Genetic combinations of symbionts in a vegetatively reproducing lichen, Parmotrema tinctorum , based on ITS rDNA sequences (original) (raw)
Related papers
Lichenologist, 2013
Photobiont diversity within populations of Xanthoria parietina was studied at the species level by means of ITS analyses and at the subspecific level with fingerprinting techniques (RAPD-PCR) applied to sterile cultured algal isolates. Populations from coastal, rural and urban sites from NW, SW and central France and from NE Switzerland were investigated. Between 8 and 63 samples per population, altogether 150 isolates, were subjected to phenetic and ordination analyses. Epiphytic samples of X. parietina associated with different genotypes of Trebouxia decolorans but saxicolous samples contained T. arboricola. For comparison the T. gelatinosa photobiont of a small population of Teloschistes chrysophthalmus (4 samples) was investigated. ITS sequences of T. decolorans isolates from different geographic locations were largely similar. In all populations a surprisingly high diversity of genotypes was observed in Trebouxia isolated from lichen thalli growing side by side. As Trebouxia spp. are assumed to be asexually reproducing haplonts, the genetic background of this diversity is discussed. Fingerprinting techniques are a powerful tool for obtaining valuable insights into the genetic diversity within the algal partner of lichen-forming fungi at the population level, provided that sterile cultured isolates are available.
Annals of Botany, 2014
Aims The integrity and evolution of lichen symbioses depend on a fine-tuned combination of algal and fungal genotypes. Geographically widespread species complexes of lichenized fungi can occur in habitats with slightly varying ecological conditions, and it remains unclear how this variation correlates with symbiont selectivity patterns in lichens. In an attempt to address this question, .300 samples were taken of the globally distributed and ecologically variable lichen-forming species complex Tephromela atra, together with closely allied species, in order to study genetic diversity and the selectivity patterns of their photobionts. † Methods Lichen thalli of T. atra and of closely related species T. grumosa, T. nashii and T. atrocaesia were collected from six continents, across 24 countries and 62 localities representing a wide range of habitats. Analyses of genetic diversity and phylogenetic relationships were carried out both for photobionts amplified directly from the lichen thalli and from those isolated in axenic cultures. Morphological and anatomical traits were studied with light and transmission electron microscopy in the isolated algal strains. † Key Results Tephromela fungal species were found to associate with 12 lineages of Trebouxia. Five new clades demonstrate the still-unrecognized genetic diversity of lichen algae. Culturable, undescribed lineages were also characterized by phenotypic traits. Strong selectivity of the mycobionts for the photobionts was observed in six monophyletic Tephromela clades. Seven Trebouxia lineages were detected in the poorly resolved lineage T. atra sensu lato, where co-occurrence of multiple photobiont lineages in single thalli was repeatedly observed. † Conclusions Low selectivity apparently allows widespread lichen-forming fungi to establish successful symbioses with locally adapted photobionts in a broader range of habitats. This flexibility might correlate with both lower phylogenetic resolution and evolutionary divergence in species complexes of crustose lichen-forming fungi.
The Lichenologist, 2013
Photobiont diversity within populations of Xanthoria parietina was studied at the species level by means of ITS analyses and at the subspecific level with fingerprinting techniques (RAPD-PCR) applied to sterile cultured algal isolates. Populations from coastal, rural and urban sites from NW, SW and central France and from NE Switzerland were investigated. Between 8 and 63 samples per population, altogether 150 isolates, were subjected to phenetic and ordination analyses. Epiphytic samples of X. parietina associated with different genotypes of Trebouxia decolorans but saxicolous samples contained T. arboricola. For comparison the T. gelatinosa photobiont of a small population of Teloschistes chrysophthalmus (4 samples) was investigated. ITS sequences of T. decolorans isolates from different geographic locations were largely similar. In all populations a surprisingly high diversity of genotypes was observed in Trebouxia isolated from lichen thalli growing side by side. As Trebouxia sp...
The New phytologist, 2015
We studied the evolutionary history of the Parmeliaceae (Lecanoromycetes, Ascomycota), one of the largest families of lichen-forming fungi with complex and variable morphologies, also including several lichenicolous fungi. We assembled a six-locus data set including nuclear, mitochondrial and low-copy protein-coding genes from 293 operational taxonomic units (OTUs). The lichenicolous lifestyle originated independently three times in lichenized ancestors within Parmeliaceae, and a new generic name is introduced for one of these fungi. In all cases, the independent origins occurred c. 24 million yr ago. Further, we show that the Paleocene, Eocene and Oligocene were key periods when diversification of major lineages within Parmeliaceae occurred, with subsequent radiations occurring primarily during the Oligocene and Miocene. Our phylogenetic hypothesis supports the independent origin of lichenicolous fungi associated with climatic shifts at the Oligocene-Miocene boundary. Moreover, div...
