Format: ORAL

Elena M. Kramer1, Yang Gong1, Ya Min2, Evangeline Ballerini3, and Scott A. Hodges4

1Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA 2Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT USA 3Department of Biological Sciences, California State University, Sacramento, CA, USA 4Department of Ecology, Evolution and Marine Biology, University of CA, Santa Barbara, CA, USA

The lower eudicot model system Aquilegia possesses several morphological features that can shed light on the evolution of novelty, particularly in the context of complex organ form. We have been studying several key aspects of the Aquilegia flower but will focus today on the three-dimensional petal nectar spur. We have found that Aquilegia petal spurs initiate due to a localized region of cell division. This lays the ground pattern of the spur, which is then realized through anisotropic cell elongation. Diversification of spur morphology has involved multiple factors, including heterochronic shifts that generate much longer, narrower cells; differences in cell numbers around the radial axis of the spur and along its length; and independent control of both cell division and elongation on different surfaces of the spur, which generates curvature. We are now combining transcriptomics, candidate gene approaches, and QTL mapping to explore the genetic architecture of spur development and understand its evolution.