Persoonia最新文献

Over the past few years, symptoms akin to late blight disease have been reported on a variety of crop plants in South America. Despite the economic importance of these crops, the causal agents of the diseases belonging to the genus Phytophthora have not been completely characterized. In this study, a new Phytophthora species was described in Colombia from tree tomato (Solanum betaceum), a semi-domesticated fruit grown in northern South America. Comprehensive phylogenetic, morphological, population genetic analyses, and infection assays to characterize this new species, were conducted. All data support the description of the new species, Phytophthora betacei sp. nov. Phylogenetic analyses suggest that this new species belongs to clade 1c of the genus Phytophthora and is a close relative of the potato late blight pathogen, P. infestans. Furthermore, it appeared as the sister group of the P. andina strains collected from wild Solanaceae (clonal lineage EC-2). Analyses of morphological and physiological characters as well as host specificity showed high support for the differentiation of these species. Based on these results, a complete description of the new species is provided and the species boundaries within Phytophthora clade 1c in northern South America are discussed.

Malassezia is a genus of medically-important, lipid-dependent yeasts that live on the skin of warm-blooded animals. The 17 described species have been documented primarily on humans and domestic animals, but few studies have examined Malassezia species associated with more diverse host groups such as wildlife. While investigating the skin mycobiota of healthy bats, we isolated a Malassezia sp. that exhibited only up to 92% identity with other known species in the genus for the portion of the DNA sequence of the internal transcribed spacer region that could be confidently aligned. The Malassezia sp. was cultured from the skin of nine species of bats in the subfamily Myotinae; isolates originated from bats sampled in both the eastern and western United States. Physiological features and molecular characterisation at seven additional loci (D1/D2 region of 26S rDNA, 18S rDNA, chitin synthase, second largest subunit of RNA polymerase II, β-tubulin, translation elongation factor EF-1α, and minichromosome maintenance complex component 7) indicated that all of the bat Malassezia isolates likely represented a single species distinct from other named taxa. Of particular note was the ability of the Malassezia sp. to grow over a broad range of temperatures (7-40 °C), with optimal growth occurring at 24 °C. These thermal growth ranges, unique among the described Malassezia, may be an adaptation by the fungus to survive on bats during both the host's hibernation and active seasons. The combination of genetic and physiological differences provided compelling evidence that this lipid-dependent yeast represents a novel species described herein as Malassezia vespertilionis sp. nov. Whole genome sequencing placed the new species as a basal member of the clade containing the species M. furfur, M. japonica, M. obtusa, and M. yamatoensis. The genetic and physiological uniqueness of Malassezia vespertilionis among its closest relatives may make it important in future research to better understand the evolution, life history, and pathogenicity of the Malassezia yeasts.

Exserohilum includes a number of plant pathogenic, saprobic and clinically relevant fungi. Some of these species are of great importance in human activities, but the genus has never been revised in a phylogenetic framework. In this study, we revise Exserohilum based on available ex-type cultures from worldwide collections, observation of the holotypes and/or protologues, and additional isolates from diverse substrates and geographical origins. Based on nine nuclear loci, i.e., ITS, LSU, act, tub2, cam, gapdh, his, tef1 and rpb2, as well as phenotypic data, the genus and species boundaries are assessed for Exserohilum. Three species, i.e., E. novae-zelandiae, E. paspali and E. sorghicola, are excluded from the genus and reallocated in Sporidesmiella and Curvularia, respectively, whereas E. heteropogonicola and E. inaequale are confirmed as members of Curvularia. Exserohilum rostratum is revealed as conspecific with species previously described in Exserohilum such as E. antillanum, E. gedarefense, E. leptochloae, E. longirostratum, E. macginnisii and E. prolatum. Additionally, E. curvatum is revealed as synonym of E. holmii, and E. fusiforme of E. oryzicola. A total of 11 Exserohilum phylogenetic species are described, illustrated and discussed, including one novel taxon, E. corniculatum. The placements of 15 other doubtful species are discussed, and E. elongatum is validated.

