RESUMO
Paeciliomyces variotii is a thermo-tolerant, ubiquitous fungus commonly found in food products, indoor environments, soil and clinical samples. It is a well-known biocontrol agent used against phytopathogenic fungi and its metabolites have many industrial applications. Rare reports of P. variotii-related human infections have been found in the medical literature. In this study, we report for the first time the infection of P. variotii isolated from a soil sample collected in a rice field with a double-stranded RNA virus, Paeciliomyces variotii partitivirus 1 (PvPV-1) in the family Partitiviridae. P. variotii harboured icosahedral virus particles 30 nm in diameter with two dsRNA segments 1758 and 1356 bp long. Both dsRNA1 and dsRNA2 have a single open reading frame encoding proteins of 63 and 40 kDa, respectively. These proteins have significant similarity to the RNA-dependent RNA polymerase and capsid protein encoded by the genomic segments of several viruses from the family Partitiviridae. Phylogenetic analysis revealed that PvPV-1 belongs to the family Partitiviridae but in an unclassified group/genus, tentatively nominated Zetapartitivirus. PvPV-1 was found to increase the growth rate of the host fungus, as indicated by time course experiments performed on a range of different media for virus-infected and virus-free isogenic lines. Further, dual-culture assays performed for both isogenic lines confirmed the antagonistic potential of P. variotii against other phytopathogenic fungi. The findings of this study assist us in understanding P. variotii as a potential biocontrol agent, together with plant-fungus-virus interactions.
Assuntos
Byssochlamys , Proteínas do Capsídeo , Humanos , Filogenia , SoloRESUMO
White areas of star-type bicolour petals of petunia (Petunia hybrida) are caused by post-transcriptional gene silencing (PTGS) of the key enzyme of anthocyanin biosynthesis. We observed blotched flowers and a vein-clearing symptom in aged petunia plants. To determine the cause of blotched flowers, we focused on an endogenous pararetrovirus, petunia vein clearing virus (PVCV), because this virus may have a suppressor of PTGS (VSR). Transcripts and episomal DNAs derived from proviral PVCVs accumulated in aged plants, indicating that PVCV was activated as the host plant aged. Furthermore, DNA methylation of CG and CHG sites in the promoter region of proviral PVCV decreased in aged plants, suggesting that poor maintenance of DNA methylation activates PVCV. In parallel, de novo DNA methylation of CHH sites in its promoter region was also detected. Therefore, both activation and inactivation of PVCV occurred in aged plants. The accumulation of PVCV transcripts and episomal DNAs in blotched regions and the detection of VSR activity support a mechanism in which suppression of PTGS by PVCV causes blotched flowers.
Assuntos
Caulimoviridae/metabolismo , Flores/virologia , Petunia/virologia , Caulimoviridae/genética , Cor , Metilação de DNA , DNA Viral/genética , Flores/anatomia & histologia , Regulação da Expressão Gênica de Plantas , Petunia/anatomia & histologia , Provírus/genética , Interferência de RNA , Reação em Cadeia da Polimerase em Tempo RealRESUMO
A double-stranded RNA (dsRNA) of approximately 16 kbp was isolated from symptomless common buckwheat (Fagopyrum esculentum) plants. The size of the dsRNA suggested that it was the replicative form of an endornavirus. The dsRNA was sequenced, and it consisted of 15,677 nt, containing a single open reading frame that potentially encoded a polyprotein of 5190 aa. The polyprotein contained conserved domains for a viral methyltransferase, viral RNA helicase 1, MSCRAMM family adhesion SdrC, UDP-glycosyltransferase, and viral RNA-dependent RNA polymerase 2. A site-specific nick in the plus strand was detected near the 5' end of the dsRNA. BLASTp analysis showed that the polyprotein shared the highest identity with the polyprotein of winged bean endornavirus 1. Results of phylogenetic analysis supported placing this novel virus from common buckwheat, which was provisionally named "Fagopyrum esculentum endornavirus 1", in the genus Alphaendornavirus of the family Endornaviridae.
