College of Agriculture & Natural Resources

Permanent URI for this communityhttp://hdl.handle.net/1903/1598

The collections in this community comprise faculty research works, as well as graduate theses and dissertations.

Browse

Filters

2013 - 20142

Settings

Author: search.filters.author.Salgado-Salazar, Catalina

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Not as Ubiquitous as We Thought: Taxonomic Crypsis, Hidden Diversity and Cryptic Speciation in the Cosmopolitan Fungus Thelonectria discophora (Nectriaceae, Hypocreales, Ascomycota)
    (PLoS One, 2013-10-18) Salgado-Salazar, Catalina; Rossman, Amy Y.; Chaverri, Priscila
    The distribution of microbial species, including fungi, has long been considered cosmopolitan. Recently, this perception has been challenged by molecular studies in historical biogeography, phylogeny and population genetics. Here we explore this issue using the fungal morphological species Thelonectria discophora, one of the most common species of fungi in the family Nectriaceae, encountered in almost all geographic regions and considered as a cosmopolitan taxon. In order to determine if T. discophora is a single cosmopolitan species or an assemblage of sibling species, we conducted various phylogenetic analyses, including standard gene concatenation, Bayesian concordance methods, and coalescent-based species tree reconstruction on isolates collected from a wide geographic range. Results show that diversity among isolates referred as T. discophora is greatly underestimated and that it represents a species complex. Within this complex, sixteen distinct highly supported lineages were recovered, each of which has a restricted geographic distribution and ecology. The taxonomic status of isolates regarded as T. discophora is reconsidered, and the assumed cosmopolitan distribution of this species is rejected. We discuss how assumptions about geographically widespread species have implications regarding their taxonomy, true diversity, biological diversity conservation, and ecological functions.
  • Thumbnail Image
    Item
    MOLECULAR PHYLOGENY AND TAXONOMIC REVISION OF FUNGI IN THE GENUS Thelonectria AND RELATED SPECIES WITH Cylindrocarpon-LIKE ANAMORPHS
    (2014) Salgado-Salazar, Catalina; Chaverri, Priscila; Plant Science and Landscape Architecture (PSLA); Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    The genus Thelonectria and related species with Cylindrocarpon-like anamorphs are a group of perithecial ascomycetes in the family Nectriaceae that occur as saprobes and in few cases as pathogens of hardwood trees, shrubs or other plant substrates. Despite of being a key component of forest ecosystems around the world, species relationships and distribution are largely unknown. The objectives of this study were to: 1) infer species level phylogenetic relationships of the genus Thelonectria and related species with Cylindrocarpon-like anamorphs with uncertain classification, testing monophyly of each one of the groups studied; 2) delimit taxa, establishing taxon circumscriptions and providing brief descriptions; 3) resolve nomenclatural issues by identifying redundantly used names and synonyms; 4) provide identification tools, specifically, diagnostic keys and molecular data that can be used further as molecular barcodes; 4) provide distribution data and to take the first steps into the identification of speciation patterns observed in these fungi. To achieve these goals, herbarium materials, as well as freshly collected material obtained from the field or from fungal repositories were compared using phylogenetic analyses of multiple loci, morphology and geographic distribution. This research resulted in the narrower circumscription of the genus Thelonectria, not to contain one of the most common species in the group, T. jungneri. According to the results of the phylogenetic analyses it was found T. jungneri is a segregating clade that needs to be recognized as a different genus. For the genus Thelonectria, a total of 31 new species were described, and three new genera, closely related to Thelonectria were created to accommodate the diversity of other species with Cylindrocarpon-like anamorphs: Cinnamonectria gen nov. with C. cinnamomea as type taxon, Macronectria gen. nov. with M. jungneri as type taxon, and Tumenectria gen. nov. with T. laetidisca as type taxon. Species in this group of fungi present extensive morphological conservationism, representing a challenge for species identification without the use of molecular techniques, however offering a great opportunity to explore mechanisms of speciation and evolutionary diversification.