Infrared stimulation of mitochondrial metabolism in deep-sea yeast expands the energetic framework of hydrothermal ecosystems.

Deep-sea hydrothermal vents are archetypal chemosynthetic ecosystems, yet the intense geothermal near-infrared (NIR) radiation emitted by black smoker chimneys remains a largely unexplored environmental factor. While infrared (IR)-driven photosynthesis has been described in vent-associated bacteria, whether deep-sea eukaryotes can biologically respond to geothermal NIR radiation has remained unknown. Here, we demonstrate that the vent yeast Rhodotorula mucilaginosa F-J1 exhibits wavelength-specific growth stimulation under NIR exposure through a previously unrecognized mitochondria-centered metabolic response. NIR exposure significantly enhanced growth beyond the effects of glucose supplementation and reduced the apparent activation energy for growth, consistent with enhanced cellular metabolism. Mechanistically, targeted inhibition and ultrastructural analyses identified mitochondrial oxidative phosphorylation and mitochondrial ribosomal activity as essential components of this response. Proteomic and heterologous expression analyses further identified the mitochondrial ribosomal protein MRPS18b as a key mediator of NIR-stimulated growth. These findings reveal a previously unrecognized capacity of deep-sea eukaryotic microbes to biologically respond to geothermal IR radiation and expand the known energetic framework of hydrothermal vent ecosystems beyond canonical chemosynthesis and photosynthesis.