Mycology: Rediscovery of a lost model fungus highlights the origin of mycorrhizal symbioses.

Summary Arbuscular mycorrhizae (AM) are the most frequent symbioses of land plants. By reisolating a long-lost fungus from nature, a new study cracks the genomics of an enigmatic fungal–cyanobacterial partnership and reestablishes a valuable model for understanding the AM symbiosis.