RESUMEN
Identification of Fusarium species associated with diseases symptoms in plants is an important step toward understanding the ecology of plant-fungus associations. In this study, four Fusarium isolates were obtained from root rot of Oryza sativa L. in Izeh (southwest of Iran) and identified based on phylogenetic analyses combined with morphology. Phylogenetic analyses based on combined translation elongation factor 1-α, calmodulin, RNA polymerase II second largest subunit, and Beta-tubulin (tub2) sequence data delimited two new species, namely F. khuzestanicum and F. oryzicola spp. nov., from previously known species of Fusarium within F. incarnatum-equiseti species complex (FIESC). Morphologically, F. khuzestanicum produces the macroconidia with distinctly notched to foot-shaped basal cells, while basal cells in the macroconidia of F. oryzicola are more extended and distinctly elongated foot shape. Furthermore, these two new species are distinguished by the size of their sporodochial phialides and macroconidia. The results of the present show that the FIESC species complex represent more cryptic species.
Asunto(s)
Fusarium , Oryza , Filogenia , Enfermedades de las Plantas , Fusarium/genética , Fusarium/clasificación , Fusarium/aislamiento & purificación , Irán , Oryza/microbiología , Enfermedades de las Plantas/microbiología , Tubulina (Proteína)/genética , Calmodulina/genética , ARN Polimerasa II/genética , Raíces de Plantas/microbiología , ADN de Hongos/genética , Factor 1 de Elongación Peptídica/genéticaRESUMEN
AIMS: Neocosmospora species are saprobes, endophytes, and pathogens belonging to the family Nectriaceae. This study aims to investigate the taxonomy, biosynthetic potential, and application of three newly isolated Neocosmospora species from mangrove habitats in the southern part of Thailand using phylogeny, bioactivity screening, genome sequencing, and bioinformatics analysis. METHODS AND RESULTS: Detailed descriptions, illustrations, and a multi-locus phylogenetic tree with large subunit ribosomal DNA (LSU), internal transcribed spacer (ITS), translation elongation factor 1-alpha (ef1-α), and RNA polymerase II second largest subunit (RPB2) regions showing the placement of three fungal strains, MFLUCC 17-0253, MFLUCC 17-0257, and MFLUCC 17-0259 clustered within the Neocosmospora clade with strong statistical support. Fungal crude extracts of the new species N. mangrovei MFLUCC 17-0253 exhibited strong antifungal activity to control Colletotrichum truncatum CG-0064, while N. ferruginea MFLUCC 17-0259 exhibited only moderate antifungal activity toward C. acutatum CC-0036. Thus, N. mangrovei MFLUCC 17-0253 was sequenced by Oxford nanopore technology. The bioinformatics analysis revealed that 49.17 Mb genome of this fungus harbors 41 potential biosynthetic gene clusters. CONCLUSION: Two fungal isolates of Neocosmospora and a new species of N. mangrovei were reported in this study. These fungal strains showed activity against pathogenic fungi causing anthracnose in chili. In addition, full genome sequencing and bioinformatics analysis of N. mangrovei MFLUCC 17-0253 were obtained.
Asunto(s)
Avicennia , Colletotrichum , Filogenia , Enfermedades de las Plantas , Antifúngicos/farmacología , Ascomicetos/genética , Agentes de Control Biológico , Colletotrichum/genética , ADN de Hongos/genética , Genoma Fúngico , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/prevención & control , Tailandia , Avicennia/microbiologíaRESUMEN
The genus Pseudogymnoascus represents a diverse group of fungi widely distributed in different cold regions on Earth. Our current knowledge of the species of Pseudogymnoascus is still very limited. Currently, there are only 15 accepted species of Pseudogymnoascus that have been isolated from different environments in the Northern Hemisphere. In contrast, species of Pseudogymnoascus from the Southern Hemisphere have not yet been described. In this work, we characterized four fungal strains obtained from Antarctic marine sponges. Based on multilocus phylogenetic analyses and morphological characterizations we determined that these strains are new species, for which the names Pseudogymnoascus antarcticus sp. nov., Pseudogymnoascus australis sp. nov., Pseudogymnoascus griseus sp. nov., and Pseudogymnoascus lanuginosus sp. nov. are proposed. Phylogenetic analyses indicate that the new species form distinct lineages separated from other species of Pseudogymnoascus with strong support. The new species do not form sexual structures and differ from the currently known species mainly in the shape and size of their conidia, the presence of chains of arthroconidia, and the appearance of their colonies. This is the first report of new species of Pseudogymnoascus not only from Antarctica but also from the Southern Hemisphere.
RESUMEN
The Nanfengmiju (Citrus reticulata cv. Nanfengmiju), a high-quality local variety of mandarin, is one of the major fruit crops in Jiangxi Province, China. Citrus melanose and stem-end rot, two common fungal diseases of Nanfengmiju, are both caused by Diaporthe spp. (syn. Phomopsis spp.). Identification of the Diaporthe species is essential for epidemiological studies, quarantine measures, and management of diseases caused by these fungi. Melanose disease was observed on Nanfengmiju fruit in Jiangxi Province of China in 2016. Based on morphological characterization and multi-locus phylogenetic analyses, three out of 39 isolates from diseased samples were identified as D. passifloricola. Since these three isolates did not cause melanose on citrus fruit in the pathogenicity tests, they were presumed to be endophytic fungi present in the diseased tissues. However, our results indicate that D. passifloricola may persist as a symptom-less endophyte in the peel of citrus fruit, yet it may cause stem-end if it invades the stem end during fruit storage. To the best of our knowledge, this is the first report of D. passifloricola as the causal agent of the stem-end rot disease in Citrus reticulata cv. Nanfengmiju.
RESUMEN
The ability of fungi isolated from nails of patients suffering from onychomycosis to induce de novo production of bioactive compounds in co-culture was examined. Comparison between the metabolite profiles produced by Sarocladium strictum, by Fusarium oxysporum, and by these two species in co-culture revealed de novo induction of fusaric acid based on HRMS. Structure confirmation of this toxin, using sensitive microflow NMR, required only three 9-cm Petri dishes of fungal culture. A targeted metabolomics study based on UHPLC-HRMS confirmed that the production of fusaric acid was strain-dependent. Furthermore, the detected toxin levels suggested that onychomycosis-associated fungal strains of the F. oxysporum and F. fujikuroi species complexes are much more frequently producing fusaric acid, and in higher amount, than strains of the F. solani species complex. Fusarium strains producing no significant amounts of this compound in pure culture, were shown to de novo produce that compound when grown in co-culture. The role of fusaric acid in fungal virulence and defense is discussed.