Ecology and evolution of algal–fungal symbioses

Ecological interactions and symbiosis between algae and fungi are ancient, widespread, and diverse with many independent origins. The heterotrophic constraint on fungal nutrition drives fungal interactions with autotrophic organisms, including algae. While ancestors of modern fungi may have evolved as parasites of algae, there remains a latent ability in algae to detect and respond to fungi through a range of symbioses that are witnessed today in the astounding diversity of lichens, associations with corticoid and polypore fungi, and endophytic associations with macroalgae. Research into algal–fungal interactions and biotechnological innovation have the potential to improve our understanding of their diversity and functions in natural systems, and to harness this knowledge to develop sustainable and novel approaches for producing food, energy, and bioproducts.