Gregarine single-cell transcriptomics reveals differential mitochondrial remodeling and adaptation in apicomplexans

Area of Science:

• Microbiology
• Evolutionary Biology
• Parasitology

Background:

• Apicomplexa are unicellular parasites, including human pathogens like Plasmodium.
• Data on invertebrate-infecting gregarines and their evolutionary links are limited.
• Mitochondrial and plastid variations exist, with Cryptosporidium lacking both.

Purpose of the Study:

• To investigate the evolutionary relationships of gregarines within Apicomplexa.
• To characterize the mitochondrial metabolism of gregarines.
• To understand evolutionary patterns of mitochondrial reduction in apicomplexans.

Main Methods:

• Transcriptome sequencing of five gregarine species.
• Phylogenomic analyses integrating gregarine and other apicomplexan data.
• In silico characterization of mitochondrial pathways.

Main Results:

• Phylogenomic analysis supports Cryptosporidium as the earliest diverging apicomplexan lineage.
• Mitochondria have convergently reduced across apicomplexans.
• The electron transport chain was lost independently three times, twice within gregarines.

Conclusions:

• Apicomplexan mitochondrial metabolism is functionally restructured due to parasitism and anaerobiosis.
• Convergent evolution is prevalent in apicomplexans, affecting morphology, energy metabolism, and intracellularity.