Evolutionary Origins of Rhizarian Parasites

Abstract

The SAR group (Stramenopila, Alveolata, Rhizaria) is one of the largest clades in the tree of eukaryotes and includes a great number of parasitic lineages. Rhizarian parasites are obligate and have devastating effects on commercially important plants and animals but despite this fact, our knowledge of their biology and evolution is limited. Here, we present rhizarian transcriptomes from all major parasitic lineages in order to elucidate their evolutionary relationships using a phylogenomic approach. Our results suggest that Ascetosporea, parasites of marine invertebrates, are sister to the novel clade Apofilosa. The phytomyxean plant parasites branch sister to the vampyrellid algal ectoparasites in the novel clade Phytorhiza. They also show that Ascetosporea + Apofilosa + Retaria + Filosa + Phytorhiza form a monophyletic clade, although the branching pattern within this clade is difficult to resolve and appears to be model-dependent. Our study does not support the monophyly of the rhizarian parasitic lineages (Endomyxa), suggesting independent origins for rhizarian animal and plant parasites.

New barcoded primers for efficient retrieval of cercozoan sequences in high‐throughput environmental diversity surveys, with emphasis on worldwide biological soil crusts

“…S4). Their main limitation consisted in missing most of the divergent lineages that could be more related to Retaria than Cercozoa: Ascetosporea, Gromiidea and Reticulosida (He et al., ; Sierra et al., ). We could not retrieve any of those taxa from the environment in spite of the in silico test showing some matches for Gromia and for 15% of the Ascetosporea.…”

Single Cell Transcriptomics, Mega-Phylogeny, and the Genetic Basis of Morphological Innovations in Rhizaria

“…Recent phylogenomic analyses place Foraminifera either within Radiolaria, implying Radiolaria to be a paraphyletic group (Burki et al 2013; Sierra et al 2013; Sierra et al 2016) or as sister to Radiolaria (Cavalier-Smith et al 2015; Burki et al 2016; He et al 2016). However, these analyses lack two crucial pieces in the puzzle: representatives from Nassellaria, one of the major polycystine radiolarian orders, and S. zanclea , the only species of Taxopodida.…”

“…We have generated transcriptome data and protein sequences from both the missing Radiolaria groups. In addition, we have reduced the impact of missing data in earlier phylogenomic analyses (Sierra et al 2013; Cavalier-Smith et al 2015; Burki et al 2016; Sierra et al 2016) by adding genes to Foraminifera and a substantially larger sampling of other Rhizaria species.…”

Making sense of environmental sequencing data: Ecologically important functional traits of the protistan groups Cercozoa and Endomyxa (Rhizaria)

“…The main taxonomic subdivisions are: (a) Endomyxa including Vampyrellida, Phytomyxea, Filoreta , Gromia and Ascetosporea (Bass et al, ; Sierra et al, ); (b) Cercozoa including the classes Sarcomonadea, Thecofilosea, Granofilosea, Imbricatea, Chlorarachnea and Metromonadea (Cavalier‐Smith et al, ); and (c) the incertae sedis rhizarian clades Aquavolonida, Tremulida and Novel Clade 12 (Bass et al, ).…”