Lichen fungi do not depend on the alga for ATP production

Lichen fungi live in a symbiotic association and have no known aposymbiotic stage. A recent study postulated that some of them have lost 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. We show that while these fungi indeed have lost the mitochondrial ATP9, each retained a nuclear copy of this gene. Our analysis reaffirms that lichen fungi are autonomous in energy production.