Assuntos
Fagopyrum , Vírus de RNA , Sequência de Bases , Fagopyrum/genética , Genoma Viral , Fases de Leitura Aberta , Filogenia , Doenças das Plantas , Vírus de RNA/genética , RNA de Cadeia Dupla/genética , Análise de Sequência de DNA , Proteínas Virais/genéticaRESUMO
Members of the family Chrysoviridae are isometric, non-enveloped viruses with segmented, linear, dsRNA genomes. There are 3-7 genomic segments, each of which is individually encapsidated. Chrysoviruses infect fungi, plants and possibly insects, and may cause hypovirulence in their fungal hosts. Chrysoviruses have no known vectors and lack an extracellular phase to their replication cycle; they are transmitted via intracellular routes within an individual during hyphal growth, in asexual or sexual spores, or between individuals via hyphal anastomosis. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the taxonomy of the family Chrysoviridae, which is available at ictv.global/report/chrysoviridae.
Assuntos
Vírus de RNA/classificação , Animais , Classificação , Fungos/patogenicidade , Fungos/virologia , Genoma Viral , Insetos/virologia , Plantas/virologiaRESUMO
RNA silencing is a fundamental mechanism to maintain plant growth and development, and regulation of the size distribution of small interfering RNAs (siRNAs) is critical in the control of normal gene expression throughout a plant's life cycle. However, the cause of organ- and developmental stage-specific accumulation of siRNAs has never been reported. Whereas 24 nt siRNAs accumulated about 5.3-fold more than 21 nt siRNAs in Arabidopsis rosette leaves, 21 and 24 nt siRNAs accumulated to similar levels in Arabidopsis pollen grains, rice spikelets and maize anthers. We successfully detected two distinct double-stranded RNA (dsRNA)-cleaving activities that produced 21 and 24 nt RNAs in cell-free extracts prepared from various organs at different developmental stages of A. thaliana, Brassica rapa, rice and maize. Although DCL4 transcript was expressed more than DCL3 transcript in most organs, the 21 nt RNA-producing activity of DCL4 or its orthologs was very low and was 5- to 10-fold lower than the 24 nt RNA-producing activity of DCL3 or its orthologs particularly in leaves, indicating that DCL4 activity is negatively regulated translationally or post-translationally in leaves. High dicing activity of DCL3 and DCL4 was detected in immature inflorescences, developing seeds, germinating embryos and callus, all of which contain actively dividing cells. In various organs at different developmental stages, the size distribution of siRNAs was positively correlated with the dicing activity of two Dicers, DCL3 and DCL4, or their orthologs. Taken together, the size distribution of siRNAs in most organs is primarily determined by the dicing activity of DCL3 and DCL4.
Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Proteínas de Plantas/metabolismo , RNA Interferente Pequeno/metabolismo , Ribonuclease III/metabolismo , Arabidopsis/crescimento & desenvolvimento , Brassica rapa/crescimento & desenvolvimento , Brassica rapa/metabolismo , Flores/metabolismo , Oryza/crescimento & desenvolvimento , Oryza/metabolismo , Folhas de Planta/metabolismo , Sementes/metabolismo , Zea mays/crescimento & desenvolvimento , Zea mays/metabolismoRESUMO
The Chrysoviridae is a family of small, isometric, non-enveloped viruses (40 nm in diameter) with segmented dsRNA genomes (typically four segments). The genome segments are individually encapsidated and together comprise 11.5-12.8 kbp. The single genus Chrysovirus includes nine species. Chrysoviruses lack an extracellular phase to their life cycle; they are transmitted via intracellular routes within an individual during hyphal growth, in asexual or sexual spores, or between individuals via hyphal anastomosis. There are no known natural vectors for chrysoviruses. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the taxonomy of the Chrysoviridae, which is available at www.ictv.global/report/chrysoviridae.
