Biology subjects

Stajich, J. E.

Publications and source records attributed to Stajich, J. E..

72 records · Page 4Linked to original sources

bioRxiv2020

Genomic analyses of two Italian oyster mushroom Pleurotus pulmonarius strains

Pleurotus mushrooms are among the most cultivated fungi in the world and are highly valuable for food, medicine and biotechnology industries. Furthermore, Pleurotus species are carnivorous fungi; they can rapidly paralyze and kill nematodes when nutrient-deprived. The predator-prey interactions between Pleurotus and nematodes are still widely unexplored. Moreover, the molecular mechanisms and the genes involved in the carnivorous behavior of Pleurotus mushrooms remain a mystery. We are attempting to understand the interactions between Pleurotus mushrooms and their nematode prey through genetic and genomic analyses. Two single spores (ss2 and ss5) isolated from a fruiting body of Pleurotus pulmonarius exhibited significant differences in growth and toxicity against nematodes. Thus, using PacBio long reads, we assembled and annotated two high-quality genomes for these two isolates of Pleurotus pulmonarius. Each of these assemblies contains 23 scaffolds, including 6 (ss2) and 8 (ss5) telomere-to-telomere scaffolds, and they are among the most complete assembled genomes of the Pleurotus species. Comparative analyses identified the genomic differences between the two P. pulmonarius strains. In sum, this work provides a genomic resource that will be invaluable for better understanding the Italian oyster mushroom P. pulmonarius.

genomics↗

bioRxiv2020

A genome-scale phylogeny of Fungi; insights into early evolution, radiations, and the relationship between taxonomy and phylogeny

Phylogenomic studies based on genome-scale amounts of data have greatly improved understanding of the tree of life. Despite their diversity, ecological significance, and biomedical and industrial importance, large-scale phylogenomic studies of Fungi are lacking. Furthermore, several evolutionary relationships among major fungal lineages remain controversial, especially those at the base of the fungal phylogeny. To begin filling these gaps and assess progress toward a genome-scale phylogeny of the entire fungal kingdom, we compiled a phylogenomic data matrix of 290 genes from the genomes of 1,644 fungal species that includes representatives from most major fungal lineages; we also compiled 11 additional data matrices by subsampling genes or taxa based on filtering criteria previously shown to improve phylogenomic inference. Analyses of these 12 data matrices using concatenation- and coalescent-based approaches yielded a robust phylogeny of the kingdom in which [~]85% of internal branches were congruent across data matrices and approaches used. We found support for several relationships that have been historically contentious (e.g., for the placement of Wallemiomycotina (Basidiomycota), as sister to Agaricomycotina), as well as evidence for polytomies likely stemming from episodes of ancient diversification (e.g., at the base of Basidiomycota). By examining the relative evolutionary divergence of taxonomic groups of equivalent rank, we found that fungal taxonomy is broadly aligned with genome sequence divergence, but also identified lineages, such as the subphylum Saccharomycotina, where current taxonomic circumscription does not fully account for their high levels of evolutionary divergence. Our results provide a robust phylogenomic framework to explore the tempo and mode of fungal evolution and directions for future fungal phylogenetic and taxonomic studies.

evolutionary biology↗

bioRxiv2020

Genomic diversity generated by a transposable element burst in a rice recombinant inbred population

