[Seminar] "Endosymbiotic Apicomplexans of Marine Holobionts: bridging ecology & evolution" by Dr. Anthony Bonacolta

Speaker: Dr. Anthony M. Bonacolta, Postdoctoral Research Fellow, The University of British Columbia [The Keeling Lab][Google Scholar]

Title: Endosymbiotic Apicomplexans of Marine Holobionts: bridging ecology & evolution

Abstract: 

Apicomplexans are a large group of parasitic alveolates that cause devastating human diseases such as malaria. They are obligate intracellular parasites that have an interesting evolutionary history, having evolved from a free-living, phototrophic ancestor. Despite the extensive research interest in this group, new apicomplexans with significant ecological roles are still being discovered. My work focuses on three new lineages of endosymbiotic apicomplexans described in the last decade: the corallicolids, ichthyocolids, and apostichocystids. Corallicolids, previously known as ARL-V or Type-N in metabarcoding surveys, are found as symbionts in 70% of surveyed anthozoans from tropical shallow coral reefs to deep, cold water benthic habitats. My research has revealed their potential role in coral thermal tolerance and has expanded their known host range to fireworms, providing key insights into their cryptic ecology. The ichthyocolids, previously ARL-VI, are blood parasites of fish that were misclassified as hemogregarines before we conducted a phylogenomic investigation showing this clade to be sister to the corallicolids and widespread across sampled fish diversity. Lastly, my colleagues and I have described Apostichocystis gudetama, a coccidian infecting the ovaries of female Japanese sea cucumbers. Using an expanded phylogenetic framework, we have shown this species to be closely related to both the corallicolids and ichthyocolids. The unique divergence and evolutionary trajectory of each of these marine-host associated lineages provides key insights into parasite evolution and symbiosis in the ocean.