Exploring the Role of Macroalgal Surface Metabolites on the Settlement of the Benthic Dinoflagellate Ostreopsis cf. ovata

Abstract

Macroalgae constitute one of the preferred substrates of the benthic dinoflagellate Ostreopsis cf. ovata. Across the Mediterranean Sea, this toxic microalga has been shown to thrive on the surface of various species of macroalgae, including Chlorophyta, Rhodophyta, and Phaeophyceae. Interestingly, some Dictyotaceae are characterized by a low abundance of cells of O. cf. ovata on their surface. Based on the antifouling properties of some specialized metabolites produced by seaweeds, macroalgal metabolites have been proposed to contribute to the settlement and development of O. cf. ovata. To address this question, the composition of the surface of four Dictyotaceae, Dictyota dichotoma, Dictyota spiralis, Taonia atomaria, and Padina pavonica was investigated through an integrative approach combining the analysis of their eukaryotic diversity (18S rRNA gene metabarcoding), their surface metabolome (untargeted LC-MS-based metabolomics) as well as the bioactivity of their surface extracts on O. cf. ovata. Altogether, the data suggest an influence of the macroalgal surface chemistry on the growth of the dinoflagellate, with D. dichotoma being the most bioactive. Some metabolites are proposed to be involved in the observed bioactivity. Other biotic factors are also likely to be entailed in the control of the O. cf. ovata population and they may even prevail on the influence of the macroalgal surface chemistry.

Synergistic effects of temperature and light affect the relationship between Taonia atomaria and its epibacterial community: a controlled conditions study

“…Taken together, these results may strengthen the hypothesis of a light-dependent DMSP biosynthesis, especially in the case of lowtemperature conditions (Karsten et al, 1992). Moreover, DMSP is also produced by many microalgae, including dinoflagellates and diatoms (Bullock et al, 2017), and the potential origin of DMSP at the surface of T. atomaria could also be linked to such epiphytes that were identified on several Dictyotaceae including T. atomaria (Ternon et al, 2020). Besides, DMSP constitutes a source of carbon and sulfur for a large diversity of bacteria, especially those from the Roseobacter clade (Howard et al, 2008;Curson et al, 2011;Dogs et al, 2017).…”

“…atomaria could also be linked to such epiphytes that were identified on several Dictyotaceae including T . atomaria (Ternon et al ., 2020). Besides, DMSP constitutes a source of carbon and sulfur for a large diversity of bacteria, especially those from the Roseobacter clade (Howard et al ., 2008; Curson et al ., 2011; Dogs et al ., 2017).…”

The role of habitat in the facilitation of Ostreopsis spp. blooms

“…However, the substrate preferences of Ostreopsis spp. are still ambiguous (Vila et al, 2001;Cohu et al, 2013;Sparrow et al, 2017;Ternon et al, 2020;Tester et al, 2020), although some studies reported larger abundances on some substrates compared to others (Vila et al, 2001(Vila et al, , 2012Mohammad-Noor et al, 2007;Widiarti, 2008;Cabrini et al, 2010;Totti et al, 2010;Accoroni et al, 2011Accoroni et al, , 2012Accoroni and Totti, 2016;Yong et al, 2018;Boisnoir et al, 2019;Bravo et al, 2020;Lee et al, 2020). Such comparisons are tricky because of the limits of cell quantification in function of the type of substrate (i.e.…”

“…(Aligizaki and Nikolaidis, 2006;Monti et al, 2007;Okolodkov et al, 2007;Totti et al, 2010 ;Ismael and Halim, 2012), Dictyota spp. (Cohu et al, 2013 ;Blanfune et al, 2015;González et al, 2019;Gémin et al, 2020 ;Ternon et al, 2020), and Cystoseira sensu lato spp. (Aligizaki and Nikolaidis, 2006;Monti et al, 2007;Aligizaki and Nikolaidis, 2008;Blanfune et al, 2015;Catania, 2017;Moncer et al, 2017;Meroni et al, 2018).…”

“…(Aligizaki and Nikolaidis, 2006;Monti et al, 2007;Aligizaki and Nikolaidis, 2008;Blanfune et al, 2015;Catania, 2017;Moncer et al, 2017;Meroni et al, 2018). Ostreopsis abundances on different substrates are highly variable and, despite the technical issues linked to the measurement cited above, several biotic factors acting at different spatial scales can be responsible for such variability: morphology and palatability of macrophytes, herbivory and allelopathic interactions due to the production of secondary metabolites by living substrates, among others (Cruz-Rivera and Villareal, 2006;Totti et al, 2010;Accoroni et al, 2015;Ternon et al, 2020).…”