Advancing Endosymbiotic Microbial Research by Targeting Early Diverging Fungi in the Digestive Tracts of Arthropods

Trichomycetes is an ecological group of endosymbiotic gut fungi found worldwide in non-predaceous terrestrial and aquatic arthropods. Some genera of one order, Harpellales, have been isolated in axenic culture, whereas species of Asellariales (harbored by isopods and springtails) have so far remained “unculturable”. This research project sought to obtain some of these fungi with local collections of candidate hosts during the summer of 2018. Aquatic and terrestrial isopods were collected from numerous field sites and typically dissected within one to four days. Fungi harvested from the digestive tracts were examined with the aid of a stereo microscope to confirm presence of endosymbionts. Gut dissections with robust thalli production were used for culture attempts with various experimental media combinations; including different media and growth conditions such as percentage of agar, pH, fluid overlay, and incubation temperature. Pure cultures are fundamental for the advancement of our understanding of microbial life and, in parallel with projects such as Zygolife, will allow integral studies to be performed. These endosymbiotic organisms can range from parasitic to mutualistic, and may well have biochemical pathways that are novel and specific to Trichomycetes, but nonetheless attractive from a number of human perspectives