Assuntos
Genoma Viral , Filogenia , Vírus de RNA/genética , RNA de Cadeia Dupla/genética , RNA Viral/genética , Vírion/genética , Ascomicetos/virologia , Basidiomycota/virologia , Hifas/virologia , Vírus de RNA/classificação , Vírus de RNA/ultraestrutura , Esporos Fúngicos/virologia , Terminologia como Assunto , Vírion/ultraestrutura , Replicação ViralRESUMO
In Arabidopsis thaliana, small interfering RNAs (siRNAs) generated by two Dicer isoforms, DCL3 and DCL4, function in distinct epigenetic processes, i.e. RNA-directed DNA methylation and post-transcriptional gene silencing, respectively. Plants often respond to their environment by producing a distinct set of small RNAs; however, the mechanism for controlling the production of different siRNAs from the same dsRNA substrate remains unclear. We established a simple biochemical method to visualize the dsRNA-cleaving activities of DCL3 and DCL4 in cell-free extracts prepared from Arabidopsis seedlings. Here, we demonstrate that different nutrient statuses of a host plant affect the post-translational regulation of the dicing activity of DCL3 and DCL4. Phosphate deficiency inhibited DCL3, and the activity of DCL3 was directly activated by inorganic phosphate. Sulfur deficiency inhibited DCL4 but not DCL3, and the activity of DCL4 was recovered by supplementation of the cell-free extracts with reductants containing a thiol group. Immunopurified DCL4 was activated by recombinant Arabidopsis thioredoxin-h1 with dithiothreitol. Therefore, DCL4 is subject to redox regulation. These results demonstrate that post-translational regulation of DCL activities fine-tunes the balance between branches of the gene silencing pathway according to the growth environment.
Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Fosfatos/metabolismo , Ribonuclease III/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Oxirredução , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/fisiologia , Ribonuclease III/genética , Enxofre/deficiência , Enxofre/metabolismoRESUMO
A double-stranded RNA (dsRNA) of approximately 15 kbp was isolated from asymptomatic winged bean (Psophocarpus tetragonolobus) plants. The size of the dsRNA, together with results of RT-PCR testing, suggested that it was the replicative form of a plant endornavirus. Cloning, sequencing, and sequence analyses confirmed the endornavirus nature of the dsRNA. Conserved motifs typical for endornaviruses were identified and their amino acid sequences compared with those of selected endornaviruses. Phylogenetic analyses revealed a close relationship with Bell pepper endornavirus, Phaseolus vulgaris endornavirus 2, and Hot pepper endornavirus. The dsRNA was present in most P. tetragonolobus genotypes tested. The virus was provisionally named Winged bean endornavirus 1 (WBEV-1).
Assuntos
Fabaceae/virologia , Vírus de RNA/classificação , Vírus de RNA/fisiologia , Clonagem Molecular , Biologia Computacional , Ordem dos Genes , Genoma Viral , Fases de Leitura Aberta , Filogenia , Doenças das Plantas/virologia , RNA Viral , Análise de Sequência de DNARESUMO
The model plant Arabidopsis thaliana has five double-stranded RNA-binding proteins (DRB1-DRB5), two of which, DRB1 and DRB4, are well characterized. In contrast, the functions of DRB2, DRB3 and DRB5 have yet to be elucidated. In this study, we tried to uncover their functions using drb mutants and DRB-over-expressed lines. In over-expressed lines of all five DRB genes, the over-expression of DRB2 or DRB3 (DRB2ox or DRB3ox) conferred a downward-curled leaf phenotype, but the expression profiles of ten small RNAs were similar to that of the wild-type (WT) plant. Phenotypes were examined in response to abiotic stresses. Both DRB2ox and DRB3ox plants exhibited salt-tolerance. When these plants were exposed to cold stress, drb2 and drb3 over-accumulated anthocyanin but DRB2ox and DRB3ox did not. Therefore, the over-expression of DRB2 or DRB3 had pleiotropic effects on host plants. Microarray and deep-sequencing analyses indicated that several genes encoding key enzymes for anthocyanin biosynthesis, including chalcone synthase (CHS), dihydroflavonol reductase (DFR) and anthocyanidin synthase (ANS), were down-regulated in DRB3ox plants. When DRB3ox was crossed with the pap1-D line, which is an activation-tagged transgenic line that over-expresses the key transcription factor PAP1 (Production of anthocyanin pigmentation1) for anthocyanin biosynthesis, over-expression of DRB3 suppressed the expression of PAP1, CHS, DFR and ANS genes. DRB3 negatively regulates anthocyanin biosynthesis by modulating the level of PAP1 transcript. Since two different small RNAs regulate PAP1 gene expression, a possible function of DRB3 for small RNA biogenesis is discussed.
