together, these results prove siderophore-assisted iron mobilization is the major pathway of cellular iron uptake and essential for conidiation, dimorphism transition, oxidative stress resistance, pigmented microsclerotium formation and full virulence.

20.
PLoS One ; 11(1): e0146953, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26752526

RESUMO

The dried body of Mylabris cichorii is well-known Chinese traditional medicine. The sesquiterpenoid cantharidin, which is secreted mostly by adult male beetles, has recently been used as an anti-cancer drug. However, little is known about the mechanisms of cantharidin biosynthesis. Furthermore, there is currently no genomic or transcriptomic information for M. cichorii. In this study, we performed de novo assembly transcriptome of M. cichorii using the Illumina Hiseq2000. A single run produced 9.19 Gb of clean nucleotides comprising 29,247 sequences, including 23,739 annotated sequences (about 81%). We also constructed two expression profile libraries (20-25 day-old adult males and 20-25 day-old adult females) and discovered 2,465 significantly differentially-expressed genes. Putative genes and pathways involved in the biosynthesis of cantharidin were then characterized. We also found that cantharidin biosynthesis in M. cichorii might only occur via the mevalonate (MVA) pathway, not via the methylerythritol 4-phosphate/deoxyxylulose 5-phosphate (MEP/DOXP) pathway or a mixture of these. Besides, we considered that cantharidin biosynthesis might be related to the juvenile hormone (JH) biosynthesis or degradation. The results of transcriptome and expression profiling analysis provide a comprehensive sequence resource for M. cichorii that could facilitate the in-depth study of candidate genes and pathways involved in cantharidin biosynthesis, and may thus help to improve our understanding of the mechanisms of cantharidin biosynthesis in blister beetles.


Assuntos
Cantaridina/química , Besouros/metabolismo , Transcriptoma , Animais , DNA Complementar/metabolismo , Eritritol/análogos & derivados , Eritritol/química , Feminino , Perfilação da Expressão Gênica , Biblioteca Gênica , Genoma de Inseto , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Hormônios Juvenis/química , Masculino , Medicina Tradicional Chinesa , Ácido Mevalônico/química , Análise de Sequência de DNA , Xilose/análogos & derivados , Xilose/química
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