Genomes of all characterized higher eukaryotes harbor examples of transposable element (TE) bursts - the rapid amplification of TE copies throughout a genome. Despite their prevalence, understanding how bursts diversify genomes requires the characterization of actively transposing TEs before insertion sites and structural rearrangements have been obscured by selection acting over evolutionary time. In this study rice recombinant inbred lines (RILs), generated by crossing a bursting accession and the reference Nipponbare accession were exploited to characterize the spread of the very active Ping/mPing family through a small population and the resulting impact on genome diversity. Comparative sequence analysis of 272 individuals led to the identification of over 14,000 new insertions of the mPing miniature inverted-repeat transposable element (MITE) with no evidence for silencing of the transposase-encoding Ping element. In addition to new insertions, Ping-encoded transposase was found to preferentially catalyze the excision of mPing loci tightly linked to a second mPing insertion. Similarly, structural variations, including deletion of rice exons or regulatory regions, were enriched for those with breakpoints at one or both ends of linked mPing elements. Taken together, these results indicate that structural variations are generated during a TE burst as transposase catalyzes both the high copy numbers needed to distribute linked elements throughout the genome and the DNA cuts at the TE ends known to dramatically increase the frequency of recombination. Significance StatementTransposable elements (TEs) represent the largest component of the genomes of higher eukaryotes. Among this component are some TEs that have attained very high copy numbers with hundreds, even thousands of elements. By documenting the spread of mPing elements throughout the genomes of a rice population we demonstrate that such bursts of amplification generate functionally relevant genomic variations upon which selection can act. Specifically, continued mPing amplification increases the number of tightly linked elements that, in turn, increases the frequency of structural variations that appear to be derived from aberrant transposition events. The significance of this finding is that it provides a TE-mediated mechanism that may generate much of the structural variation represented by pan-genomes in plants and other organisms.

genetics↗

bioRxiv2020

Genomic insights into the host specific adaptation of the Pneumocystis genus and emergence of the human pathogen Pneumocystis jirovecii

Pneumocystis jirovecii, the fungal agent of human Pneumocystis pneumonia, is closely related to macaque Pneumocystis. Little is known about other Pneumocystis species in distantly related mammals, none of which are capable of establishing infection in humans. The molecular basis of host specificity in Pneumocystis remains unknown as experiments are limited due to an inability to culture any species in vitro. To explore Pneumocystis evolutionary adaptations, we have sequenced the genomes of species infecting macaques, rabbits, dogs and rats and compared them to available genomes of species infecting humans, mice and rats. Complete whole genome sequence data enables analysis and robust phylogeny, identification of important genetic features of the host adaptation, and estimation of speciation timing relative to the rise of their mammalian hosts. Our data reveals novel insights into the evolution of P. jirovecii, the sole member of the genus able to infect humans.

evolutionary biology↗

bioRxiv2020

Phylogenomic analyses of non-Dikarya fungi supports horizontal gene transfer driving diversification of secondary metabolism in the amphibian gastrointestinal symbiont, Basidiobolus

Research into secondary metabolism (SM) production by fungi has resulted in the discovery of diverse, biologically active compounds with significant medicinal applications. However, the fungi rich in SM production are taxonomically restricted to Dikarya, two phyla of Kingdom Fungi, Ascomycota and Basidiomycota. Here, we explore the potential for SM production in Mucoromycota and Zoopagomycota, two phyla of nonflagellated fungi that are not members of Dikarya, by predicting and identifying core genes and gene clusters involved in SM. The majority of non-Dikarya have few genes and gene clusters involved in SM production except for the amphibian gut symbionts in the genus Basidiobolus. Basidiobolus genomes exhibit an enrichment of SM genes involved in siderophore, surfactin-like, and terpene cyclase production, all these with evidence of constitutive gene expression. Gene expression and chemical assays confirm that Basidiobolus has significant siderophore activity. The expansion of SMs in Basidiobolus are partially due to horizontal gene transfer from bacteria, likely as a consequence of its ecology as an amphibian gut endosymbiont.

genomics↗

bioRxiv2020

Antarctic cryptoendolithic bacterial lineages of pre-Cambrian origin as proxy for Mars colonization

Cryptoendolithic communities are microbial ecosystems dwelling inside porous rocks. They are able to persist at the edge of the biological potential for life in the ice-free areas of continental Antarctica. These areas include the McMurdo Dry Valleys, often cited as a Terrestrial analog of the Martian environment. Despite their interest as a model for the early colonization by living organisms of terrestrial ecosystems and for adaptation to extreme conditions of stress, little is known about the evolution, diversity and genetic makeup of bacterial species that reside in these environments. We performed metagenomic sequencing of 18 communities from rocks collected in Antarctic desert areas over a distance of about 350 km. A total of 469 draft bacterial genome sequences were assembled, and clustered into 269 candidate species that lack a representative genome in public databases. The majority of these new species belong to monophyletic bacterial clades that diverged from related taxa in a range from 1.2 billion to 410 Ma, much earlier than the glaciation of Antarctica, and that are functionally distinct from known related taxa. The hypothesis that Antarctic cryptoendolithic bacterial lineages were generated by the selection of pre-existing cold-tolerant organisms whose origin dates back to the Tonian glaciations gives new insights for the possibility of life on Mars.

