RESUMO
The tropics were long considered to have few ectomycorrhizal fungi, presumably due to a paucity of ectomycorrhizal host plants relative to higher-latitude ecosystems. However, an increase in research in tropical regions over the past 30 years has greatly expanded knowledge about the occurrence of tropical ectomycorrhizal fungi. To assess their broad biogeographic and diversity patterns, we conducted a comprehensive review and quantitative data analysis of 49 studies with 80 individual data sets along with additional data from GlobalFungi to elucidate tropical diversity patterns and biogeography of ectomycorrhizal fungi across the four main tropical regions: the Afrotropics, the Neotropics, Southeast Asia, and Oceania. Generalized linear models were used to explore biotic and abiotic influences on the relative abundance of the 10 most frequently occurring lineages. We also reviewed the available literature and synthesized current knowledge about responses of fungi to anthropogenic disturbances, and their conservation status and threats. We found that /russula-lactarius and /tomentella-thelephora were the most abundant lineages in the Afrotropics, the Neotropics, and Southeast Asia, whereas /cortinarius was the most abundant lineage in Oceania, and that /russula-lactarius, /inocybe, and /tomentella-thelephora were the most species-rich lineages across all of the tropical regions. Based on these analyses, we highlight knowledge gaps for each tropical region. Increased sampling of tropical regions, collaborative efforts, and use of molecular methodologies are needed for a more comprehensive view of the ecology and diversity of tropical ectomycorrhizal fungi.
Assuntos
Agaricales , Basidiomycota , Micorrizas , Micorrizas/genética , Ecossistema , Filogenia , Fungos , Basidiomycota/genética , Plantas/microbiologiaRESUMO
Bioactive secondary metabolite production from endophytic fungi has gained a recurring research focus in recent decades as these microorganisms represent an unexplored biological niche for their diverse biotechnological potential. Despite this focus, studies involving tropical endophytes remain scarce, particularly those isolated from medicinal plants of these ecosystems. In addition, the state of the art of the pharmaceutical industry has experienced stagnation in the past 30years, which has pushed pathogenic infections to get one step ahead, resulting in the development of resistance to existing treatments. Here, five fungal endophytes were isolated from the medicinal plant Otoba gracilipes (Myristicaceae), which corresponded to the genera Xylaria and Diaporthe, and screened to demonstrate the promissory potential of these microorganisms for producing bioactive secondary metabolites with broad-spectrum antibacterial activities. Thus, the evaluation of crude organic extracts obtained from the mycelia and exhaust medium allowed the elucidation of Xylaria sp. and Diaporthe endophytica potential toward providing crude extracellular extracts with promising bioactivities against reference strains of Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 25923), according to the determined half-maximum inhibitory concentration (IC50) with values down to 3.91 and 10.50mg/ml against each pathogen, respectively. Follow-up studies provided insights into the polarity nature of bioactive compounds in the crude extracts through bioactivity guided fractionation using a polymeric resin absorbent alternative extraction procedure. In addition, evaluation of the co-culturing methods demonstrated how this strategy can enhance endophytes biosynthetic capacity and improve their antibacterial potential with a 10-fold decrease in the IC50 values against both pathogens compared to the obtained values in the preliminary evaluations of Xylaria sp. and D. endophytica crude extracts. These results support the potential of Colombian native biodiversity to provide new approaches concerning the global emergence of antibiotics resistance and future production of undiscovered compounds different from the currently used antibiotics classes and simultaneously call for the value of preserving native habitats due to their promising ecosystemic applications in the biotechnological and pharmaceutical industries.
RESUMO
Aromas and flavours can be produced from fungi by either de novo synthesis or biotransformation processes. Herein, the biocatalytic potential of seven basidiomycete species from Colombia fungal strains isolated as endophytes or basidioma was evaluated. Ganoderma webenarium, Ganoderma chocoense, and Ganoderma stipitatum were the most potent strains capable of decolourizing ß,ß-carotene as evidence of their potential as biocatalysts for de novo aroma synthesis. Since a species' biocatalytic potential cannot solely be determined via qualitative screening using ß,ß-carotene biotransformation processes, we focused on using α-pinene biotransformation with mycelium as a measure of catalytic potential. Here, two strains of Trametes elegans-namely, the endophytic (ET-06) and basidioma (EBB-046) strains-were screened. Herein, T. elegans is reported for the first time as a novel biocatalyst for the oxidation of α-pinene, with a product yield of 2.9 mg of cis-Verbenol per gram of dry weight mycelia used. The EBB-046 strain generated flavour compounds via the biotransformation of a Cape gooseberry medium and de novo synthesis in submerged cultures. Three aroma-producing compounds were identified via GC-MS-namely, methyl-3-methoxy-4H-pyran-4-one, hexahydro-3-(methylpropyl)-pyrrolo[1,2-a]pyrazine-1,4-dione, and hexahydro-3-(methylphenyl)-pyrrolo[1,2-a]pyrazine-1,4-dione.
Assuntos
Basidiomycota/metabolismo , Biocatálise , Odorantes/análise , Paladar , Animais , Biotransformação , Colômbia , Compostos Orgânicos Voláteis/química , Compostos Orgânicos Voláteis/metabolismoRESUMO
The neotropical biogeographic zone is a 'hot spot' of global biodiversity, especially for insects. Fungal pathogens of insects appear to track this diversity. However, the integration of this unique component of fungal diversity into molecular phylogenetic analyses remains sparse. The entomopathogenic fungal genus Ophiocordyceps is species rich in this region with the first descriptions dating to the early nineteenth century. In this study, material from various ecosystems throughout Colombia and Ecuador was examined. Molecular phylogenetic analyses of five nuclear loci including SSU, LSU, TEF, RPB1, and RPB2 were conducted alongside a morphological evaluation. Thirty-five specimens were examined representing fifteen different species of Ophiocordyceps, and five new species, Ophiocordyceps blattarioides, Ophiocordyceps tiputini, Ophiocordyceps araracuarensis, Ophiocordyceps fulgoromorphila, and Ophiocordyceps evansii, were described. An accurate identification of the host allowed us to conclude that host identity and host habitat are positively correlated with phylogenetic species of Ophiocordyceps and are probably strong drivers for speciation of neotropical entomopathogenic fungi.