Assuntos
Antocianinas/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Regulação da Expressão Gênica de Plantas , RNA de Cadeia Dupla/metabolismo , Proteínas de Ligação a RNA/metabolismo , Fatores de Transcrição/genética , Antocianinas/análise , Arabidopsis/fisiologia , Temperatura Baixa , Expressão Gênica , Perfilação da Expressão Gênica , Genótipo , Análise de Sequência com Séries de Oligonucleotídeos , Proteínas Associadas a Pancreatite , Fenótipo , Folhas de Planta/genética , Folhas de Planta/fisiologia , RNA de Cadeia Dupla/genética , Proteínas de Ligação a RNA/genética , Tolerância ao Sal , Análise de Sequência de DNA , Estresse FisiológicoRESUMO
Strains of the phytopathogenic fungus Alternaria spp. have been found to contain a variety of double-stranded RNA (dsRNA) elements indicative of mycovirus infection. Here, we report the molecular characterization of a novel dsRNA mycovirus, Alternaria arborescens victorivirus 1 (AaVV1), from A. arborescens, the tomato pathotype of A. alternata. Using next-generation sequencing of dsRNA purified from an A. arborescens strain from the United States of America, we found that the AaVV1 genome is 5203 bp in length and contains two open reading frames (ORF1 and 2) that overlap at the tetranucleotide AUGA. Proteins encoded by ORF1 and ORF2 showed significant similarities to the coat protein (CP) and the RNA-dependent RNA polymerase (RdRp), respectively, of dsRNA mycoviruses of the genus Victorivirus. Pairwise comparisons and phylogenetic analysis of the deduced amino acid sequences of both CP and RdRp indicated that AaVV1 is a member of a distinct species of the genus Victorivirus in the family Totiviridae.
Assuntos
Alternaria/virologia , Micovírus/genética , Totiviridae/genética , Alternaria/patogenicidade , Proteínas do Capsídeo/genética , Micovírus/classificação , Micovírus/isolamento & purificação , Genoma Viral , Fases de Leitura Aberta , Filogenia , RNA Viral/química , RNA Viral/genética , RNA Polimerase Dependente de RNA/genética , Totiviridae/classificação , Totiviridae/isolamento & purificaçãoRESUMO
The phytopathogenic fungus Alternaria spp. contains a variety of double-stranded RNA (dsRNA) elements of different sizes. Detailed analysis of next-generation sequencing data obtained using dsRNA purified from Alternaria arborescens, from which we had previously found Alternaria arborescens victorivirus 1, revealed the presence of another mycoviral-like dsRNA of approximately 2.5 kbp in length. When using the fungal mitochondrial genetic code, this dsRNA has a single open reading frame that potentially encodes an RNA-dependent RNA polymerase (RdRp) with significant to sequence similarity to those of viruses of the genus Mitovirus. Moreover, both the 5'- and 3'-untranslated regions have the potential to fold into stable stem-loop structures, which is characteristic of mitoviruses. Pairwise comparisons and phylogenetic analysis of the deduced amino acid sequences of RdRp indicated that the virus we identified in A. arborescens is a distinct member of the genus Mitovirus in the family Narnaviridae, designated as "Alternaria arborescens mitovirus 1" (AaMV1).
Assuntos
Alternaria/virologia , Micovírus/genética , Genoma Viral , FilogeniaRESUMO
Magnaporthe oryzae chrysovirus 1 (MoCV1) is a mycovirus with a dsRNA genome that infects the rice blast fungus Magnaporthe oryzae and impairs its growth. To date, MoCV1 has only been found in Vietnamese isolates of M. oryzae, and the distribution of this virus in M. oryzae isolates from other parts of the world remains unknown. In this study, using a one-step reverse transcription PCR (RT-PCR) assay, we detected a MoCV1-related virus in M. oryzae in Japan (named MoCV1-AK) whose sequence shares considerable similarity with that of the MoCV1 Vietnamese isolate. To establish a system for a comprehensive survey of MoCV1 infection in the field, we developed a reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay for direct detection of the virus. The sensitivity of the RT-LAMP assay was at least as high as that of the one-step RT-PCR assay. In addition, we detected MoCV1-AK in M. oryzae-infected oatmeal agar plates and lesions on rice leaves using the RT-LAMP assay without dsRNA extraction, by simple sampling with a toothpick. Preliminary screening of MoCV1 in Japanese M. oryzae isolates indicated that MoCV1 is currently distributed in rice fields in Japan. Our results provide a first example of the application of RT-LAMP for the detection of mycoviruses, which will accelerate surveys for mycovirus infection.