microbiology↗

bioRxiv2019

Shallow Genome Sequencing for Phylogenomics of Mycorrhizal Fungi from Endangered Orchids

Most plant species form symbioses with mycorrhizal fungi and this relationship is especially important for orchids. Fungi in the genera Tulasnella, Ceratobasidium, and Serendipita are critically important for orchid germination, growth and development. The goals of this study are to understand the phylogenetic relationships of mycorrhizal fungi and to improve the taxonomic resources for these groups. We identified 32 fungal isolates with the internal transcribed spacer region and used shallow genome sequencing to functionally annotate these isolates. We constructed phylogenetic trees from 408 orthologous nuclear genes for 50 taxa representing 14 genera, 11 families, and five orders in Agaricomycotina. While confirming relationships among the orders Cantharellales, Sebacinales, and Auriculariales, our results suggest novel relationships between families in the Cantharellales. Consistent with previous studies, we found the genera Ceratobasidium and Thanatephorus of Cerabotasidiaceae to not be monophyletic. Within the monophyletic genus Tulasnella, we found strong phylogenetic signals that suggest a potentially new species and a revision of current species boundaries (e.g. Tulasnella calospora); however it is premature to make taxonomic revisions without further sampling and morphological descriptions. There is low resolution of Serendipita isolates collected. More sampling is needed from areas around the world before making evolutionary-informed changes in taxonomy. Our study adds value to an important living collection of fungi isolated from endangered orchid species, but also informs future investigations of the evolution of orchid mycorrhizal fungi.

evolutionary biology↗

bioRxiv2019

Natural diversity in the predatory behavior facilitates the establishment of a new robust model strain for nematode-trapping fungi

Nematode-trapping fungi (NTF) are a group of specialized microbial predators that consume nematodes when food sources are limited. Predation is initiated when conserved nematode ascaroside pheromones are sensed, followed by the development of complex trapping devices. To gain insights into the co-evolution of this inter-kingdom predator-prey relationship, we investigated natural populations of nematodes and NTF, that we found to be ubiquitous in soils. Arthrobotrys species were sympatric with various nematode species and behaved as generalist predators. The ability to sense prey amongst wild isolates of A. oligospora varied greatly, as determined by the number of traps after exposure to Caenorhabditis elegans. While some strains were highly sensitive to C. elegans and the nematode pheromone ascarosides, others responded only weakly. Furthermore, strains that were highly sensitive to the nematode prey also developed traps faster. The polymorphic nature of trap formation correlated with competency in prey killing, as well as with the phylogeny of A. oligospora natural strains, calculated after assembly and annotation of the genomes of twenty isolates. A chromosome level genome assembly and annotation was established for one of the most sensitive wild isolate, and deletion of the only G protein {beta} subunit-encoding gene of A. oligospora nearly abolished trap formation, implicating G protein signaling in predation. In summary, our study establishes a highly responsive A. oligospora wild isolate as a novel model strain for the study of fungal-nematode interactions and demonstrates that trap formation is a fitness character in generalist predators of the NTF family. Significance statementNematode-trapping fungi (NTF) are carnivorous microbes that hold potential to be used as biological control agents due to their ability to consume nematodes. In this work we show that NTF are ubiquitous generalist predators found in sympatry with their prey in soil samples. Wild isolates of NTF displayed a naturally diverse ability to execute their predatory lifestyle. We generated a large whole genome sequencing dataset for many of the fungal isolates that will serve as the basis of future projects isolates. In particular, we establish TWF154, a highly responsive strain of Arthrobotrys oligospora, as a model strain to study the genetics of NTF. Lastly, we provide evidence that G-protein signaling is necessary for trap induction in NTF.

