Phylogenetic signal of photobiont switches in the lichen genus Pseudocyphellaria s. l. follows a Brownian motion model

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Date: June 2017
From: Symbiosis(Vol. 72, Issue 3)
Publisher: Springer
Document Type: Report
Length: 308 words

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Abstract :

To access, purchase, authenticate, or subscribe to the full-text of this article, please visit this link: http://dx.doi.org/10.1007/s13199-016-0458-z Byline: Romina Vidal-Russell (1), Maria Ines Messuti (1) Keywords: Evolutionary driver; Lichenized fungi; Photobiont switch; Speciation; Symbiosis Abstract: Lichen symbioses are defined as a symbiotic relationship between a mycobiont (generally an ascomycete) and one or more photobionts (green algae or/and cyanobacteria). It was proposed that cephalodia emancipation is an evolutionary driver for photobiont switch from chlorophyte to cyanobacteria. In this study we want to test the monophyly of cyanolichens and to measure the phylogenetic signal of the symbiotic relationship between cyanobacteria and a mycobiont partner in the lichen genus Pseudocyphellaria. This genus includes some species that have a chlorophyte as primary photobiont (and Nostoc in internal cephalodia), while others have only cyanobacteria. In a phylogenetic framework we measure the phylogenetic signal (or phylogenetic dispersion) as well as mapped photobiont switches performing stochastic character mapping. Results show that having cyanobacteria as main photobiont has a strong phylogenetic signal that follows a Brownian motion model. Seven clades in the phylogeny had an ancestor with cyanobacteria. Reversal to a green algae photobiont is rare. Several switches were estimated through evolutionary time suggesting that there was some flexibility in these traits along the phylogeny however, close relatives retained cyanobacteria as main photobiont throughout the cyanolichen's history. Photobiont switches from green algae to cyanobacteria might enhance ecotypical differentiation. These ecotypes could lead to several speciation events in the new lineage resulting in the phylogenetic signal found in this study. We give insights into the origin of lichen diversity exploring the photobiont switch in a phylogenetic context in Pseudocyphellaria s. l. as a model genus. Author Affiliation: (1) Departamento de Botanica, INIBIOMA, CONICET-Universidad Nacional del Comahue, Quintral 1250, 8400, Bariloche, Rio Negro, Argentina Article History: Registration Date: 21/10/2016 Received Date: 05/07/2016 Accepted Date: 21/10/2016 Online Date: 28/10/2016

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Gale Document Number: GALE|A497181398