RESUMO
A total of 53 anamorphic strains of Brazilian Cordyceps species currently maintained in a government-owned culture collection, were reassessed for diversity and species identity using multi-loci-based phylogenetic methods. The strains used in this study were originally obtained from soil samples or were isolated from insects of the orders Hemiptera, Lepidoptera, Coleoptera and Diptera, mostly from agricultural sites. A Bayesian phylogenetic tree was constructed based on a concatenation of five loci (ITS, LSU, RPB1, RPB2 and TEF). In a few cases of ambiguity, morphological traits were also considered for species delimitations. Considerable variability within the set of strains was detected and six Cordyceps species were identified: C. amoenerosea, C. fumosorosea, C. javanica, C. tenuipes and, for the first time, C. brevistroma and C. spegazzinii are reported in Brazil. Four other taxonomically equivocal groups, closely related to other known taxa (C. amoenerosea, C. cateniannulata, C. polyarthra and C. spegazzinii), were also recognized, although further studies will be required to confirm their identifications or their descriptions as new species. Cordyceps javanica was the most common species in our dataset, originally isolated from soil and several different insect orders, and includes 17 strains from the whitefly, Bemisia tabaci. Interestingly, strains previously identified as C. fumosorosea based on morphology and growth characteristics, were shown to be C. javanica, including the active ingredients of some commercial mycoinsecticides. Cordyceps farinosa, usually mentioned in the literature as occurring in Brazil, was not found in our study. Since most strains were from insect crop pests, further studies with hosts from non-agricultural settings or from environmental samples would be advisable for a deeper understanding of the occurrence of anamorphic Cordyceps in Brazil.
Assuntos
Cordyceps , Hemípteros , Hypocreales , Animais , Cordyceps/genética , Brasil , Filogenia , Teorema de Bayes , InsetosRESUMO
Cordyceps s.l. is a paraphyletic group of ascomycete fungi that exhibit multifunctional lifestyles, that is, as saprotrophs, endophytes, and pathogens of insects, spiders, fungi, and grasses. The family Cordycipitaceae includes macroscopically similar species that have been erroneously considered to be conspecific with Cordyceps militaris. In this study, we describe a new species within the C. militaris complex that is distributed in the Quercus-Pinus forests of central Mexico on the basis of its morphology, phylogenetic relationships, and life cycle. Phylogenetically, Cordyceps mexicana is a well-supported new sister species of the C. militaris complex. It is distinguished by the morphology of its conidiophore, host association, and geographic distribution. This species parasitizes pupae of Paradirphia sp. (Lepidoptera: Saturniidae: Hemileucinae) and might be macroscopically confused with C. militaris. Its stromata are large, can measure up to 10 cm in length, and the fertile part is always bright yellow. This species develops whitish mycelial cords that emerge from the stromata and grow toward the host. Microscopically, it develops asci with filiform ascospores disarticulating in part-spores. Its life cycle and geographic distribution are also discussed.
Assuntos
Cordyceps , Mariposas , Pinus , Quercus , Animais , Cordyceps/genética , Florestas , México , FilogeniaRESUMO
Culturing the entomopathogenic fungus, Beauveria bassiana, under high glucose concentrations coupled with high aeration results in a fungal developmental shift from hyphal growth to mostly blastospores (yeast-like cells). The underlying molecular mechanisms involved in this shift remain elusive. A systematic transcriptome analysis of the differential gene expression was preformed to uncover the fungal transcriptomic response to osmotic and oxidative stresses associated with the resulting high blastospore yield. Differential gene expression was compared under moderate (10% w/v) and high (20% w/v) glucose concentrations daily for three days. The RNAseq-based transcriptomic results depicted a higher proportion of downregulated genes when the fungus was grown under 20% glucose than 10%. Additional experiments explored a broader glucose range (4, 8, 12, 16, 20% w/v) with phenotype assessment and qRT-PCR transcript abundance measurements of selected genes. Antioxidant, calcium transport, conidiation, and osmosensor-related genes were highly upregulated in higher glucose titers (16-20%) compared to growth in lower glucose (4-6%) concentrations. The class 1 hydrophobin gene (Hyd1) was highly expressed throughout the culturing. Hyd1 is known to be involved in spore coat rodlet layer assembly, and indicates that blastospores or another cell type containing hydrophobin 1 is expressed in the haemocoel during the infection process. Furthermore, we found implications of the HOG signaling pathway with upregulation of homologous genes Ssk2 and Hog1 for all fermentation time points under hyperosmotic medium (20% glucose). These findings expand our knowledge of the molecular mechanisms behind blastospore development and may help facilitate large-scale industrial production of B. bassiana blastospores for pest control applications.