molecular biology↗

bioRxiv2019

Insights into the desert living skin microbiome: geography, soil depth, and crust type affect biocrust microbial communities and networks in Mojave Desert, USA

Biocrusts are the living skin of drylands, comprising diverse microbial communities that are essential to desert ecosystems. Although we have extensive knowledge on biocrust ecosystem function and what drives biodiversity in lichen and moss dominated biocrusts, much less is understood about the impacts of diversity among microbial communities. Moreover, most biocrust microbial composition studies have primarily focused on bacteria. We used amplicon-based metabarcode sequencing to explore composition of both fungal and bacterial communities in biocrusts. Specifically we tested how geography, soil depth, and crust type structured biocrust microbial communities or fungal-bacterial networks. Microbial communities were surveyed from biocrust surface and subsurface soils collected from Joshua Tree National Park, Granite Mountain, Kelso Dunes, and Cima volcanic flows located within the Mojave Desert, USA. Five biocrust types were examined: Light-algal, Cyano-lichen, Green-algal lichen, Smooth moss, and Rough moss crust types. We found the primary characteristics structuring biocrust microbial diversity were 1) geography, as central and southern Mojave sites displayed different community signatures, 2) presence of plant associated fungi (plant pathogens and wood saprotrophs), indicator, and endemic species were identified at each site, 3) soil depth patterns, as surface and subsurface microbial communities were distinctly structured, and 4) the crust type, which predicted distinct microbial compositions. Network analysis showed that Cyanobacteria and Dothideomycetes (Pleosporales) were the major hubs of overall biocrust microbial community. Such hierarchical spatial organization of biocrust communities and their associated biotic networks can have pronounced impacts to ecosystem functions. Our findings provide crucial insights for dryland restoration and sustainable management.

microbiology↗

bioRxiv2019

Evolutionary relationships among Massospora spp. (Entomophthorales), obligate pathogens of cicadas

The fungal genus Massospora (Zoopagomycota: Entomophthorales) includes more than a dozen obligate, sexually transmissible pathogenic species that infect cicadas (Hemiptera) worldwide. At least two species are known to produce psychoactive compounds during infection, which has garnered considerable interest for this enigmatic genus. As with many Entomophthorales, the evolutionary relationships and host associations of Massospora spp. are not well understood. The acquisition of M. diceroproctae from Arizona, M. tettigatis from Chile, and M. platypediae from California and Colorado provided an opportunity to conduct molecular phylogenetic analyses and morphological studies to investigate if these fungi represent a monophyletic group and delimit species boundaries. In a three-locus phylogenetic analysis including the D1-D2 domains of the nuclear 28S rRNA gene (28S), elongation factor 1 alpha-like (EFL), and beta-tubulin (BTUB), Massospora was resolved in a strongly supported monophyletic group containing four well-supported genealogically exclusive lineages, based on two of three methods of phylogenetic inference. There was incongruence among the single-gene trees: two methods of phylogenetic inference recovered trees with either the same topology as the 3-gene concatenated tree (EFL), or a basal polytomy (28S, BTUB). Massospora levispora and M. platypediae isolates formed a single lineage in all analyses and are synonymized here as M. levispora. Massospora diceroproctae was sister to M. cicadina in all three single-gene trees and on an extremely long branch relative to the other Massospora, and even the outgroup taxa, which may reflect an accelerated rate of molecular evolution and/or incomplete taxa sampling. The results of the morphological study presented here indicate that spore measurements may not be phylogenetically or diagnostically informative. Despite recent advances in understanding the ecology of Massospora, much about its host range and diversity remains unexplored. The emerging phylogenetic framework can provide a foundation for exploring co-evolutionary relationships with cicada hosts and the evolution of behavior-altering compounds.

microbiology↗

bioRxiv2019

Metagenomes in the borderline ecosystems of the Antarctic cryptoendolithic communities

