Red algal parasites: A synopsis of described species, their hosts, distinguishing characters and areas for continued research

Abstract

© 2017 Walter de Gruyter GmbH, Berlin/Boston. Red algal parasites are diverse organisms that are unusual due to the fact that many are closely related to their hosts. Parasitism has developed many times within different red algal groups, but the full extent of parasite biodiversity is unknown, as parasites are easily overlooked due to their small size and often low abundance. Additionally, the literature on red algal parasites is dispersed and has not been compiled in over 30 years. Although criteria have been proposed to define what constitutes a red algal parasite, many parasites are poorly described, and the cellular interactions with their host are poorly known. A few studies have demonstrated that parasites transfer organelles to host cells, which can alter the physiology of the host to the benefit of the parasite. Here, we apply a set of defining criteria for parasites to a compiled list of all described red algal parasites. Our results highlight the lack of knowledge of many key parasitic processes including early parasite development, host cell "control", and parasite origin. Until the biology of more parasites is studied, generalisations on the processes of parasitism in red algae may be premature. We hope this synopsis will stimulate research into this fascinating group.

<p><strong>Transfer of the marine red alga <em>Erythrocystis saccata</em> (Rhodomelaceae, Rhodophyta) to the tribe Streblocladieae inferred from organellar genome analysis</strong></p>

“…Silva (1952: 308) from the Atlantic Islands and the Mediterranean Sea (Abbott & Hollenberg 1976, Guiry & Guiry 2021. Erythrocystis has been considered parasitic, hemiparasitic, symbiotic, or epiphytic (Kylin 1928, Kugrens & West 1974, Melchionna & De Masi 1977, Preuss et al 2017. Based on observations of the vegetative and reproductive development, Kylin (1928) assigned Erythrocystis (as Ricardia) to the tribe Laurencieae, stating that it joined the tribe "sehr gut an" (very good).…”