The Symbiotic Spectrum: Where Do the Gregarines Fit?. Issue 9 (September 2019)

• Record Type: Journal Article
• Authors: Rueckert, Sonja; Betts, Emma L.; Tsaousis, Anastasios D.
• Is Part Of: Trends in parasitology. Volume 35:Issue 9(2019)
• Page Start: 687
• Page End: 694
• Publication Date: 2019-09
• Subjects: Apicomplexa -- gregarines -- symbiosis -- parasitism -- invertebrate microbiome; Parasitology -- Periodicals; Parasitology -- Periodicals; Biology -- Periodicals; Parasitology; Biology; Parasitologie -- Périodiques; Online resources; 571.999
• DOI: 10.1016/j.pt.2019.06.013
• Languages: English
• ISSNs: 1471-4922

Abstract

Abstract : Gregarine apicomplexans are closely related to parasites such as Plasmodium, Toxoplasma, and Cryptosporidium, which are causing severe health and economic burdens. Colonizing only invertebrates and having no obvious medical relevance, they are mostly ignored in 'omics' studies, although gregarines are the most basal apicomplexans and therefore key players in the understanding of the evolution of parasitism in the Apicomplexa from free-living ancestors. They belong to the largest exclusively parasitic phylum, but is this perception actually true? The effects of gregarines on their hosts seem to cover the whole spectrum of symbiosis from mutualistic to parasitic. We suggest future research directions to understand the evolutionary role of gregarines, by elucidating their biology and interaction with their hosts and the hosts' microbiota. Highlights: Parasites are generally considered to be harmful, but current debates and ongoing research showed that they can actually have beneficial effects on their hosts. Members of the Apicomplexa are unique microbial eukaryotes comprised entirely of symbiotic organisms, making it an ideal group to study the evolution of parasitism. Gregarines are highly diverse, residing in most invertebrates, but their pathogenicity and influence on their host's population ecology is still in question. Gregarines form the base of apicomplexan phylogenies. They are considered the most ancestral of the apicomplexans. The use of advanced methods to explore the gregarines' biology is still in its infancy. To elucidate the evolution of parasitism in the apicomplexans, a comprehensive understanding of the gregarines' biology, genetic make-up, host–parasite interactions and explorations of the hosts' holobiome is required.