Junghuhnia is a genus of polypores traditionally characterised by a dimitic hyphal system with clamped generative hyphae and presence of encrusted skeletocystidia. However, recent molecular studies revealed that Junghuhnia is polyphyletic and most of the species cluster with Steccherinum, a morphologically similar genus separated only by a hydnoid hymenophore. In the Neotropics, very little is known about the evolutionary relationships of Junghuhnia s.lat. taxa and very few species have been included in molecular studies. In order to test the proper phylogenetic placement of Neotropical species of this group, morphological and molecular analyses were carried out. Specimens were collected in Brazil and used for DNA sequence analyses of the internal transcribed spacer and the large subunit of the nuclear ribosomal RNA gene, the translation elongation factor 1-α gene, and the second largest subunit of RNA polymerase II gene. Herbarium collections, including type specimens, were studied for morphological comparison and to confirm the identity of collections. The molecular data obtained revealed that the studied species are placed in three different genera. Specimens of Junghuhnia carneola represent two distinct species that group in a lineage within the phlebioid clade, separated from Junghuhnia and Steccherinum, which belong to the residual polyporoid clade. Therefore, the new genus Geesterania is proposed including two species, G. carneola comb. nov. and G. davidii sp. nov. Neotropical specimens identified as Junghuhnia nitida represent a different lineage from the European species and are described as Steccherinum neonitidum sp. nov. In addition, the new combinations Steccherinum meridionale, Steccherinum polycystidiferum and Steccherinum undigerum, as well as the new name Flaviporus tenuis, are proposed.

Species of Diaporthe are considered important plant pathogens, saprobes, and endophytes on a wide range of plant hosts. Several species are well-known on grapevines, either as agents of pre- or post-harvest infections, including Phomopsis cane and leaf spot, cane bleaching, swelling arm and trunk cankers. In this study we explore the occurrence, diversity and pathogenicity of Diaporthe spp. associated with Vitis vinifera in major grape production areas of Europe and Israel, focusing on nurseries and vineyards. Surveys were conducted in Croatia, Czech Republic, France, Hungary, Israel, Italy, Spain and the UK. A total of 175 Diaporthe strains were isolated from asymptomatic and symptomatic shoots, branches and trunks. A multi-locus phylogeny was established based on five genomic loci (ITS, tef1, cal, his3 and tub2), and the morphological characters of the isolates were determined. Preliminary pathogenicity tests were performed on green grapevine shoots with representative isolates. The most commonly isolated species were D. eres and D. ampelina. Four new Diaporthe species described here as D. bohemiae, D. celeris, D. hispaniae and D. hungariae were found associated with affected vines. Pathogenicity tests revealed D. baccae, D. celeris, D. hispaniae and D. hungariae as pathogens of grapevines. No symptoms were caused by D. bohemiae. This study represents the first report of D. ambigua and D. baccae on grapevines in Europe. The present study improves our understanding of the species associated with several disease symptoms on V. vinifera plants, and provides useful information for effective disease management.

Most members of the oomycete genus Phytophthora are primary plant pathogens. Both soil- and airborne Phytophthora species are able to survive adverse environmental conditions with enduring resting structures, mainly sexual oospores, vegetative chlamydospores and hyphal aggregations. Soilborne Phytophthora species infect fine roots and the bark of suberized roots and the collar region with motile biflagellate zoospores released from sporangia during wet soil conditions. Airborne Phytophthora species infect leaves, shoots, fruits and bark of branches and stems with caducous sporangia produced during humid conditions on infected plant tissues and dispersed by rain and wind splash. During the past six decades, the number of previously unknown Phytophthora declines and diebacks of natural and semi-natural forests and woodlands has increased exponentially, and the vast majority of them are driven by introduced invasive Phytophthora species. Nurseries in Europe, North America and Australia show high infestation rates with a wide range of mostly exotic Phytophthora species. Planting of infested nursery stock has proven to be the main pathway of Phytophthora species between and within continents. This review provides insights into the history, distribution, aetiology, symptomatology, dynamics and impact of the most important canker, decline and dieback diseases caused by soil- and airborne Phytophthora species in forests and natural ecosystems of Europe, Australia and the Americas.

