Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2017

Erindi/veggspjald / Talk/poster V22

Distinctive characters of Nostoc genomes in cyanolichens

Höfundar / Authors: Andrey N. Gagunashvili and Ólafur S. Andrésson

Starfsvettvangur / Affiliations: Biology Institute, University of Iceland

Kynnir / Presenter: Ólafur S. Andrésson

Background: Cyanobacteria of the genus Nostoc are capable of forming symbioses with a wide range of organisms, cyanolichens being the largest and most diverse group. The ability to form symbiosis appears restricted to certain lineages of Nostoc, raising the question whether symbiotic competence is determined by characteristic genes.
Results: We present the complete genome sequencing, annotation and analysis of two Nostoc strains associated with bipartite and tripartite lichens, respectively. Comparison with other Nostoc genomes allowed identification of genes potentially involved in symbioses with a broad range of partners including lichen mycobionts. Some of the identified genes are presumably involved in the initial recognition and establishment of the symbiotic association, while others may confer advantage to cyanobionts during cohabitation with a mycobiont in the lichen symbiosis.
Conclusions: Our study presents the first genome sequencing and genome-scale analysis of lichen-associated Nostoc strains. These data provide insight into the molecular nature of the cyanolichen symbiosis and pinpoint candidate genes for further studies aimed at deciphering the genetic mechanisms behind the symbiotic competence of Nostoc. Since many phylogenetic studies have shown that Nostoc is a polyphyletic group that includes several lineages, this work also provides an improved molecular basis for demarcation of a Nostoc clade with symbiotic competence.