Assessing host specialization in symbiotic cyanobacteria associated with four closely related species of the lichen fungus Peltigera

HE O'Brien*, J Miadlikowska, F Lutzoni

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)

85 Citations (Scopus)

Abstract

Heterocystous cyanobacteria form symbiotic associations with a wide range of plant and fungal hosts. We used a molecular phylogenetic approach to investigate the degree of host specialization of cyanobacteria associated with four closely related species of the lichenized fungus Peltigera, and to compare these strains with other symbiotic cyanobacteria. We conducted phylogenetic analyses on 16S, rbcLX, and trnL sequences from cyanobacteria associated with multiple specimens of each lichen species and from symbionts of other fungi and plants, as well as from free-living strains of Nostoc and related genera of cyanobacteria. The genus Nostoc comprises two divergent lineages, but symbiotic strains occur primarily within a single monophyletic lineage that also includes free-living representatives. Cyanobacteria from the same lichen species were often more closely related to strains from other species or to plant symbionts or free-living strains than to each other. These results indicate that host specialization is low for the genus Nostoc, and suggest that opportunities for coevolution with its partners may be rare.

Original languageEnglish
Pages (from-to)363-378
Number of pages16
JournalEuropean Journal of Phycology
Volume40
Issue number4
DOIs
Publication statusPublished - Nov 2005

Keywords

  • cyanobacteria
  • host association
  • lichens
  • molecular phylogenetics
  • Nostoc
  • Peltigera
  • specialization
  • specificity
  • symbiosis
  • 16S RIBOSOMAL-RNA
  • NOSTOC-CONTAINING LICHENS
  • HORIZONTAL GENE-TRANSFER
  • PHYLOGENETIC-RELATIONSHIPS
  • MOLECULAR CHARACTERIZATION
  • AZOLLA FERN
  • ANABAENA
  • DIVERSITY
  • SPECIFICITY
  • PHOTOBIONTS

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