Assuntos
Micovírus/isolamento & purificação , Magnaporthe/virologia , Técnicas de Amplificação de Ácido Nucleico/métodos , Vírus de RNA/isolamento & purificação , Sequência de Bases , Análise por Conglomerados , Micovírus/genética , Japão , Magnaporthe/crescimento & desenvolvimento , Dados de Sequência Molecular , Oryza/microbiologia , Filogenia , Vírus de RNA/genética , RNA Viral/genética , Transcrição Reversa , Análise de Sequência de DNA , Homologia de Sequência , Temperatura , Fatores de TempoRESUMO
In Arabidopsis thaliana, Dicer-like 3 (DCL3) and Dicer-like 4 (DCL4) cleave long, perfect double-stranded RNAs (dsRNAs) into 24 and 21 nucleotides (nt) small interfering RNAs, respectively, which in turn function in RNA-directed DNA methylation and RNA interference, respectively. To reveal how DCL3 and DCL4 individually recognize long perfect dsRNAs as substrates, we biochemically characterized DCL3 and DCL4 and compared their enzymatic properties. DCL3 preferentially cleaves short dsRNAs with 5' phosphorylated adenosine or uridine and a 1 nt 3' overhang, whereas DCL4 cleaves long dsRNAs with blunt ends or with a 1 or 2 nt 3' overhang with similar efficiency. DCL3 produces 24 nt RNA duplexes with 2 nt 3' overhangs by the 5' counting rule. Inorganic phosphate, NaCl and KCl enhance DCL3 activity but inhibit DCL4 activity. These results indicate that plants use DCLs with distinct catalytic profiles to ensure each dsRNA substrate generates only a specific length of siRNAs that trigger a unique siRNA-mediated response.
Assuntos
Proteínas de Arabidopsis/metabolismo , RNA de Cadeia Dupla/metabolismo , Ribonuclease III/metabolismo , Adenosina/metabolismo , Fosforilação , Clivagem do RNA , RNA de Cadeia Dupla/química , Especificidade por Substrato , Uridina/metabolismoRESUMO
A novel dsRNA virus was identified from the arboreal ant Camponotus yamaokai. The complete nucleotide sequence analysis of the virus revealed that the virus consisted of 5704 bp with two ORFs. ORF1 (3084 nt) encoded a putative capsid protein. ORF2 (1977 nt) encoded a viral RNA-dependent RNA polymerase (RdRp). ORF2 could be translated as a fusion with the ORF1 product by a - 1 frameshift in the overlapping ORF1. Phylogenetic analyses based on the RdRp revealed that the virus from C. yamaokai was most likely a novel totivirus, but it was not closely related to the previously known totiviruses in arthropods. Transmission electron microscopy revealed isometric virus particles of ~30ânm diameter in the cytoplasm, which was consistent with the characteristics of the family Totiviridae. The virus was detected by reverse transcription-PCR in all caste members and developmental stages of ants, including eggs, larvae, pupae, adult workers, alates (male and female) and queens. To our knowledge, this is the first report of a member of the family Totiviridae in a hymenopteran; the virus was designated Camponotus yamaokai virus.