Assuntos
Beauveria , Beauveria/genética , Meios de Cultura , Fermentação , Perfilação da Expressão Gênica , Glucose , Esporos FúngicosRESUMO
Laccases are ligninolytic enzymes produced by different microorganisms, especially by fungi such as the white-rot fungus Pleurotus ostreatus. Chemical inductors have been used to promote laccase secretion due to the application of these enzymes in lignocellulosic biomass pretreatment. Cordyceps nidus ANDES-F1080 was previously described as a source of bioactive compounds that could influence the enzymatic production system of other fungi. For that reason, this study evaluates the effect of C. nidus' ANDES-F1080 extracts on the laccase activity of P. ostreatus ANDES-F515. To achieve this objective, C. nidus ANDES-F1080 was grown in four different substrates: two artificial-based and two natural-based culture media. Metabolites were extracted from C. nidus ANDES-F1080 using water and methanol as solvents. Biochemical characterization of these extracts was performed to complement the analysis of their effect on laccase activity. Our results revealed an enhancement on the laccase activity of P. ostreatus ANDES-F515â¯grown in natural-based cultures when C. nidus' ANDES-F1080 extracts were supplemented. The best laccase activities registered values around 10,575⯱â¯813 U·L-1.
RESUMO
We combined matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) along with sequencing of the B locus intergenic region (Bloc) to assess the diversity of Brazilian species within the anamorphic genus Beauveria. A total of 121 strains maintained in a government-owned culture collection and isolated from a range of hosts/substrates over a long time span (1981-2015) were assessed. Strains were collected in five of six Brazilian biomes, mostly in the Atlantic Forest (42.2%) and Cerrado (29.8%), primarily from insect pests of crops. All strains were subjected to MS, and those not accurately identified by this technique were genomically analyzed. Among the outcomes of this study, four taxa from the genus Beauveria were recognized, with the great majority of strains belonging to B. bassiana s.str. (93.4%), followed by B. caledonica (2.5%), B. pseudobassiana (2.5%) and B. amorpha (1.6%). B. bassiana s.str. was found in all biomes and isolated from a wide range of hosts/substrates. Due to low numbers, associations of the remaining Beauveria species with specific hosts or habitats/biomes were not clear, except that all three B. caledonica strains were found only in the Cerrado biome and were associated with adults of the banana weevil, Cosmopolites sordidus (Col.:Curculionidae). B. pseudobassiana is reported for the first time on the South American continent, in a subtropical region and from two insect orders not yet associated with this taxon. We also showed that some strains previously ascribed to B. brongniartii were misidentifications. The biodiversity of Beauveria analyzed in our study was comparatively low. The geographic origins of strains used in our study were biased towards biomes with intense human interventions. Future surveys on more conserved, less environmentally disturbed biomes, such as Caatinga, Pampa, Pantanal, and Amazon are needed for a more comprehensive picture of the diversity of Beauveria and related genera in Brazil.
