From simple to supercomplex: mitochondrial genomes of euglenozoan protists

Area of Science:

• Eukaryotic cell biology
• Evolutionary biology
• Genomics

Background:

• Mitochondria, crucial for cellular energy, possess their own genomes.
• The phylum Euglenozoa comprises three sister groups: Euglenida, Diplonemea, and Kinetoplastea.
• Mitochondrial genome architecture and gene expression mechanisms are highly diverse within Euglenozoa.

Approach:

• This review highlights the diverse mitochondrial genome architectures.
• It examines the complex gene expression mechanisms in Euglenozoa.
• Focuses on comparative analysis across Euglenida, Diplonemea, and Kinetoplastea.

Key Points:

• Early-diverging euglenids exhibit simplified mitochondrial genomes and conventional gene expression.
• Diplonemea and Kinetoplastea display highly complex mitochondrial genomes and gene expression.
• Mitochondrial protein expression in these groups requires extensive post-transcriptional modifications.
• Diplonemids possess exceptionally complex mitochondrial genome organizations, with implications for ocean plankton research.

Conclusions:

• Significant evolutionary divergence in mitochondrial genome complexity and gene expression exists within Euglenozoa.
• The complexity observed in Diplonemea and Kinetoplastea necessitates sophisticated molecular machinery for gene expression.
• Further research into Diplonemea is crucial, given their abundance and unique mitochondrial organization.