Multiple Mating Events and Spermatia-Mediated Gene Flow in the Lichen-Forming FungusLobaria pulmonaria

Abstract

Keller, C. & Scheidegger, C. 2016. Multiple mating events and spermatia-mediated gene flow in the lichen-forming fungus Lobaria pulmonaria. — Herzogia 29: 435–450.Lichen-forming fungi have developed combined reproductive strategies that involve both sexual and asexual propagules, which are produced in varying frequencies over space and time. Lobaria pulmonaria reveals the characteristic traits of genetically diverse, fully recombinant populations, despite the generally rare occurrence of sexual reproductive structures. This study aimed at investigating the genetic diversity of the progenies of single apothecia of L. pulmonaria from different populations. Because the percentage of germinating ascospores is often very small and single spore cultures are thus difficult to obtain, we tested a protocol of DNA isolation from a multispore fraction and identified the alleles of three fungus-specific microsatellite markers. Multispore samples analysed from single apothecia revealed two to three different alleles. This confirms a heterothallic mating system in L. pulmonaria and indicates multiple matings in single apothecia. Paternal thalli were found at different distances up to more than one hundred meters. Our results show that spermatia are an important source of gene flow with dispersal distances in the same order of magnitude as vegetative and sexual diaspores.