Turnover of Lecanoroid Mycobionts and Their Trebouxia Photobionts Along an Elevation Gradient in Bolivia Highlights the Role of Environment in Structuring the Lichen Symbiosis.

Shifts in climate along elevation gradients structure mycobiont-photobiont associations in lichens. We obtained mycobiont (lecanoroid Lecanoraceae) and photobiont (Trebouxia alga) DNA sequences from 89 lichen thalli collected in Bolivia from a ca. 4,700 m elevation gradient encompassing diverse natural communities and environmental conditions. The molecular dataset included six mycobiont loci (ITS, nrLSU, mtSSU, RPB1, RPB2, and MCM7) and two photobiont loci (ITS, rbcL); we designed new primers to amplify Lecanoraceae RPB1 and RPB2 with a nested PCR approach. Mycobionts belonged to Lecanora s.lat., Bryonora, Myriolecis, Protoparmeliopsis, the "Lecanora" polytropa group, and the "L." saligna group. All of these clades except for Lecanora s.lat. occurred only at high elevation. No single species of Lecanoraceae was present along the entire elevation gradient, and individual clades were restricted to a subset of the gradient. Most Lecanoraceae samples represent species which have not previously been sequenced. Trebouxia clade C, which has not previously been recorded in association with species of Lecanoraceae, predominates at low- to mid-elevation sites. Photobionts from Trebouxia clade I occur at the upper extent of mid-elevation forest and at some open, high-elevation sites, while Trebouxia clades A and S dominate open habitats at high elevation. We did not find Trebouxia clade D. Several putative new species were found in Trebouxia clades A, C, and I. These included one putative species in clade A associated with Myriolecis species growing on limestone at high elevation and a novel lineage sister to the rest of clade C associated with Lecanora on bark in low-elevation grassland. Three different kinds of photobiont switching were observed, with certain mycobiont species associating with Trebouxia from different major clades, species within a major clade, or haplotypes within a species. Lecanoraceae mycobionts and Trebouxia photobionts exhibit species turnover along the elevation gradient, but with each partner having a different elevation threshold at which the community shifts completely. A phylogenetically defined sampling of a single diverse family of lichen-forming fungi may be sufficient to document regional patterns of Trebouxia diversity and distribution.

Taxonomic recognition of some species-level lineages circumscribed in nominal Rhizoplaca subdiscrepans s. lat. (Lecanoraceae, Ascomycota).

BACKGROUND: Rhizoplaca subdiscrepans (Nyl.) R. Sant., a saxicolous, placodioid lichen, is considered to have a worldwide distribution in warm-temperate to boreal-arctic areas in Asia, Europe and North America. However, recent studies have revealed that this species includes five unrecognized species-level lineages-'subd A, B, C, D and E'. During research focused on the diversity of saxicolous lichens in mountainous areas of southern Poland, some interesting representatives of the genus Rhizoplaca were found. The main aim of our study was to determine the taxonomic status of the collected specimens by means of molecular tools and a comparative analysis of similar herbarium materials. METHODS: Detailed morphological, anatomical and chemical examinations of reference material from Asia, Europe and North and South America focused primarily on a selected group of lecanoroid taxa with a placodioid thallus. In addition, 21 new generated sequences representing Lecanora pseudomellea, Protoparmeliopsis muralis, Rhizoplaca opiniconensis, R. subdiscrepans s. lat. and R. phaedrophthalma were selected for molecular study using the internal transcribed spacer region (ITS rDNA), together with 95 available GenBank sequences mainly from the genus Rhizoplaca. RESULTS: Polish specimens that clustered with members of a potential species-level lineage 'subd E' of Rhizoplaca subdiscrepans complex were recovered. Comprehensive analyses of the lichen group led us to the conclusion that lineage 'subd E' represents R. subdiscrepans s. str. and that the taxon appears to have a limited geographical distribution and specific habitat preferences. Furthermore, some of the recently defined species candidates within R. subdiscrepans s. lat.-'subd D' and 'subd A'-should be assigned to two previously known species of Rhizoplaca, namely R. opiniconensis (Brodo) Leavitt, Zhao Xin & Lumbsch and R. phaedrophthalma (Poelt) Leavitt, Zhao Xin & Lumbsch, respectively. These two species are characterized by phenotypic features observed as well in analyzed specimens representing lineages 'subd D' and 'subd A'. Moreover, the representatives of these lineages demonstrate some differences in occupied habitat and geographical range that also correspond with the indicated species. Additionally, it was found that Lecanora pseudomellea B.D. Ryan is a strongly supported monophyletic lineage within Rhizoplaca, and therefore an appropriate new combination for the species is proposed.

Neotypification of Protoparmeliopsis garovaglii and molecular evidence of its occurrence in Poland and South America.

Protoparmeliopsis garovaglii is a widely distributed placodioid lichen, which develops a distinctly rosette thallus, composed of elongated and strongly inflated to sinuous-plicate lobes. The taxon is characterised by high morphological plasticity and varied composition of secondary metabolites. However, the epithet was never typified. As such, the identity of P. garovaglii, in its strict sense, was unknown for a long time. Our phylogenetic ITS rDNA analyses, including newly generated sequences, show that European (Austria, Poland), North American (USA) and South American (Bolivia, Peru) specimens of P. garovaglii are placed in a strongly supported monophyletic clade, sister to P. muralis. We provide the first molecular evidence of the occurrence of P. garovaglii in South America (Bolivia and Peru) and the second record in Central Europe (Poland) was also provided. Furthermore, we neotypify P. garovaglii and it is reported here for the first time from Poland.