Assuntos
Formigas/virologia , Genoma Viral , Vírus de RNA/classificação , Vírus de RNA/isolamento & purificação , RNA de Cadeia Dupla/genética , RNA Viral/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Análise por Conglomerados , Feminino , Masculino , Microscopia Eletrônica de Transmissão , Dados de Sequência Molecular , Fases de Leitura Aberta , Filogenia , Vírus de RNA/genética , Vírus de RNA/ultraestrutura , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNA , Homologia de Sequência , Vírion/ultraestruturaRESUMO
Hydrogen sulfide (H2S) is a novel gasotransmitter that plays multiple biological roles in various body systems. In addition to its endogenous production, H2S is produced by bacteria colonizing digestive organs, including the oral cavity. H2S was previously shown to enhance pro-apoptotic effects in cancer cell lines, although the mechanisms involved remain unclear. To properly assess the anti-cancer effects of H2S, however, investigations of apoptotic effects in normal cells are also necessary. The aims of this study were (1) to compare the susceptibility to H2S-induced apoptosis between the oral cancer cell line Ca9-22 and oral keratinocytes that were derived from healthy gingiva, and (2) to identify candidate genes involved in the induction of apoptosis by H2S. The susceptibility to H2S-induced apoptosis in Ca9-22 cells was significantly higher than that in keratinocytes. H2S exposure in Ca9-22 cells, but not keratinocytes, enhanced the expression of pleckstrin homology-like domain, family A, member 1 (PHLDA1), which was identified through a differential display method. In addition, PHLDA1 expression increased during actinomycin D-induced apoptosis in Ca9-22 cells. Knockdown of PHLDA1 expression by small interfering RNA in Ca9-22 cells led to expression of active caspase 3, thus indicating apoptosis induction. The tongue cancer cell line SCC-25, which expresses PHLDA1 at a high level, showed similar effects. Our data indicate that H2S is an anti-cancer compound that may contribute to the low incidence of oral cancer. Furthermore, we demonstrated the role of PHLDA1 as an apoptosis suppressor.
Assuntos
Apoptose/efeitos dos fármacos , Apoptose/genética , Resistencia a Medicamentos Antineoplásicos/genética , Sulfeto de Hidrogênio/farmacologia , Queratinócitos/efeitos dos fármacos , Neoplasias Bucais/genética , Fatores de Transcrição/genética , Sequência de Bases , Células Cultivadas , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Queratinócitos/metabolismo , Queratinócitos/patologia , Dados de Sequência Molecular , Mucosa Bucal/efeitos dos fármacos , Mucosa Bucal/metabolismo , Mucosa Bucal/patologia , Neoplasias Bucais/patologia , RNA Interferente Pequeno/farmacologia , Fatores de Transcrição/metabolismoRESUMO
A putative new endornavirus was isolated from Malabar spinach (Basella alba). The viral dsRNA consisted of 14,027 nt with a single ORF that coded for a polyprotein of 4,508 aa. The genome organization was similar to that of four other endornaviruses. Conserved domains for helicase-1, capsular synthase, UDP-glucose-glycosyltransferase (UGT), and RdRp were detected. Infected plants were phenotypically undistinguishable from healthy ones. The name Basella alba endornavirus is proposed for the virus isolated from Malabar spinach.
Assuntos
Genoma Viral , Vírus de Plantas/classificação , Vírus de Plantas/isolamento & purificação , Vírus de RNA/classificação , Vírus de RNA/isolamento & purificação , RNA Viral/genética , Traqueófitas/virologia , Análise por Conglomerados , Dados de Sequência Molecular , Fases de Leitura Aberta , Filogenia , Vírus de Plantas/genética , Vírus de RNA/genética , Análise de Sequência de DNA , Homologia de Sequência , Proteínas Virais/genéticaRESUMO
Magnaporthe oryzae chrysovirus 1 strain A (MoCV1-A) is the causal agent of growth repression and attenuated virulence (hypovirulence) of the rice blast fungus, M. oryzae. We have previously reported that heterologous expression of MoCV1-A ORF4 in Saccharomyces cerevisiae results in growth defects, a large central vacuole and other cytological changes. In this study, the effects of open reading frame (ORF) 4 expression in Cryptococcus neoformans, a human pathogenic fungus responsible for severe opportunistic infection, were investigated. Cells expressing the ORF4 gene in C. neoformans showed remarkably enlarged vacuoles, nuclear diffusion and a reduced growth rate. In addition, expression of ORF4 apparently suppressed formation of the capsule that surrounds the entire cell wall, which is one of the most important components of expression of virulence. After 5-fluoroorotic acid treatment of ORF4-expressing cells to remove the plasmid carrying the ORF4 gene, the resultant plasmid-free cells recovered normal morphology and growth, indicating that heterologous expression of the MoCV1-A ORF4 gene induces negative effects in C. neoformans. These data suggest that the ORF4 product is a candidate for a pharmaceutical protein to control disease caused by C. neoformans.
