A case study on the re-establishment of the cyanolichen symbiosis: where do the compatible photobionts come from?

J.L.H. Cardós, M. Prieto, Maarit Johanna Jylhä, G. Aragón, M.C. Molina, I. Martínez, Jouko Rikkinen

Research output: Contribution to journalArticleScientificpeer-review


BACKGROUND AND AIMS: In order to re-establish lichen symbiosis, fungal spores must first germinate and then associate with a compatible photobiont. To detect possible establishment limitations in a sexually reproducing cyanolichen species, we studied ascospore germination, photobiont growth and photobiont association patterns in Pectenia plumbea.

METHODS: Germination tests were made with ascospores from 500 apothecia under different treatments, and photobiont growth was analysed in 192 isolates obtained from 24 thalli. We determined the genotype identity [tRNALeu (UAA) intron] of the Nostoc cyanobionts from 30 P. plumbea thalli from one population. We also sequenced cyanobionts of 41 specimens of other cyanolichen species and 58 Nostoc free-living colonies cultured from the bark substrate.

KEY RESULTS: Not a single fungal ascospore germinated and none of the photobiont isolates produced motile hormogonia. Genetic analyses revealed that P. plumbea shares Nostoc genotypes with two other cyanolichen species of the same habitat, but these photobionts were hardly present in the bark substrate.

CONCLUSIONS: Due to the inability of both symbionts to thrive independently, the establishment of P. plumbea seems to depend on Dendriscocaulon umhausense, the only cyanolichen species in the same habitat that reproduces asexually and acts as a source of appropriate cyanobionts. This provides support to the hypothesis about facilitation among lichens.
Original languageEnglish
JournalAnnals of Botany
Issue number3
Pages (from-to)379-388
Number of pages10
Publication statusPublished - 16 Aug 2019
MoE publication typeA1 Journal article-refereed

Fields of Science

  • 1181 Ecology, evolutionary biology
  • Ascospore germination
  • cyanolichen symbiosis
  • free-living Nostoc
  • Pectenia plumbea
  • photobiont association
  • photobiont-mediated guilds
  • tRNA(Leu) (UAA) intron

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