Acquired Phototrophy as an Evolutionary Path to Mixotrophy

Area of Science:

• Evolutionary biology
• Endosymbiosis research
• Photosynthesis

Background:

• Acquired photosynthesis enables heterotrophic organisms to become autotrophic.
• Transient chloroplast acquisition offers insights into endosymbiosis and organelle retention.
• Kleptoplasty, the stealing of chloroplasts, serves as a model for evolutionary intermediates.

Purpose of the Study:

• To investigate environmental conditions favoring chloroplast retention evolutionarily.
• To model the eco-evolutionary dynamics of kleptoplastidic lineages.
• To understand the role of trade-offs in shaping evolutionary endpoints.

Main Methods:

• Eco-evolutionary modeling approach.
• Adaptive dynamics analysis.
• Simulation of environmental factors and physiological trade-offs.

Main Results:

• Identified a spectrum of evolutionarily stable strategies: phagotrophy, phototrophy, and obligate kleptoplasty.
• Low-light environments and weak trade-offs favor phototrophy.
• Strong trade-offs between chloroplast retention and digestion favor obligate kleptoplasty.

Conclusions:

• Environmental niche and pre-existing physiological trade-offs are critical constraints on evolutionary pathways.
• Obligate kleptoplasty can be an evolutionary endpoint under specific trade-off conditions.
• The study clarifies the conditions under which transient photosynthesis can lead to stable autotrophy.