Assuntos
Cryptococcus neoformans/citologia , Cryptococcus neoformans/crescimento & desenvolvimento , Genes Virais , Magnaporthe/virologia , Vírus de RNA/genética , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/toxicidade , Cryptococcus neoformans/genética , Organelas/ultraestrutura , Vírus de RNA/isolamento & purificação , Proteínas Recombinantes/genéticaRESUMO
We report here the whole-genome sequence of the Chlamydia psittaci NRM_5 strain isolated from the fecal samples of wild Indian ring-necked parakeet (Psittacula krameri manillensis) in Japan. The sequence type is ST35, which is known to be associated with pigeons and doves, indicating the potential for transmission among bird species.
RESUMO
Talaromyces spp. have a worldwide distribution, are ecologically diverse and have been isolated from numerous different substrates. Talaromyces spp. are considered biotechnologically important due to their ability to produce a range of enzymes and pigments. Talaromyces pinophilus, belonging to genus Talaromyces and family Trichocomaceae, is known for producing several important bioactive metabolites. Here we report the isolation and characterisation of a partitivirus from T. pinophilus which we have nominated Talaromyces pinophilus partitivirus-1 (TpPV-1). TpPV-1 possesses a genome consisting of three double stranded (ds) RNA segments i.e., dsRNAs1-3, 1824 bp, 1638 bp and 1451 bp respectively, which are encapsidated in icosahedral particles 35 nm in diameter. Both dsRNA1 and dsRNA2 contain a single open reading frame (ORF) encoding respectively a 572 amino acid (aa) protein of 65 kDa and a 504 aa protein of 50 kDa. The third segment (dsRNA3) is potentially a satellite RNA. Phylogenetic analysis revealed that the TpPV-1 belongs to the family Partitiviridae in the proposed genus Zetapartitivirus. TpPV-1 infection decreases the mycelial growth rate of the host fungus and alters pigmentation as indicated by time course experiments performed on a range of different solid media comparing virus-infected and virus-free isogenic lines. This is the first report of mycovirus infection in T. pinophilus and may provide insights into understanding the effect of the mycovirus on the production of enzymes and pigments by the host fungus.
Assuntos
Micovírus , Vírus de RNA , Talaromyces , Talaromyces/genética , Talaromyces/metabolismo , Filogenia , RNA de Cadeia Dupla/metabolismo , Genoma Viral , RNA Viral/genética , RNA Viral/metabolismo , Fases de Leitura AbertaRESUMO
Two high-molecular-mass dsRNAs of approximately 14 and 15 kbp were isolated from the common bean (Phaseolus vulgaris) cultivar Black Turtle Soup. These dsRNAs did not appear to cause obvious disease symptoms, and were transmitted through seeds at nearly 100% efficiency. Sequence information indicates that they are the genomes of distinct endornavirus species, for which the names Phaseolus vulgaris endornavirus 1 (PvEV-1) and Phaseolus vulgaris endornavirus 2 (PvEV-2) are proposed. The PvEV-1 genome consists of 13,908 bp and potentially encodes a single polyprotein of 4496 aa, while that of PvEV-2 consists of 14â820 bp and potentially encodes a single ORF of 4851 aa. PvEV-1 is more similar to Oryza sativa endornavirus, while PvEV-2 is more similar to bell pepper endornavirus. Both viruses have a site-specific nick near the 5' region of the coding strand, which is a common property of the endornaviruses. Their polyproteins contain domains of RNA helicase, UDP-glycosyltransferase and RNA-dependent RNA polymerase, which are conserved in other endornaviruses. However, a viral methyltransferase domain was found in the N-terminal region of PvEV-2, but was absent in PvEV-1. Results of cell-fractionation studies suggested that their subcellular localizations were different. Most endornavirus-infected bean cultivars tested were co-infected with both viruses.