Search for: All records

Foliicolous lichens are formed by diverse, highly specialized fungi that establish themselves and complete their life cycle within the brief duration of their leaf substratum. Over half of these lichen‐forming fungi are members of either the Gomphillaceae or Pilocarpaceae, and associate withTrebouxia‐like green algae whose identities have never been positively determined. We investigated the phylogenetic affinities of these photobionts to better understand their role in lichen establishment on an ephemeral surface. Thallus samples of Gomphillaceae and Pilocarpaceae were collected from foliicolous communities in southwest Florida and processed for sequencing of photobiont marker genes, algal cultivation and/orTEM. Additional specimens from these families and also fromAspidothelium(Thelenellaceae) were collected from a variety of substrates globally. Sequences fromrbcLand nuSSUregions were obtained and subjected to Maximum Likelihood and Bayesian analyses. Analysis of 37rbcLand 7 nuSSUalgal sequences placed all photobionts studied within the provisional trebouxiophycean assemblage known as theWatanabeaclade. All but three of the sequences showed affinities withinHeveochlorella, a genus recently described from tree trunks in East Asia. The photobiont chloroplast showed multiple thylakoid stacks penetrating the pyrenoid centripetally as tubules lined with pyrenoglobuli, similar to the two described species ofHeveochlorella. We conclude thatHeveochlorellaincludes algae of potentially major importance as lichen photobionts, particularly within (but not limited to) foliicolous communities in tropical and subtropical regions worldwide. The ease with which they may be cultivated on minimal media suggests their potential to thrive free‐living as well as in lichen symbiosis.