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Ecological specialization in Trebouxia (Trebouxiophyceae) photobionts of Ramalina menziesii (Ramalinaceae) across six range‐covering ecoregions of western North America
Author(s) -
Werth Silke,
Sork Victoria L.
Publication year - 2014
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.3732/ajb.1400025
Subject(s) - biology , range (aeronautics) , biological dispersal , lichen , ecology , phylogeography , botany , phylogenetics , population , biochemistry , materials science , demography , sociology , gene , composite material
• Premise of the study: Many lichens exhibit extensive ranges spanning several ecoregions. It has been hypothesized that this wide ecological amplitude is facilitated by fungal association with locally adapted photobiont strains. • Methods: We studied the identity and geographic distribution of photobionts of the widely distributed North American lichen Ramalina menziesii based on rbcL (chloroplast DNA) and nuclear ribosomal ITS DNA sequences. To test for ecological specialization, we associate photobiont genotypes with local climate and phorophyte. • Key results: Of the photobiont lineages of R. menziesii , 94% belong to a clade including Trebouxia decolorans . The remaining are related to T. jamesii . The photobionts showed (1) significant structure according to ecoregion and phorophyte species and (2) genetic associations with phorophyte species and climate. • Conclusions: Geography, climate, and ecological specialization shape genetic differentiation of lichen photobionts. One great advantage of independent dispersal of the fungus is symbiotic association with locally adapted photobiont strains.