A multi-gene phylogeny for Stachybotrys evidences lack of trichodiene synthase (tri5) gene for isolates of one of three intrageneric lineages

Masters of the manipulator: two new hypocrealean genera, Niveomyces (Cordycipitaceae) and Torrubiellomyces (Ophiocordycipitaceae), parasitic on the zombie ant fungus Ophiocordyceps camponoti-floridani

During surveys in central Florida of the zombie-ant fungus Ophiocordyceps camponoti-floridani, which manipulates the behavior of the carpenter ant Camponotus floridanus, two distinct fungal morphotypes were discovered associated with and purportedly parasitic on O. camponoti-floridani. Based on a combination of unique morphology, ecology and phylogenetic placement, we discovered that these morphotypes comprise two novel lineages of fungi. Here, we propose two new genera, Niveomyces and Torrubiellomyces, each including a single species within the families Cordycipitaceae and Ophiocordycipitaceae, respectively. We generated de novo draft genomes for both new species and performed morphological and multi-loci phylogenetic analyses. The macromorphology and incidence of both new species, Niveomyces coronatus and Torrubiellomyces zombiae, suggest that these fungi are mycoparasites since their growth is observed exclusively on O. camponoti-floridani mycelium, stalks and ascomata, causing evident degradation of their fungal hosts. This work provides a starting point for more studies into fungal interactions between mycopathogens and entomopathogens, which have the potential to contribute towards efforts to battle the global rise of plant and animal mycoses. Citation: Araújo JPM, Lebert BM, Vermeulen S, et al. 2022. Masters of the manipulator: two new hypocrealean general, Niveomyces (Cordycipitaceae) and Torrubiellomyces (Ophiocordycipitaceae), parasitic on the zombie ant fungus Ophiocordyceps camponoti-floridani. Persoonia 49: 171-194. https://doi.org/10.3767/persoonia.2022.49.05.

Memnoniella sinensis sp. nov., a new species from China and a key to species of the genus

During a survey of fungal diversity in a deserted rocky area in Yunnan, PR China, a new species, Memnoniella sinensis, was identified. This new species is characterized by having phialidic conidiogenous cells with conspicuous collarettes, and aseptate, verrucose, ellipsoidal to sometimes ovoid, olivaceous brown to dark brown conidia. Morphologically, M. sinensis is similar to M. dichroa, but can be easily distinguished due to its hyaline conidiophores and smaller conidia. Phylogenetic analysis based on DNA sequences at five loci showed that our strain grouped together with M. dichroa and M. oenanthes. Here, the new species is described and illustrated, and a key to the species of the genus Memnoniella is provided.

Generic hyper-diversity in Stachybotriaceae

The family Stachybotriaceae was recently introduced to include the genera Myrothecium, Peethambara and Stachybotrys. Members of this family include important plant and human pathogens, as well as several species used in industrial and commercial applications as biodegraders and biocontrol agents. However, the generic boundaries in Stachybotriaceae are still poorly defined, as type material and sequence data are not readily available for taxonomic studies. To address this issue, we performed multi-locus phylogenetic analyses using partial gene sequences of the 28S large subunit (LSU), the internal transcribed spacer regions and intervening 5.8S nrRNA (ITS), the RNA polymerase II second largest subunit (rpb2), calmodulin (cmdA), translation elongation factor 1-alpha (tef1) and β-tubulin (tub2) for all available type and authentic strains. Supported by morphological characters these data resolved 33 genera in the Stachybotriaceae. These included the nine already established genera Albosynnema, Alfaria, Didymostilbe, Myrothecium, Parasarcopodium, Peethambara, Septomyrothecium, Stachybotrys and Xepicula. At the same time the generic names Melanopsamma, Memnoniella and Virgatospora were resurrected. Phylogenetic inference further showed that both the genera Myrothecium and Stachybotrys are polyphyletic resulting in the introduction of 13 new genera with myrothecium-like morphology and eight new genera with stachybotrys-like morphology.

MALDI-TOF mass spectrometry fingerprinting: A diagnostic tool to differentiate dematiaceous fungi Stachybotrys chartarum and Stachybotrys chlorohalonata

Stachybotrys chartarum and Stachybotrys chlorohalonata are two closely related species. Unambiguous identification of these two species is a challenging task if relying solely on morphological criteria and therefore smarter and less labor-intensive approaches are needed. Here we show that even such closely related species of fungi as S. chartarum and S. chlorohalonata are unequivocally discriminated by their highly reproducible MALDI-TOF-MS fingerprints (matrix assisted laser desorption/ionization time-of-flight mass spectrometry fingerprints). We examined 19 Stachybotrys and one Aspergillus isolate by MALDI-TOF-MS. All but one isolate produced melanin containing conidia on malt extract agar. Mass spectra were obtained in good quality from the analysis of hyaline and darkly pigmented conidia by circumventing the property of melanin which causes signal suppression. MALDI-TOF fingerprint analysis clearly discriminated not only the two morphologically similar species S. chartarum and S. chlorohalonata from each other but separated them precisely from Stachybotrys bisbyi and Aspergillus versicolor isolates. Furthermore, even S. chartarum chemotypes A and S could be differentiated into two distinct groups by their MALDI-TOF fingerprints. The chemotypes of S. chartarum isolates were identified by trichodiene synthase 5 (tri5) sequences prior to mass spectra analysis. Additionally, species identities of all isolates were verified by their 18S rRNA and tri5 gene sequences.

Stachybotrys eucylindrospora isolated from foreign material following a traumatic eye injury

Stachybotrys eucylindrospora was characterised as a new species in 2007, and we present the first report of this organism isolated from foreign material recovered from a patient. It is probable that isolates of this species have been previously identified as either Stachybotrys chartarum or Stachybotrys cylindrospora.

Identification of loci and functional characterization of trichothecene biosynthesis genes in filamentous fungi of the genus Trichoderma

Trichothecenes are mycotoxins produced by Trichoderma, Fusarium, and at least four other genera in the fungal order Hypocreales. Fusarium has a trichothecene biosynthetic gene (TRI) cluster that encodes transport and regulatory proteins as well as most enzymes required for the formation of the mycotoxins. However, little is known about trichothecene biosynthesis in the other genera. Here, we identify and characterize TRI gene orthologues (tri) in Trichoderma arundinaceum and Trichoderma brevicompactum. Our results indicate that both Trichoderma species have a tri cluster that consists of orthologues of seven genes present in the Fusarium TRI cluster. Organization of genes in the cluster is the same in the two Trichoderma species but differs from the organization in Fusarium. Sequence and functional analysis revealed that the gene (tri5) responsible for the first committed step in trichothecene biosynthesis is located outside the cluster in both Trichoderma species rather than inside the cluster as it is in Fusarium. Heterologous expression analysis revealed that two T. arundinaceum cluster genes (tri4 and tri11) differ in function from their Fusarium orthologues. The Tatri4-encoded enzyme catalyzes only three of the four oxygenation reactions catalyzed by the orthologous enzyme in Fusarium. The Tatri11-encoded enzyme catalyzes a completely different reaction (trichothecene C-4 hydroxylation) than the Fusarium orthologue (trichothecene C-15 hydroxylation). The results of this study indicate that although some characteristics of the tri/TRI cluster have been conserved during evolution of Trichoderma and Fusarium, the cluster has undergone marked changes, including gene loss and/or gain, gene rearrangement, and divergence of gene function.