Lichen fungi do not depend on the alga for ATP production

Lichen fungi live in a symbiotic association with unicellular phototrophs and have no known aposymbiotic stage. A recent study postulated that some of them have lost mitochondrial oxidative phosphorylation and rely on their algal partners for ATP. This claim originated from an apparent lack of ATP9 , a gene encoding one subunit of ATP synthase, from a few mitochondrial genomes. Here we show that while these fungi indeed have lost the mitochondrial ATP9 , each retain a nuclear copy of this gene. Our analysis reaffirms that lichen fungi produce their own ATP. ### Competing Interest Statement The authors have declared no competing interest.