Antarctic cryptoendolithic communities are microbial ecosystems dwelling inside rocks of ice-free areas in Continental Antarctica. In Antarctica, these ecosystems were first described from the McMurdo Dry Valleys, accounted as the best analogous of the Martian environment on Earth and thought to be devoid of life until the discovery of these cryptic life-forms. Our results present the first shotgun metagenomes of Antarctic cryptoendolithic lichen-dominated communities from 18 differently sun-exposed rock samples collected during the XXXI Italian Antarctic Expedition (2015-16), along an altitudinal transect from 834 up to 3100 m a.s.l. Here, we provide the raw data obtained with Illumina Novaseq sequencer, followed by initial functional and taxonomic analysis.\n\nOur results extend understanding of the microbial diversity and biological processes in the Antarctic desert and represent an invaluable resource for the scientific community as a base-line for further studies of this kind to examine the mechanisms and pathways necessary for life to adapt and evolve in the extremes.

microbiology↗

bioRxiv2019

Sampling strategies to assess microbial diversity of Antarctic cryptoendolithic communities.

Describing the total biodiversity of an environmental metacommunity is challenging due to the presence of cryptic and rare species and incompletely described taxonomy. How many samples to collect is a common issue faces ecologists when designing fieldwork sampling: collecting many samples may indeed capture the whole metacommunity structure, but can be prohibitively costly and lead to an enormous amount of data to analyse. Conversely, too few samples may yield inadequate and incomplete data which can prohibit complete assessment of community diversity. High-throughput sequencing allows examination of large numbers of samples enabling comprehensive biodiversity assessments. In this study, we sought to estimate how the scale of sampling affects accuracy of community diversity description in order to develop strategies to exhaustively describe the microbial diversity of cryptoendolithic communities in the McMurdo Dry Valleys in Antarctica accounted as the closest Martian analogue on Earth, exhibiting extreme conditions such as low temperatures, wide thermal fluctuations, low nutrient availability and high UV radiation. We found that sampling effort, based on accumulation curves analysis, had a considerable impact on assessing species richness and composition in these ecosystems, confirming that a sampling as large as nine rock specimens was necessary to detect almost all fungal species present, but was not sufficient to capture whole bacterial assemblage.

microbiology↗

bioRxiv2019

Sun exposure drives Antarctic cryptoendolithic community structure and composition.

The harsh environmental conditions of the ice-free regions of Continental Antarctica are considered one of the closest Martian analogues on Earth. There, rocks play a pivotal role as substratum for life and endolithism represents a primary habitat for microorganisms when external environmental conditions become incompatible with active life on rock surfaces. Due to the thermal inertia of rock, the internal airspace of lithic substratum is where microbiota find a protected and buffered microenvironment, allowing life to spread throughout these regions with extreme temperatures and low water availability. The high degree of adaptation and specialization of the endolithic communities makes them highly resistant but scarsely resilient to any external perturbation and thus, any shifts in microbial community composition may serve as early-alarm systems of environmental perturbation, including climate change.\n\nPrevious research concluded that altitude and distance from sea do not play as driving factors in shaping microbial abundance and diversity, while sun exposure was hypothesized as significant parameter influencing endolithic settlement and development. This study aims to explore our hypothesis that changes in sun exposure translate to shifts in community composition and abundances of main biological compartments (fungi, algae and bacteria) in the Antarctic cryptoendolithic communities. We performed a preliminary molecular survey, based on DGGE and qPCR tecniques, of 48 rocks with varying sun exposure, collected in Victoria Land along an altitudinal transect from 834 to 3100 m a.s.l.\n\nOur findings demonstrate that differences in sun radiation between north and south exposure influence temperature of rocks surface, availability of water and metabolic activity and also have significant impact on community composition and microbial abundance.

microbiology↗

bioRxiv2019

Diversity and function of fungi associated with the fungivorous millipede, Brachycybe lecontii

Fungivorous millipedes (subterclass Colobognatha) likely represent some of the earliest known mycophagous terrestrial arthropods, yet their fungal partners remain elusive. Here we describe relationships between fungi and the fungivorous millipede, Brachycybe lecontii. Their fungal community is surprisingly diverse with 176 genera, 39 orders, and four phyla and includes several undescribed species. Of particular interest are twelve genera conserved across wood substrates and millipede clades that comprise the core fungal community of B. lecontii. Wood decay fungi, long speculated to serve as the primary food source for Brachycybe species, were absent from this core assemblage and proved lethal to millipedes in pathogenicity assays while entomopathogenic Hypocreales were more common in the core but had little effect on millipede health. This study represents the first survey of fungal communities associated with any colobognath millipede, and these results offer a glimpse into the complexity of millipede fungal communities.

