Bacterial and archaeal symbioses with protists

Area of Science:

• Microbiology
• Evolutionary Biology
• Cell Biology

Background:

• Single-celled organisms, including prokaryotes (bacteria and archaea) and microbial eukaryotes (protists), harbor most of life's genetic diversity.
• Symbioses between protists and prokaryotes are ancient, ecologically vital, and fundamental to eukaryotic evolution, evidenced by the origin of mitochondria.
• Current understanding of eukaryotic symbioses is heavily biased towards animal hosts, neglecting the vast diversity within protists.

Purpose of the Study:

• To provide a comprehensive overview of bacterial and archaeal symbioses with protist hosts.
• To examine the evolutionary, ecological, and cellular aspects of these microbial partnerships.
• To investigate the functional contributions of symbionts to their protist hosts.

Main Methods:

• Literature review and synthesis of existing research on protist-microbe symbioses.
• Comparative analysis of symbiotic systems across diverse protist lineages.
• Exploration of cell biological mechanisms underlying host-symbiont interactions.

Main Results:

• Protist-prokaryote symbioses are widespread and diverse, exhibiting varied evolutionary trajectories and ecological roles.
• These symbioses involve complex cellular and molecular interactions, influencing host cell biology.
• Evidence suggests diverse functional roles for symbionts, ranging from nutrient provisioning to metabolic support.

Conclusions:

• Symbiotic interactions between protists and prokaryotes represent a major, underappreciated domain of biological diversity.
• Studying these systems offers novel insights into the evolution of eukaryotes and the fundamental principles of symbiosis.
• Expanding the focus to protist symbioses will significantly broaden and enrich symbiosis theory.