Species recognition in tropical lichen-forming fungi

2009 REU Intern Gabrielle Lopez


Freshman Biology major at Roosevelt University

REU Mentor: Dr. Thorsten Lumbsch (Associate Curator, Botany)

Symposium Presentation Title: A Phylogenetic study of the genus Lecanora (Fungi: Ascomycota: Lecanoromycetes: Lecanorales)

Symposium Presentation Abstract: Species recognition in lichen-forming fungi is difficult at best when considering the different methods used in classification.  Historically, chemical and morphological characters are implemented to produce phylogeny.  In this study, a phylogenetic tree of the genus Lecanora is produced using morphological and molecular data.  Techniques that were applied include DNA extraction, PCR amplification, gel electrophoresis, DNA sequencing, and alignment.  Analysis of the molecular data was performed using Garle.  The tree positioned the specimens in the group subfusca, which was supported with bootstrap analysis.  Morphological characters of the specimens were studied and photographed to confirm placement on the tree.  This study could be improved by incorporating more genes in the analysis, along with morphological characters for all taxa.  The integration of morphological and molecular data, like those used in this study, could lead to a more complete phylogenetic tree of the lichen genus Lecanora.

Original Project Description: Fungi that form stable symbioses with photosynthetic partners (algae or cyanobacteria) are called lichens. These organisms have a relative simple morphology and species recognition is difficult, especially in tropical taxa. These are often known from few collections and their variability is poorly known. Thus, some species have been repeatedly described from different continents, while in other cases the same name was applied to taxa that look similar, but maybe different species, sometimes not even closely related. Molecular data help to distinguish between intraspecific variability and distinct differences between isolated lineages. In a NSF supported project on the tropical lichen family Thelotremataceae, the species distinction of tropical crustose lichens is studied using morphological, chemical, and molecular data in an integrated approach.

Research methods and techniques: REU participants in this project will receive training in molecular and organismal research methods. They will learn how important a combination of both methods is for an understanding of the diversity of life in tropical ecosystems. The training will include introduction to the literature, handling of herbarium specimens, microscopic examination of morphological characters, and chemical investigations, including thin-layer chromatography. Molecular methods will include DNA isolation, PCR and subsequent direct sequencing of certain gene regions. Subsequently, the analysis of DNA sequence data will be performed.