Adaptation through horizontal gene transfer in the cryptoendolithic red alga Galdieria phlegrea

Thriving in the hot, acidic, and metal-rich environments associated with geothermal areas is possible for only a few eukaryotes, with the Cyanidiophytina red algae (Cyanidium, Galdieria, and Cyanidioschyzon) being a famous example. These unicellular taxa can live in pH 0–4 and temperatures reaching up to 56°C [1Merola A. Castaldo R. De Luca P. Gambardella R. Musacchio A. Taddei R. Revision of Cyanidium caldarium: three species of acidophilic...