Fungal phytochrome chromophore biosynthesis at mitochondria

Mitochondria are essential organelles because of their function in energy conservation. Here, we show an involvement mitochondria phytochrome-dependent light sensing fungi. Phytochrome photoreceptors found plants, bacteria, and fungi contain a linear, heme-derived tetrapyrrole as chromophore. Linearization heme requires oxygenases (HOs) which reside inside chloroplasts planta. Despite the poor degree conservation HOs, identified two candidates fungus Alternaria alternata. Deletion either one phenocopied phytochrome deletion. The enzymes had cooperative effect physically interacted with phytochrome, suggesting metabolon formation. was attached to surface C-terminal anchor (CTA) sequence HoxA. CTA necessary sufficient for mitochondrial targeting. affinity apoprotein HoxA 57,000-fold higher than holoprotein, kiss-and-go mechanism chromophore loading assembly platforms functional phytochrome. Hence, alternative approaches biosynthesis insertion into evolved plants