Genetically divergent algae shape an epiphytic lichen community on Jack Pine in Manitoba

Abstract

Algal genotypes should freely associate with different lichen fungi that grow in the same confined habitat giving the appearance of low levels of selectivity and specificity. If genetic compatibility between algal and fungal partners limits the combination of partners, then some degree of taxonomic specificity should be evident. This study examined the photobiont composition in a community of epiphytic lichens on Jack Pine to investigate selectivity and specificity. The objectives of the study were to infer algal identity, to infer photobiont dispersal, and to investigate the distribution of algal genotypes relative to the fungal partner. Photobiont variability was determined by Restriction Fragment Length Polymorphism (RFLP) and nucleotide sequences of the Internal Transcribed Spacer (ITS) of ribosomal DNA (rDNA). Seven species of lichen-forming fungi are reported to associate with five divergent algal genotypes, with only one species, Evernia mesomorpha, showing some degree of selectivity and specificity. The algae represent at least two species (Trebouxia jamesii and T. impressa) for the area confined to 200cm 2 on the north side of 20 Jack Pine trees. Gene flow was inferred in this tightly defined community of lichenized algae. The algal sharing and inferred gene flow may suggest that soredia provide a means of algal transport and distribution among lichen-forming fungi in the habitat.

Site factors controlling epiphytic lichen abundance in northern coniferous forests

“…The unicellular green alga Trebouxia simplex and related species (Doering and Piercey-Normore, 2009;Kroken and Taylor, 2009) as well as Trebouxia species of the Asterochloris group , namely T. erici (Gärtner, 1985), T. excentrica (Gärtner, 1985;Hildreth and Ahmadjian, 1981) and T. glomerata s.l. (Friedl, 1989;PierceyNormore and DePriest, 2001), are most common among boreal epiphytes.…”

Fungal specificity and selectivity for algae play a major role in determining lichen partnerships across diverse ecogeographic regions in the lichen‐forming family Parmeliaceae (Ascomycota)

“…; Piercey‐Normore , ; Hauck et al . ; Doering & Piercey‐Normore ; Fernández‐Mendoza et al . ; Pérez‐Ortega et al .…”

Morphological and phylogenetic study of algal partners associated with the lichen-forming fungus Tephromela atra from the Mediterranean region

“…Several monophyletic lineages were newly recognized (Kroken and Taylor 2000;Romeike et al 2002;Blaha et al 2006). Variable degrees of selectivity for the algal partners were found in different lichen-forming fungi (Kroken and Taylor 2000;Beck et al 1998Beck et al , 2002Doering and Piercey-Normore 2009). In none of these studies evidence for co-evolution of fungal and algal partners was reported.…”