Phylogenetic evidence for multiple independent origins of functional kleptoplasty in Sacoglossa (Heterobranchia, Gastropoda)

Abstract

Sacoglossa is a rather small taxon of marine slugs with about 300 described species, yet it is quite fascinating scientists for decades. This is mainly because of the ability of certain species to incorporate photosynthetically active plastids of their algae prey, a phenomenon known as functional kleptoplasty. With the stolen plastids, these slugs endure weeks (short-term retention) or months (long-term retention) of starvation, though contribution of the plastids to the survival and factors enhancing plastid longevity are unknown. Likewise, contrasting hypotheses on evolution of functional kleptoplasty exist and the phylogenetic relationship of Sacoglossa taxa is still under debate. We analyzed the phylogenetic relationship of 105 sacoglossan species to address the question of the origin of functional kleptoplasty. Based on our phylogenetic analysis and the ancestral character state reconstruction, we conclude that functional short-term retention most likely originated two times and long-term retention at least five times. Previous suggestions that functional longterm kleptoplasty is established with specific plastids are supported by our food analyses in Elysia clarki that finally harbors only plastids of certain algae species over a prolonged starvation period.

Photoprotective Non-photochemical Quenching Does Not Prevent Kleptoplasts From Net Photoinactivation

“…Händeler et al, 2009). Our results are similar to those that were obtained in studies in which species have been starved under light intensities that exceeded their culturing light conditions and resulted in a significant reduction of kleptoplast photosynthesis, independently of the presence or absence of the XC and q E (Vieira et al, 2009;Klochkova et al, 2010;Christa et al, 2013Christa et al, , 2015. During the HL treatment our data align with those from Vieira et al (2009) in showing an exponential decrease of F v /F m , a pattern expected to occur in the absence of PSII repair (Campbell and Tyystjärvi, 2012).…”

“…For example, Elysia nicrocapitata was able to endure 5 months of starvation but kleptoplasts lost functionality after a couple of days (Klochkova et al, 2010). These 5 months even out-compete both Elysia species used here and others in which the kleptoplast are active for 2-3 months (Clark et al, 1981;Middlebrooks et al, 2012;Christa et al, 2014cChrista et al, , 2015.…”

Polymorphic adaptations in metazoans to establish and maintain photosymbioses

“…Cylindrobulla schuppi or Oxynoe antillarum , and most Limapontioidea (e.g. Placida dendritica ), are not able to ingest the kleptoplasts in a functional state and instead digest them rather quickly (Christa et al, ). By contrast, some members of the Costasiellidae, such as Costasiella ocellifera or C. kuroshimae and most Plakobranchaceae, e.g.…”

“…By contrast, some members of the Costasiellidae, such as Costasiella ocellifera or C. kuroshimae and most Plakobranchaceae, e.g. Elysia timida or Plakobranchus ocellatus , are able to retain photosynthetic activity in the kleptoplasts, even during starvation (Christa et al, , ; de Vries, Christa & Gould, ; Wägele & Martin, ).…”

Evolution of symbiosis in hermatypic corals: A model of the past, present, and future

“…There are precedents for such. • To be more specific, the possibility exists that the coral may ingest the dinoflagellates or another phytoplankton or alga, digest or pierce the cell wall during the digestive process, ingest the cytoplasm along with the intact chloroplasts, and move the chloroplasts to the intercellular areas to replace the zooxanthellae [77]. In this case, the temperature tolerance of the symbiont would become moot; only the temperature tolerance of the host and the chloroplasts would be important.…”