Tri-kingdom co-evolution: mechanisms and consequences of hybridization

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Orchids present an exceptional study system for investigating eco-evolutionary processes, as they relate to hybridization mechanisms, across plant, insect and fungal taxa. Orchids possess a combination of peculiar features including: leaky' species boundaries that confound popular species concepts; a variety of pollination and fertilization syndromes; and a complete reliance on mycorrhiza for germination. While each feature can be found in other plant families, the combination of all features in orchids presents an opportunity to integrate studies that better address ecological and genetic speciation mechanisms at both micro- and macro-evolutionary scales. Using field and genomic methods, I use a bog orchid (Platanthera) system to understand what drives speciation and hybridization mechanisms at the various stages of reproductive and ecological success: pollination, fertilization, chromosomal evolution and mycorrhizal specificity. This work will: 1) develop an orchid-based system to simultaneously study multiple factors and their complex interactions on the process of co-evolution and speciation; 2) investigate tri-kingdom species interactions and their ecological co-dependencies to better understand potential ecological and co-evolutionary thresholds; 3) define mechanisms that facilitate/hinder evolutionary processes; 4) unravel how limitations of ploidy and chromosomal architecture can limit genomic compatibility and functional hybridization; and 5) provide opportunities for student training across multiple taxa and disciplines. Translated knowledge from my research program has important applications for the management of vulnerable populations, horticultural propagation, increasing fruit set, fungal biosecurity and comparative genomics.