Oomycete and fungal pathogens threaten food, fiber, and forests around the world. With climate change, these pathogens are expected to emerge more frequently. Evolution can facilitate their emergence through mechanisms such as mutations that change or expand host range. Characterizing evolutionary mechanisms in plant pathogens will contribute to our ability...
Xanthomonas hortorum pv. carotae (Xhc) is an epiphytic, plant pathogenic bacterium that causes the disease bacterial blight of carrot (Daucus carota subsp. sativus). Infection with Xhc can result in blighting of leaves and umbels and reduce quality and yield of carrot seed crops. Carrot production in the United States approaches...
Pseudomonas syringae are plant pathogenic bacteria that cause disease by rapidly multiplying within the aboveground tissues of host plants. Growth of P. syringae within plant host tissues requires the disarmament of host immune defenses that limit microbial growth. To combat host defenses, P. syringae deploys a type III secretion system...
The climate of the Pacific Northwest is in flux, and existing forest ecosystems are stressed and poised to shift in fundamental ways, with or without human intervention. This dissertation probes the nature of forest responses to environmental change through investigations of morphology and genetics of three species of alder co-occurring...
Plant-parasitic nematodes (PPN) pose a severe threat to crop production with the economic losses due to nematode parasitism in excessive of US$ 80 billion each year. Meloidogyne incognita, a globally distributed pest with a diverse host range, contributes significantly to this economic loss. The most reliable way to manage PPN...
The role of small secreted peptides in plant defense responses to viruses has been seldom investigated. Here, we report a role for potato (Solanum tuberosum) PIP1, a gene predicted to encode a member of the PAMP-induced peptide (PIP) family, in the response of potato to potato virus Y infection (PVY)....
Photoacclimation is the process by which plants and phytoplankton adjust the concentration and composition of their photosynthetic machinery (i.e. their photoacclimation state) in response to changes in their light or nutrient environment. The purpose of photoacclimation is to balance the rate at which light energy is absorbed with the energetic...
Recent research in the UK has found that the wheat cultivar grown in the first year can have a significant impact on the amount of take-all that develops in the second year, regardless of the cultivar planted in year two. ‘Einstein’ is one such cultivar that reduces take-all disease (reduced...
Plant sexual reproduction requires a broad array of molecular mechanisms to proceed successfully. Some of these mechanisms are well-studied, but our knowledge of them as a whole is fundamentally incomplete. Pollen tube growth is a key part of this process, facilitating the delivery of the sperm cells to the female...
Potato Virus Y (PVY) is an enduring problem for potato production worldwide. Potato varieties that resist the “ordinary” strain PVYO were developed by breeders, but in recent years, recombinant strains of PVY have been able to circumvent this strain-specific resistance and evade growers and seed certification officials by causing fewer...