Assuntos
Beauveria/classificação , Interações Hospedeiro-Patógeno , Micobioma , Beauveria/genética , Brasil , DNA Fúngico/análise , DNA Intergênico/análise , Filogenia , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por MatrizRESUMO
BACKGROUND: Microbial surfactants are multifunctional surface-active molecules that have been overlooked in formulating microbial biopesticides. We report a novel approach using the biosurfactant rhamnolipid (RML) against the destructive cosmopolitan insect pest Bemisia tabaci, as well as the combined action of RML with aerial conidia of two entomopathogenic fungi, Cordyceps javanica and Beauveria bassiana. RML was also tested as a suspension agent to improve the recovery rate of conidia from solid substrate for fungal preparations. RESULTS: The recovery rate of conidia increased dramatically (two to five times) with RML compared with a standard surfactant (Tween 80). Spraying solutions of 0.075% and 0.1% (w/v) RML on B. tabaci third instar nymphs induced 100% mortality within 4 days. Conidial suspensions at 5 × 106 conidia/mL amended with RML at 0.01% or 0.05% markedly increased nymphal mortalities and considerably reduced LC50 . Conidial suspensions of B. bassiana with 0.05% RML added were more effective against whitefly nymphs (87.3% mortality) than C. javanica + RML (51.4% mortality). CONCLUSION: Our results show that this bacterium-based RML improved the recovery rate of hydrophobic conidia, and that mixtures of RML with fungal spore suspensions increased their insecticidal activity. © 2019 Society of Chemical Industry.
Assuntos
Beauveria/fisiologia , Cordyceps/fisiologia , Glicolipídeos/farmacologia , Hemípteros , Inseticidas/farmacologia , Controle Biológico de Vetores/métodos , Tensoativos/farmacologia , Animais , Hemípteros/efeitos dos fármacos , Hemípteros/crescimento & desenvolvimento , Hemípteros/microbiologia , Ninfa/efeitos dos fármacos , Ninfa/crescimento & desenvolvimento , Ninfa/microbiologia , Esporos Fúngicos/fisiologiaRESUMO
Cordyceps tenuipes is an entomopathogenic fungus that infects mostly pupae of several lepidopteran families. In Colombia the species has been reported in non-disturbed tropical rain forests and more recently in butterfly gardens. The aim of this study was to assess the genetic diversity in populations of C. tenuipes present in natural (forests) and artificial (e.g. butterfly gardens) environments in the department of Quindío, Colombia, using three molecular nuclear markers ITS, TEF-1α and RPB1. All the samples evaluated corresponded morphologically and phylogenetically to C. tenuipes. The butterfly garden of Quindio Botanical Garden (QBG) showed the highest genetic diversity among all sampling localities and was very similar to that of its adjacent forest. The Amaranta Butterfly Garden (ABG), located north of QBG, showed lower genetic diversity as well as little genetic differentiation with QBG, consistent with the hypothesis of a pathogen transfer from QBG to ABG. Higher FST values were observed for TEF-1α and ITS, revealing genetic differentiation between all demes and the southern forest population. Our research constitutes the first study of the intraspecific diversity of C. tenuipes in Colombia and can serve as the first step in identifying diversity reservoirs and management of epizootic episodes caused by this fungal species.
Assuntos
Borboletas/microbiologia , Cordyceps/genética , Cordyceps/patogenicidade , Florestas , Jardins , Animais , Colômbia , Variação Genética , FilogeniaRESUMO
The present study aimed to add value to palm oil by-products as substrates to efficiently produce conidia of Beauveria bassiana and Isaria javanica (Hypocreales: Cordycipitaceae) for biological control of the whitefly Bemisia tabaci (Hemiptera: Aleyrodidae), through a solid-state fermentation process using palm kernel cake and palm fiber as nutrient source and solid matrix, respectively. The optimum culture conditions yielded high concentrations of viable conidia after air-drying, when the fungi were grown on palm kernel cake (B. bassiana 7.65 × 109 and I. javanica 2.91 × 109 conidia g-1 dry substrate) after 6 days under optimal growth conditions set to 60% substrate moisture and 32 °C. Both fungal strains exhibited high efficacy against third-instar whitefly nymphs, inducing mortality up to 62.9 and 56.6% by B. bassiana and I. javanica, respectively, assessed after 9 days post-application in a screenhouse. Furthermore, we noted that insect mortality was strongly correlated with high atmospheric moisture, while B. bassiana appeared to require shorter accumulative hours under high moisture to kill whitefly nymphs compared to I. javanica. Our results underpin a feasible and cost-effective mass production method for aerial conidia, using palm kernel as the main substrate in order to produce efficacious fungal bioinsecticides against an invasive whitefly species in Brazil. Finally, our fermentation process may offer a sustainable and cost-effective means to produce eco-friendly mycoinsecticides, using an abundant agro-industrial by-product from Brazil that will ultimately assist in the integrated management of agricultural insect pests.
