Evolution of floral and fruit traits in the Brassicales

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Despite our fascination with the diversity of forms observed in plants, our understanding of how this variation has arisen is limited. As such, “What is the basis of morphological variation?” remains a key question in evolutionary biology. The goal of my research is to decipher changes that result in different forms of flowers and fruits. Floral traits are clearly important for pollinator interactions, yet there is a notable gap in our knowledge of evolutionary processes that underlie these features that may influence pollinator behaviour. Detailed knowledge of fruit developmental genetics and evolution is essential because seed dispersal is important for structuring plant communities and represents a key component of plant fitness. I study two closely related plant groups that represent an exemplary system because they vary in important floral and fruit traits. They are also closely related to the leading genetic model plant, facilitating a more informed supposition of which genetic changes may be involved to generate novel traits. Cleomaceae (spider flower family) exhibit many different types of flowers, including variation in the gland that provides nectar for pollinators and an unusual stalk that elevates reproductive structures. These features are understudied across angiosperms despite their clear relationships to pollination biology. A group within the mustard family is important because it includes crop species (e.g. canola, broccoli) and because the fruits are often segmented, a trait that dramatically alters seed dispersal. This complex trait has evolved multiple times, leading to the fundamental question of whether the same modification in fruit patterning pathways underlie separate evolutionary events. I take a comprehensive approach that combines multiple disciplines and, as such, will lead to substantial advancements in understanding plant evolution as well as provide broad training for Highly Qualified Personnel. Developmental studies will be conducted on a range of species. This approach provides fundamental data on how mature fruits and flowers are formed, which facilitates hypotheses on what genes may be responsible for morphological differences when combined with knowledge of genetics in model species. We will combine these data for a thorough picture of how traits have changed through time. Further we will test whether key traits evolve together and are correlated with increased number of species. We will describe patterns of comparative gene expression using multiple approaches, which are valuable in correlating a particular morphology with a gene expression pattern. For example, observing the same expression patterns in multiple genes in two species supports the hypothesis that the same pathway has been recruited in different evolutionary origins. Finally, we propose to move beyond correlation and conduct experiments that will directly test how these genes function in our system.