microbiology↗

bioRxiv2018

Horizontal gene transfer as an indispensible driver for Neocallimastigomycota evolution into a distinct gut-dwelling fungal lineage

Survival and growth of the anaerobic gut fungi (AGF, Neocallimastigomycota) in the herbivorous gut necessitate the possession of multiple abilities absent in other fungal lineages. We hypothesized that horizontal gene transfer (HGT) was instrumental in forging the evolution of AGF into a phylogenetically distinct gut-dwelling fungal lineage. Patterns of HGT were evaluated in the transcriptomes of 27 AGF strains, 22 of which were isolated and sequenced in this study, and 4 AGF genomes broadly covering the breadth of AGF diversity. We identified 283 distinct incidents of HGT in AGF transcriptomes, with subsequent gene duplication resulting in an HGT frequency of 2.1-3.6% in AGF genomes. The majority of HGT events were AGF specific (91.5%) and wide (70.7%), indicating their occurrence at early stages of AGF evolution. The acquired genes allowed AGF to expand their substrate utilization range, provided new venues for electron disposal, augmented their biosynthetic capabilities, and facilitated their adaptation to anaerobiosis. The majority of donors were anaerobic fermentative bacteria prevalent in the herbivorous gut. This work strongly indicates that HGT indispensably forged the evolution of AGF as a distinct fungal phylum and provides a unique example of the role of HGT in shaping the evolution of a high rank taxonomic eukaryotic lineage. ImportanceThe anaerobic gut fungi (AGF) represent a distinct basal phylum lineage (Neocallimastigomycota) commonly encountered in the rumen and alimentary tracts of herbivores. Survival and growth of anaerobic gut fungi in these anaerobic, eutrophic, and prokaryotes dominated habitats necessitates the acquisition of several traits absent in other fungal lineages. This manuscript assesses the role of horizontal gene transfer as a relatively fast mechanism for trait acquisition by the Neocallimastigomycota post sequestration in the herbivorous gut. Analysis of twenty-seven transcriptomes that represent the broad Neocallimastigomycota diversity identified 283 distinct HGT events, with subsequent gene duplication resulting in an HGT frequency of 2.1-3.6% in AGF genomes. These HGT events have allowed AGF to survive in the herbivorous gut by expanding their substrate utilization range, augmenting their biosynthetic pathway, providing new routes for electron disposal by expanding fermentative capacities, and facilitating their adaptation to anaerobiosis. HGT in the AGF is also shown to be mainly a cross-kingdom affair, with the majority of donors belonging to the bacteria. This work represents a unique example of the role of HGT in shaping the evolution of a high rank taxonomic eukaryotic lineage.

microbiology↗

bioRxiv2018

Comparative genomics and divergence time estimation of the anaerobic fungi in herbivorous mammals

The anaerobic gut fungi (AGF) or Neocallimastigomycota inhabit the rumen and alimentary tract of herbivorous mammals, where they play an important role in the degradation of plant fiber. Comparative genomic and phylogenomic analysis of the AGF has long been hampered by their fastidious growth pattern as well as their large and AT-biased genomes. We sequenced 21 AGF transcriptomes and combined them with 5 available genome sequences of AGF taxa to explore their evolutionary relationships, time their divergence, and characterize patterns of gene gain/loss associated with their evolution. We estimate that the most recent common ancestor of the AGF diverged 66 ({+/-}10) million years ago, a timeframe that coincides with the evolution of grasses (Poaceae), as well as the mammalian transition from insectivory to herbivory. The concordance of these independently estimated ages of AGF evolution, grasses evolution, and mammalian transition to herbivory suggest that AGF have been important in shaping the success of mammalian herbivory transition by improving the efficiency of energy acquisition from recalcitrant plant materials. Comparative genomics identified multiple lineage-specific genes and protein domains in the AGF, two of which were acquired from an animal host (galectin) and rumen gut bacteria (carbohydrate-binding domain) via horizontal gene transfer (HGT). Four of the bacterial derived "Cthe_2159" genes in AGF genomes also encode eukaryotic Pfam domains ("Atrophin-1", "eIF-3_zeta", "Nop14", and "TPH") indicating possible gene fusion events after the acquisition of "Cthe_2159" domain. A third AGF domain, plant-like polysaccharide lyase N-terminal domain ("Rhamnogal_lyase"), represents the first report from fungi that potentially aids AGF to degrade pectin. Analysis of genomic and transcriptomic sequences confirmed the presence and expression of these lineage-specific genes in nearly all AGF clades supporting the hypothesis that these laterally acquired and novel genes in fungi are likely functional. These genetic elements may contribute to the exceptional abilities of AGF to degrade plant biomass and enable metabolism of the rumen microbes and animal hosts.

