When: Monday, August 24, 2026 7–9PM (7–7:30 Social Time, 7:30–9 Presentation)
Where: Gates Hall Denver Botanic Gardens
What:
Dr. Jane E. Stewart is an Associate Professor of Plant Pathology in the Department of Agricultural Biology at Colorado State University in Fort Collins, CO, USA. She has degrees in Forestry from the University of Vermont and Plant Pathology from Washington State University. Her work at CSU is focused on forest and tree pathogens and their interactions with their hosts, vectors, and associated microbial communities. Dr. Stewart has extensive experience in fungal biology, population genetics and genomics, molecular diagnostics, and management of plant pathogens, including invasive and emerging pathogens of trees. Dr. Stewart also currently teaches two undergraduate classes, Forest and Tree Health which focused on forest diseases and insect pests and their management and Mushrooms, Molds and Mycorrhizae that is focused on a fungi in society. She also teaches graduate classes including Fungal Biology and Genetics and Forest Health Issues. Her research program at Colorado State University is focused on tree pathogens globally to better understand the biology, ecology and genetics, and management of emerging tree pathogenic fungi. Dr. Stewart is also currently Editor in Chief of the internationally recognized Forest Pathology Journal.
Her presentation is entitled ‘Pathogen evolution in the era of globalism: case study with invasive Cronartium ribicola and native Cronartium comandrae hybrids in North America’
Invasive pathogenic fungi threaten tree species resulting in possible fundamental ecosystem changes around the globe. Besides being more aggressive towards new hosts, non-native fungal species carry additional risks to the health of forest ecosystems via interactions with native species. Interspecific hybridization plays a key role in the evolution and emergence of novel fungal pathogens, and when it occurs between native and invasive species, can lead to unforeseen and potentially serious consequences. This presentation will discuss the temporal and spatial distribution and genetic evidence of a recently detected hybrid (Cronartium x flexili). This hybrid arises between two forest pathogens Cronatrium ribicola, the invasive causal agent of white pine blister rust, and Cronartium comandrae, the native causal agent of comandra blister rust. These findings demonstrate ongoing hybridization and asymmetric introgression between invasive and native forest rust pathogens, demonstrating a potential mechanism for the emergence of novel genotypes with altered evolutionary potential. Hybrid expansion into the large range of susceptible pines could have cascading impacts on forest ecosystem health.
Zoom:
https://us02web.zoom.us/j/84113035852?pwd=yXNHTb8LKemWYNngXQITD67O0j5ByH.1