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Despite over a century of observations, the obligate insect parasites within the order Entomophthorales remain poorly characterized at the genetic level. In this manuscript, we present a genome for a laboratory-tractable Entomophthora muscae isolate that infects fruit flies. Our E. muscae assembly is 1.03 Gb, consists of 7810 contigs and contains 81.3% complete fungal BUSCOs. Using a comparative approach with recent datasets from entomophthoralean fungi, we show that giant genomes are the norm within Entomophthoraceae owing to extensive, but not recent, Ty3 retrotransposon activity. In addition, we find that E. muscae and its closest allies possess genes that are likely homologs to the blue-light sensor white-collar 1, a Neurospora crassa gene that has a well-established role in maintaining circadian rhythms. We uncover evidence that E. muscae diverged from other entomophthoralean fungi by expansion of existing families, rather than loss of particular domains, and possesses a potentially unique suite of secreted catabolic enzymes, consistent with E. muscae’s species-specific, biotrophic lifestyle. Finally, we offer a head-to-head comparison of morphological and molecular data for species within the E. muscae species complex that support the need for taxonomic revision within this group. Altogether, we provide a genetic and molecular foundation that we hope will provide a platform for the continued study of the unique biology of entomophthoralean fungi.

Symbiosis can facilitate the development of specialized organs in the host body to maintain relationships with beneficial microorganisms. To understand the developmental and genetic mechanisms by which such organs develop, it is critical to first investigate the morphology and developmental timing of these structures during the onset of host development. We utilized micro-computed tomography (μCT) to describe the morphology and development of mycangia, a specialized organ, in the Asian ambrosia beetle species Euwallacea validus which maintains a mutualistic relationship with the Ascomycete fungus, Fusarium oligoseptatum. We scanned animals in larval, pupal and adult life stages and identified that mycangia develop during the late pupal stage. Here we reconcile preliminary evidence and provide additional morphological data for a second paired set of structures, including the superior, medial mycangia and an inferior, lateral pair of pouch-like structures, in both late-stage pupae and adult female beetles. Furthermore, we report the possible development of rudimentary, or partially developed pairs of medial mycangia in adult male beetles which has never been reported for any male Xyleborini. Our results illustrate the validity of μCT in observing soft tissues and the complex nature of mycangia morphology and development.

The millipede fauna inhabiting deep soil are poorly known. They are small and threadlike, slow moving, lacking pigmentation, and rarely encountered due to their obscure underground way of life. One family, the Siphonorhinidae, encompasses four genera and 12 species in a fragmentary distribution in California, southern Africa, Madagascar, the Malay Archipelago, and Indo-Burma. The family is represented in the Western Hemisphere by a single genus, Illacme Cook & Loomis, 1928 from California, with its closest known relative, Nematozonium filum Verhoeff, 1939, from southern Africa. A new species of this family is documented from soil microhabitats in the Los Angeles metropolitan area, Illacme socal Marek & Shear, sp. nov. Based on this discovery and the recent documentation of other endogean millipede species, we show that these grossly understudied subterranean fauna represent the next frontier of discovery. However, they are threatened by encroaching human settlement and habitat loss, and conservation of this species and other subterranean fauna is of high importance.

Abstract Mutualistic interactions between organisms often mediate the innovation of traits essential to maintain the relationship. Yet our understanding of these interactions has been stymied due to various hurdles in studying the genetics of non-model animals. To understand the genetic mechanisms by which such traits develop, we examined the function of genes breathless (btl), trachealess (trh), and doublesex in the development of a novel fungus-carrying organ (mycangium) that facilitates an obligate relationship between fungus-farming ambrosia beetles and specific fungal partners. Gene knockdown by RNA interference and subsequent micro-computed tomography visualization suggest btl and trh are required for initiation of mycangia and that tubulogenesis may have been co-opted for early mycangial development.

Plant–pathogen interactions are often considered in a pairwise manner with minimal consideration of the impacts of the broader endophytic community on disease progression and/or outcomes for disease agents and hosts. Community interactions may be especially relevant in the context of disease complexes (i.e., interacting or functionally redundant causal agents) and decline diseases (where saprobes and weak pathogens synergize the effects of primary infections and hasten host mortality). Here we describe the bark endophyte communities associated with a widespread decline disease of American beech, beech bark disease (BBD), caused by an invasive scale insect (Cryptococcus fagisuga) and two fungal pathogens, Neonectria faginata and N. ditissima. We show that the two primary fungal disease agents co-occur more broadly than previously understood (35.5% of infected trees), including within the same 1-cm diameter phloem samples. The two species appear to have contrasting associations with climate and stages of tree decline, wherein N. faginata was associated with warmer and N. ditissima with cooler temperatures. Neonectria ditissima showed a positive association with tree crown dieback – no such association was observed for N. faginata. Further, we identify fungal endophytes that may modulate disease progression as entomopathogens, mycoparasites, saprotrophs, and/or additional pathogens, including Clonostachys rosea and Fusarium babinda. These fungi may alter the trajectory of disease via feedbacks with the primary disease agents or by altering symptom expression or rates of tree decline across the range of BBD.

Social media is an increasingly important professional tool for scientists. In particular, scientists use their social media profiles to communicate science and build communities with like-minded scientists and nonscientists. These networks include journalists who can amplify social media science communication, disseminating it to new audiences on- and offline. Our experience with an outreach project where Peeps marshmallows were inoculated with diverse fungi, which we called #FungalPeeps, has demonstrated that these networks can be an effective conduit between researchers and high school students. Following popular science journalism, #FungalPeeps, a project initiated at West Virginia University, inspired a mycology research project in Notre Dame High School in San Jose, California. Herein, we describe how this connection between academia, journalists, and the high school classroom happened, and how everyone involved benefited from this educational collaboration. We further suggest ways that modern social media networks could be leveraged to incorporate more such practical learning experiences into progressive science curricula to better cultivate young STEM scientists.