Spatial patterns of photobiont diversity in some Nostoc-containing lichens
New Phytologist, 2000
Patterns of photobiont diversity were examined in some Nostoc-containing lichens using the nucleotide sequence of the cyanobacterial tRNA Leu (UAA) intron. Lichen specimens collected in northwestern USA were analysed and the sequence data were compared with tRNA Leu (UAA) intron sequences previously obtained from lichens in northern Europe. Generally, it is the species identity of a lichen rather than the geographical origin of the specimen that determines the identity of the cyanobiont. Identical intron sequences were found in Peltigera membranacea specimens collected in Oregon (USA) and in Sweden, and very similar sequences were also found in Nephroma resupinatum thalli collected in Oregon and Finland. Furthermore, in mixed assemblages where two Peltigera species grew in physical contact with each other, the different lichen species housed different photobiont strains. There is however not a one-to-one relation between mycobiont and photobiont as some intron sequences were found in more than one lichen species, and different intron sequences were found in different samples of some lichen taxa. Peltigera venosa exhibited a higher level of photobiont diversity than any other lichen species studied, and several intron sequences could for the first time be obtained from a single thallus. It is not clear whether this is evidence of lower cyanobiont specificity, or reflects an ability to exhibit different degrees of lichenization with different Nostoc strains. In one specimen of P. venosa, which contained bipartite cyanosymbiodemes and tripartite, cephalodiate thalli, both thallus types contained the same intron sequence.
The Lichenologist, 2021
To facilitate population-genetic studies, we developed simple sequence repeat (SSR) markers and a molecular species identification assay for Peltigera membranacea (Ascomycota, Peltigerales), a common ground-dwelling lichen of forest and tundra ecosystems. Additional markers were developed for its Nostoc photobiont. Twenty-one fungal markers for P. membranacea were found to be polymorphic, with the number of alleles ranging from 3–21. Nei's unbiased gene diversity ranged from 0.588 to 0.640 in four significantly structured (FST = 0.059) mycobiont populations. For the Nostoc photobiont, 14 polymorphic SSR were developed, yielding 4–14 alleles each, with gene diversity ranging from 0.062 to 0.771 in four populations showing substantial population structure (FST = 0.278). The new markers developed are suitable for population genetic studies of Peltigera membranacea and of its cyanobiont, and at the same time allowed us to distinguish 98.5% of P. membranacea specimens from morphologi...
Multiple Origins of Lichen Symbioses in Fungi Suggested by SSU rDNA Phylogeny
Science, 1995
The crustose lichen L&eanora disperss. lichen symbioses, associations between fungi and algae, have originated multiple times during fungal evolution. At least one successful establishment of symbiosis led to the more than 6000 species of the order l ecanorales, represented here by L. dispersa. The white-rimmed c ups (between 0.3 and 0.7 millimeter in diameter) emerging from the rock substrate produce the meiotic spores of th is fungal symbiont. See Phylogenetic hypotheses provide a context for examining the evolution of heterotrophic lifestyles. The lichen lifestyle, which is the symbiotic association of fungi with algae, is found in varIous representatives of Dicaryomycotina, both Ascomycetes and Basidiomycetes. A highly resolved parsimony analysis of small subunit ribosomal DNA (SSU rONA) sequences suggests at least five Independent origins of the lichen habit in disparate groups of Ascomycetes and Basidiomycetes. Because lichen associations arose from parasitic, mycDfThizal. or free-living saprobic fungi, neither mutualism nor parasitism should be construed as endpoints in symbiont evolution.
Photobiont Diversity in Lichen Symbioses From Extreme Environments
Frontiers in Microbiology
Fungal–algal relationships—both across evolutionary and ecological scales—are finely modulated by the presence of the symbionts in the environments and by the degree of selectivity and specificity that either symbiont develop reciprocally. In lichens, the green algal genus Trebouxia Puymaly is one of the most frequently recovered chlorobionts. Trebouxia species-level lineages have been recognized on the basis of their morphological and phylogenetic diversity, while their ecological preferences and distribution are still only partially unknown. We selected two cosmopolitan species complexes of lichen-forming fungi as reference models, i.e., Rhizoplaca melanophthalma and Tephromela atra, to investigate the diversity of their associated Trebouxia spp. in montane habitats across their distributional range worldwide. The greatest diversity of Trebouxia species-level lineages was recovered in the altitudinal range 1,000–2,500 m a.s.l. A total of 10 distinct Trebouxia species-level lineage...