evolutionary biology↗

bioRxiv2018

Discovery of psychoactive plant and mushroom alkaloids in ancient fungal cicada pathogens

Entomopathogenic fungi routinely kill their hosts before releasing infectious spores, but select species keep insects alive while sporulating, which enhances dispersal. Transcriptomics and metabolomics studies of entomopathogens with post-mortem dissemination from their parasitized hosts have unraveled infection processes and host responses, yet mechanisms underlying active spore transmission by Entomophthoralean fungi in living insects remain elusive. Here we report the discovery, through metabolomics, of the plant-associated amphetamine, cathinone, in four Massospora cicadina-infected periodical cicada populations, and the mushroom-associated tryptamine, psilocybin, in annual cicadas infected with Massospora platypediae or Massospora levispora, which appear to represent a single fungal species. The absence of some fungal enzymes necessary for cathinone and psilocybin biosynthesis along with the inability to detect intermediate metabolites or gene orthologs are consistent with possibly novel biosynthesis pathways in Massospora. The neurogenic activities of these compounds suggest the extended phenotype of Massospora that modifies cicada behavior to maximize dissemination is chemically-induced.

ecology↗

bioRxiv2018

Early diverging insect pathogenic fungi of the order Entomophthorales possess diverse and unique subtilisin-like serine proteases

Insect-pathogenic fungi use subtilisin-like serine proteases (SLSPs) to degrade chitin-associated proteins in the insect procuticle. Most insect-pathogenic fungi in the order Hypocreales (Ascomycota) are generalist species with a broad host-range, and most species possess a high number of SLSPs. The other major clade of insect-pathogenic fungi is part of the subphylum Entomophthoromycotina (Zoopagomycota, formerly Zygomycota) which consists of high host-specificity insect-pathogenic fungi that naturally only infect a single or very few host species. The extent to which insect-pathogenic fungi in the order Entomophthorales rely on SLSPs is unknown. Here we take advantage of recently available transcriptomic and genomic datasets from four genera within Entomophthoromycotina: the saprobic or opportunistic pathogens Basidiobolus meristosporus, Conidiobolus coronatus, C. thromboides, C. incongruus, and the host-specific insect pathogens Entomphthora muscae and Pandora formicae, specific pathogens of house flies (Muscae domestica) and wood ants (Formica polyctena), respectively. We use phylogenetics and protein domain analysis to show that the obligate biotrophic fungi E. muscae, P. formicae and the saprobic human pathogen C. incongruus all contain \"classical\" fungal SLSPs and a unique group of SLSPs that loosely resembles bacillopeptidase F-like SLSPs. This novel group of SLSPs is found in the genomes of obligate insect pathogens and a generalist saprobic opportunistic pathogen why they are unlikely to be responsible for the host specificity of Entomophthorales. However, this class represent a unique group of SLSPs so far only observed among Bacteria, Oomycetes and early diverging fungi such as Cryptomycota, Microsporidia, and Entomophthoromycotina and missing in the sister fungal lineages of Kickxellomycotina or the fungal phyla Mucoromyocta, Ascomycota and Basidiomycota fungi suggesting interesting gene loss patterns.

evolutionary biology↗