Natural Diversity of Aquatic Oomycetes in the Lititz Run
We have been sampling oomycetes from Lititz Run at the Millport Conservancy over the past six years to assess biodiversity and also how species profiles change across seasons. We have used a combination of stream baiting and water filtration to isolate organisms. In 2012 we initiated a metagenomics approach to identify species using next-generation sequencing. Other researchers have suggested that aquatic oomycete biodiversity is considerably underestimated, so we hope this approach will help illuminate just how much we don’t know!
Oomycete Diversity in Asymptomatic Soybean Fields
With recent funding from the USDA-National Institute of Food and Agriculture, we have initiated a project sampling soil oomycete diversity from soybean fields in Southeastern PA using both traditional culturing approaches and metagenomics. Phytophthora sojae is an important pathogen of soybeans, and many Pythium species can also cause disease. We are particularly interested in sampling fields with no history of Phytophthora root rot or Pythium damping off disease to assess the ecological role of these “pathogens”.
Molecular Phylogenetics and Taxonomy of Oomycetes
Our lab generates DNA sequence data for the description of new species, and to determine how species are related to each other. We are also interested in using newer coalescent-based methods to reconstruct species trees among closely related, potentially interbreeding, lineages. Several complete genome sequences are available to aid in the development of new phylogenetic markers.
Comparative Genomics and the Evolution of Pathogenicity
One of our main interests in the Blair Lab is understanding how pathogenic organisms evolve from their non-pathogenic ancestors. What are the genomic changes associated with pathogenicity in eukaryotes? Are they conserved or have they evolved convergently among different lineages? Why are some pathogens host-specific when others have broad host ranges? Because oomycetes are so diverse ecologically, they are a great model system for teasing apart some of these important questions. We can also compare oomycetes to true Fungi; after 2 billion years of evolution, these two groups have converged on many traits. Genomic resources are rapidly accumulating for both groups, making this an opportune time to study the evolution of complex phenomena such as pathogenicity.