TY - JOUR T1 - Multiple microalgal partners in symbiosis with the acantharian Acanthochiasma sp. (Radiolaria) A1 - Decelle,Johan A1 - Siano,Raffaele A1 - Probert,Ian A1 - Poirier,C A1 - Not,Fabrice AD - Univ Paris 06, UMR 7144, Biol Stn, F-29680 Roscoff, France. AD - CNRS, Biol Stn, UMR 7144, F-29680 Roscoff, France. AD - IFREMER, Ctr Brest, DYNECO Pelagos, F-29280 Plouzane, France. AD - Univ Paris 06, FR 2424, Biol Stn, F-29680 Roscoff, France. UR - https://doi.org/10.1007/s13199-012-0195-x DO - 10.1007/s13199-012-0195-x KW - Photosymbiosis KW - Radiolaria KW - Acantharia KW - Protists KW - Microalgae KW - Plankton N2 - Acantharia (Radiolaria) are widespread and abundant heterotrophic marine protists, some of which can host endosymbiotic eukaryotic microalgae. Although this photosymbiotic association was first described at the end of the 19th century, the diversity of the symbiotic microalgae remains poorly characterized. Here, we examined the identity of the microalgae associated with the acantharian species Acanthochiasma sp. by sequencing partial 18S and internal transcribed spacer (ITS) ribosomal DNA genes from cultured symbionts and directly from isolated holobiont specimens. Single Acanthochiasma cells contained multiple symbiotic partners, including distantly related dinoflagellates (Heterocapsa sp., Pelagodinium sp., Azadinium sp. and Scrippsiella sp.) as well as a haptophyte (Chrysochromulina sp.). This original association of multiple symbiotic microalgae within a single host cell raises questions about the specificity and functioning of the relationship. These microalgae exhibit the common ecological feature of being abundant and widely distributed in coastal and oceanic waters, some occasionally forming extensive blooms. Some of the microalgal genera found in association with Acanthochiasma (i.e. Pelagodinium and Chrysochromulina) are known to occur in symbiosis with other heterotrophic protists such as Foraminifera and other Radiolaria, whereas Heterocapsa, Scrippsiella and Azadinium have never previously been reported to be involved in putative symbiotic relationships. The unusual association unveiled in this study contributes to our understanding of the ecological and evolutionary significance of photosymbiosis in Acantharia and also provides new insights into the nature of such partnerships in the planktonic realm. Y1 - 2012/12 PB - Springer JF - Symbiosis SN - 0334-5114 VL - 58 IS - 1-3 SP - 233 EP - 244 ID - 22493 ER -