This review examines the symbiotic, evolutionary, proteomic and genetic basis for a group of fungi that occupy a specialized niche as insect pathogens as well as endophytes. We focus primarily on species in the genera Metarhizium and Beauveria, traditionally recognized as insect pathogenic fungi but are also found as plant symbionts. Phylogenetic evidence suggests that these fungi are more closely related to grass endophytes and diverged from that lineage ca. 100 MYA. We explore how the dual life cycles of these fungi as insect pathogens and endophytes are coupled. We discuss the evolution of insect pathogenesis while maintaining an endophytic lifestyle and provide examples of genes that may be involved in the transition toward insect pathogenicity. That is, some genes for insect pathogenesis may have been co-opted from genes involved in endophytic colonization. Other genes may be multifunctional and serve in both lifestyle capacities. We suggest that their evolution as insect pathogens allowed them to effectively barter a specialized nitrogen source (i.e. insects) with host plants for photosynthate. These ubiquitous fungi may play an important role as plant growth promoters and have a potential reservoir of secondary metabolites.

Metarhizium robertsii is a common soil fungus that occupies a specialized ecological niche as an endophyte and an insect pathogen. Previously, we showed that the endophytic capability and insect pathogenicity of Metarhizium are coupled to provide an active method of insect-derived nitrogen transfer to a host plant via fungal mycelia. We speculated that in exchange for this insect-derived nitrogen, the plant would provide photosynthate to the fungus. By using 13CO2, we show the incorporation of 13C into photosynthate and the subsequent translocation of 13C into fungal-specific carbohydrates (trehalose and chitin) in the root/endophyte complex. We determined the amount of 13C present in root-associated fungal biomass over a 21-day period by extracting fungal carbohydrates and analysing their composition using nuclear magnetic resonance (NMR) spectroscopy. These findings are evidence that the host plant is providing photosynthate to the fungus, likely in exchange for insect-derived nitrogen in a tripartite, and symbiotic, interaction.

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Zika virus (ZIKV), belonging to the family Flaviviridae, genus Flavivirus, is an arthropod-borne virus that was first discovered from the Zika forest in Uganda in 1947. Recent outbreaks in South America have linked ZIKV to cases of microcephaly and Guillain-Barré syndrome in humans. With the increased interest in ZIKV, protocols must be established to facilitate proper research. Here we describe the laboratory techniques required to quantify, propagate, and store ZIVK. We also review the proper safety protocol for the handling of ZIKV, which is classified as a Biosafety Level 2 pathogen by the United States Centers for Disease Control and Prevention. © 2016 by John Wiley & Sons, Inc.

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Ceratopogonidae (Diptera) were collected on sheep farms in southern Ontario to establish whether Culicoides spp. pose a threat to the livestock industry. Specimens were collected in modified CO2-baited Centers for Disease Control and Prevention light traps, returned to the laboratory, freeze-killed, and identified to species under a microscope. In addition to Culicoides variipennis (Coquillet), we found that Culicoides sonorensis Wirth & Jones occurred on a number of farms over a 2-yr period. These records represent a significant departure from C. sonorensis' previously known geographical distribution. We present spatial and temporal distribution data for both species, with an emphasis on C. sonorensis. DNA sequence information is presented so that researchers lacking the necessary taxonomic skills can determine whether C. sonorensis is present in their collections. To differentiate C. sonorensis from C. variipennis, taxonomically reliable and informative traits were found in EF1α and, to a lesser extent, in ITS1, whereas the universal barcode region of cytochrome oxidase subunit 1 (CO1) was unsuitable.

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Insect pathogenic fungi such as Metarhizium anisopliae and Beauveria bassiana have an increasing role in the control of agricultural insect pests and vectors of human diseases. Many of the virulence factors are well studied but less is known of the metabolism of these fungi during the course of insect infection or saprobic growth. Here, we assessed enzyme activity and gene expression in the central carbon metabolic pathway, including isocitrate dehydrogenase, aconitase, citrate synthase, malate synthase (MLS) and isocitrate lyase (ICL), with particular attention to the glyoxylate cycle when M. anisopliae and B. bassiana were grown under various conditions. We observed that ICL and MLS, glyoxylate cycle intermediates, were upregulated during growth on 2-carbon compounds (acetate and ethanol) as well as in insect haemolymph. We fused the promoter of the M. anisopliae ICL gene (Ma-icl) to a marker gene (mCherry) and showed that Ma-icl was upregulated when M. anisopliae was grown in the presence of acetate. Furthermore, Ma-icl was upregulated when fungi were engulfed by insect haemocytes as well as during appressorium formation. Addition of the ICL inhibitor 3-nitroproprionate delayed conidial germination and inhibited appressorium formation. These results show that these insect pathogenic fungi have a flexible metabolism that includes the glyoxylate cycle as an integral part of germination, pathogenesis and saprobic growth.