The diversity of fusaria in symptomatic Citrus trees in Greece, Italy and Spain was evaluated using morphological and molecular multi-locus analyses based on fragments of the calmodulin (CAM), intergenic spacer region of the rDNA (IGS), internal transcribed spacer region of the rDNA (ITS), large subunit of the rDNA (LSU), RNA polymerase largest subunit (RPB1), RNA polymerase second largest subunit (RPB2), translation elongation factor 1-alpha (EF-1α) and beta-tubulin (TUB) genes. A total of 11 species (six Fusarium spp., and five Neocosmospora spp.) were isolated from dry root rot, crown, trunk or twig canker or twig dieback of citrus trees. The most commonly isolated species were Fusarium sarcochroum, F. oxysporum and Neocosmospora solani. Three new Fusarium species are described, i.e., F. citricola and F. salinense belonging to the newly described F. citricola species complex; and F. siculi belonging to the F. fujikuroi species complex. Results of pathogenicity tests showed this new complex to include prominent canker causing agents affecting several Citrus spp. In addition, two new species are described in Neocosmospora, named N. croci and N. macrospora, the latter species being clearly differentiated from most members of this genus by producing large, up to nine-septate sporodochial conidia.

Inocybe mixtilis constitutes a complex of species characterized by nodulose-angulose spores, absence of cortina and a more or less bulbous marginate stipe that is not darkening when desiccated. In order to elucidate species limits within the I. mixtilis complex, an ITS-RPB2 phylogeny was performed and interpreted using morphological and ecological characters. Six supported clades were obtained in our analyses that correspond to I. mixtilis, I. subtrivialis, and four new species to science: I. ceskae, I. johannis-stanglii, I. nothomixtilis and I. occulta. Species within this complex can be morphologically recognized through a unique combination of morphological characters, such as the spore shape, cystidial length and shape, presence and development of the velipellis and pileus colour and viscidity. Nevertheless, those characters overlap, especially among I. mixtilis, I. ceskae and I. occulta, and intermediate collections are therefore more reliably identified through ITS-sequencing. Two species, I. ceskae and I. occulta are present in both North America and Europe, while the rest are so far only known in Europe, or Europe and Asia (I. mixtilis). All species, except I. johannis-stanglii, seem to be able to establish ectomycorrhizal association both with conifers and angiosperms. Descriptions, colour illustrations and a key to all known species in the I. mixtilis group are provided.

The genus Neocosmospora encompasses highly prevalent and aggressive human and animal fungal pathogens. Here we assign formal descriptions and Latin binomials to some of the most clinically relevant phylogenetic species of the genus. Three new species, named Neocosmospora catenata, N. gamsii and N. suttoniana (previously assigned to the informal names 'Fusarium' solani species complex (FSSC) lineages, FSSC 43, FSSC 7 and FSSC 20, respectively) are described on the basis of multilocus phylogenetic analyses (using EF-1α, ITS, LSU and RPB2 loci) and morphological characters. Lineage FSSC 9 is conspecific with the ex-type strain of Cylindrocarpon tonkinense, thus the new combination Neocosmospora tonkinensis is proposed. In addition, and based on the latest taxonomy for this generic complex, new combinations are introduced for four medically important taxa: Neocosmospora keratoplastica, N. lichenicola, N. metavorans and N. petroliphila. The most significant distinctive features for all the clinically relevant species treated here are compared and illustrated.

Four new species of Hohenbuehelia (Fungi: Pleurotaceae) are described in the group of Hohenbuehelia atrocoerulea and Hohenbuehelia grisea. Hohenbuehelia algonquinensis, found on Pinus in Ontario, Canada, may be distinguished macroscopically from bluish collections of H. atrocoerulea and watery grey-brown collections of H. grisea by its coal-black pileus. Hohenbuehelia canadensis, on or associated with Pinus in both Ontario and Alberta, Canada, and Hohenbuehelia nimueae, on Salix in Ontario and Abies in Wyoming, USA, have similarly dark fruiting bodies and were previously misidentified as H. approximans (which we treat as a synonym of H. grisea), H. atrocoerulea, H. mustialensis or H. nigra. The latter species is shown to be a member of Resupinatus, despite the presence of prominent metuloid cystidia in its hymenium. Hohenbuehelia carlothornii has been found in Costa Rica; collections of the sexual fruiting bodies were previously identified as H. grisea and isolates from soil nematodes were identified by the anamorph name Nematoctonus robustus. That name has been treated as a synonym of H. atrocoerulea but, given the genetic and geographic variation within this complex, we transfer it to Hohenbuehelia as a distinct species. Sequences of the nuclear ribosomal DNA internal transcribed spacer region (ITS), the D1/D2 variable region of the large subunit gene, and a portion of the translation elongation factor (TEF1) gene provide good separation and support for these new species. A key to the dimidiate species of Hohenbuehelia of North America and Europe is provided.