Mosses and lichens provide specific micro-habitats for pink pigmented facultative methylotrophs (PPFMs)
Abstract: Methylotrophic bacteria, also known as pink pigmented facultative methylotrophs (PPFMs) colonize the surfaces of almost all known plants and often exert beneficial functions for the host. Little is known about their occurrence on mosses and lichens. Here we selected two Sphagnum spp. (S. fallax and S. magellanicum) and Lobaria pulmonaria as representatives to study the abundance and diversity of associated methylotrophic bacteria. By isolation, three distinctive Methylobacterium species were detected but only one of them occurred in S. magellanicum at a much lower extent. Very acidic pH of S. magellanicum could partially explain the difference in Methylobacterium abundance compared to the morphologically similar species S. fallax. Phylogenetic analysis showed cryptogam-specific clades, indicating potentially new Methylobacterium species. To investigate further uncultivated methylotrophs, we have amplified the 16S rRNA genes from the metagenomic DNA with a broad-spectrum primer set; single strand conformation polymorphism (SSCP) was used to recover bands belonging to methylotrophs. By SSCP band sequencing we were able to detect abundant genera shared by the hosts, whereas rare species were host-specific. These results enhance our knowledge of mehtylotrophic bacteria in cryptogams and show the co-occurrence of shared and host-specific taxa.