Phasing out photosynthesis - and weaponising chlorophyll?

Area of Science:

• Evolutionary biology
• Molecular biology
• Parasitology

Background:

• Photosynthesis, the process of converting light energy into chemical energy, has been lost multiple times during eukaryote evolution.
• The retention of chlorophyll synthesis, a key component of photosynthesis, after its loss is a puzzling evolutionary phenomenon.

Purpose of the Study:

• To investigate the retention of chlorophyll synthesis in Apicomplexa parasites of corals after the loss of photosynthesis.
• To explore potential functional roles for retained chlorophyll synthesis in these parasitic organisms.

Main Methods:

• Phylogenetic analysis of Apicomplexa species.
• Genomic and transcriptomic analysis to identify genes involved in chlorophyll synthesis.
• Comparative analysis with photosynthetic and non-photosynthetic relatives.

Main Results:

• The study identified a group of Apicomplexa parasitising corals that retain the ability to synthesize chlorophyll despite lacking functional photosynthesis.
• Evidence suggests the evolutionary loss of photosynthesis is a recurring event in this group.

Conclusions:

• The retention of chlorophyll synthesis in non-photosynthetic Apicomplexa is confirmed.
• Potential functions for retained chlorophyll synthesis include organelle-to-nucleus signaling, molecular mimicry, or predator defense mechanisms.