Integrative Species Delimitation in Californian Striped Coralroot Orchids

Mathilda Santee* and Craig Barrett, Department of Biology, West Virginia University, Morgantown, WV 26506

Field (Broad Category): Biology (Biological & Biochemical Sciences) 

Student’s Major: Biology 

Corallorhiza striata (striped coralroot) is a rare, leafless orchid, found in the western United States, Canada, and Mexico, that relies upon ectomycorrhizal fungi to obtain energy. With widespread populations, this orchid complex gives excellent insight into molecular and species evolution. Multiple populations and variants have formed across North America, including Corallorhiza striata var. striata, var. vreelandii; and two distinct species, C. bentleyi and C. involuta. Taxonomic status among members of this complex are poorly understood, but this information is crucial for conservation efforts in these rare orchids. Specifically, preliminary data show mixed evidence for genetic and morphological divergence between coastal Californian and Sierra Nevadan populations. We used three types of data to investigate these populations: morphology, genomics, and fungal associations. We are further conducting a novel approach to genotyping via Inter-Simple Sequence Repeats (ISSR) to determine evolutionary history, environmental niche overlap among populations, and adaptation to effectively target fungal host genotypes by means of single nucleotide polymorphism (SNP) detection. This protocol has the potential to be used across diverse subdisciplines in biology as an economical and straightforward sequencing tool. Impacts of this research include an increased understanding of the forces that drive diversification in mycoheterotrophic plant species, as well as awareness and conservation of this rare orchid complex. The overall goal is to accurately determine and draw species boundaries in the state of California, while creating a better definition of species for this plant and other species across the biosphere. 

Funding: WVU Department of Biology, WVU PSCoR Grant, and the American Orchid Society 

Program/mechanism supporting research/creative efforts: Biology 486 capstone