Phylogenomic tree of Cercozoa based on single-cell transcriptomes from 100 uncultured cells

Area of Science:

• Protistology
• Eukaryotic Phylogenomics
• Marine Biology

Background:

• Cercozoa are diverse, single-celled eukaryotes within the supergroup Rhizaria.
• Most Cercozoa are uncultured predatory protists, often underrepresented in phylogenetic studies.
• Existing research has limited insight into the full diversity of Cercozoa.

Purpose of the Study:

• To broadly sample and characterize the uncultured diversity of Cercozoa using single-cell transcriptomics.
• To construct a comprehensive phylogenetic tree of Cercozoa, incorporating previously unsampled groups.
• To identify novel lineages and understand the evolutionary relationships within Cercozoa.

Main Methods:

• Single-cell transcriptomics was employed to generate molecular data.
• Multigene phylogenetic analysis was used to build a comprehensive evolutionary tree.
• Morphological data was collected alongside molecular data for integrated analysis.

Main Results:

• A taxon-comprehensive multigene tree of Cercozoa was generated, increasing taxon sampling by over 300%.
• Five novel Cercozoa lineages and two lineages previously known only from environmental sequences were identified.
• Established clades like Thecofilosea and Phaeodaria were recovered, while others, such as Imbricatea, were not.

Conclusions:

• Single-cell transcriptomics provides valuable molecular and morphological data for phylogenomic studies.
• The generated phylogenetic framework is foundational for future research on Cercozoa biology and diversity.
• The study underscores the significant number of unsampled taxa and novel lineages within Rhizaria, particularly Cercozoa.