Assuntos
Beauveria/metabolismo , Cordyceps/metabolismo , Análise Custo-Benefício , Resíduos Industriais , Inseticidas/metabolismo , Animais , Beauveria/crescimento & desenvolvimento , Biotransformação , Brasil , Cordyceps/crescimento & desenvolvimento , Fermentação , Hemípteros/efeitos dos fármacos , Inseticidas/farmacologia , Ninfa/efeitos dos fármacos , Análise de Sobrevida , TemperaturaRESUMO
Nine previously undescribed depsidones (simplicildones A-I) and one previously undescribed α-pyrone (simplicilopyrone) were isolated from the endophytic fungus Simplicillium sp. PSU-H41 along with 11 known compounds. Their structures were established by extensive spectroscopic analysis. Simplicildone A and known botryorhodine C displayed weak antibacterial against Staphylococcus aureus with equal MIC values of 32 µg/mL. Additionally, botryorhodine C was active against methicillin-resistant S. aureus with the same MIC value. Simplicildone C exhibited weak antifungal activity against Cryptococcus neoformans with an MIC value of 32 µg/mL. In addition, simplicildones A and C and botryorhodine C were noncytotoxic against noncancerous Vero cells.
Assuntos
Antibacterianos/isolamento & purificação , Antifúngicos/isolamento & purificação , Depsídeos/isolamento & purificação , Euphorbiaceae/química , Hevea/química , Lactonas/isolamento & purificação , Pironas/isolamento & purificação , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Antifúngicos/química , Antifúngicos/farmacologia , Chlorocebus aethiops , Cryptococcus neoformans/efeitos dos fármacos , Depsídeos/química , Depsídeos/farmacologia , Lactonas/química , Lactonas/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Folhas de Planta/química , Pironas/química , Pironas/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Células VeroRESUMO
AIMS: We report the first occurrence of an epizootic of the ascomycete fungus, Isaria tenuipes (teleomorph Cordyceps takaomontana), on the ocola skipper Panoquina ocola (Lepidoptera: Hesperiidae), an insect pest affecting rice in Brazil. METHODS AND RESULTS: Field surveys in flooded rice fields in the state of Goiás in Brazil were conducted, and a fungal pathogen of a caterpillar pest (P. ocola) was serendipitously found. This fungus inflicted high infection levels (average 86·2%) mainly to the pupal stage during warm, humid growing conditions. Typically, mycosed pupal cadavers produced milky-white to pale yellow synnemata bearing an average of 1·1 ± 0·2 × 109 conidia per cadaver. Based on phylogenetic analysis using beta-tubulin gene sequences, we confirmed that all 12 isolates obtained from field-mummified pupae were identifiable as I. tenuipes. CONCLUSIONS: Our data expand our knowledge on the host and geographical ranges of this mycopathogen and underscore its epizootic potential to affect a lepidopterous insect pest on rice in Brazil. This finding may facilitate the exploitation of this fungus as a mycoinsecticide. SIGNIFICANCE AND IMPACT OF THE STUDY: Isaria tenuipes may be used as an effective and environmentally friendly bioinsecticide against agricultural caterpillar pests due to its epizootic potential, as well as explored for medicinal purposes by pharmaceutical industry.