Reproductive isolation is one of the main mechanisms for establishing and maintaining species barriers. Reproductive isolation is based on mechanisms that reduce the capacity of two (incipient) species to mate and sexually reproduce with each other. Reproductive isolation can be based both on external (ecological) or internal (molecular) factors. Therefore, it manifests itself on several different levels during reproduction, most importantly before (pre-zygotic) or after (postzygotic) formation of a zygote. Reproductive isolation has important impacts not only on evolutionary processes, but also on plant breeding and thus food security.
One part of this project focuses on pollinator-mediated pre-zygotic isolation in plants. Such isolation can evolve when floral signals attract specific, distinct pollinators in two groups of plants, leading to reduced exchange of gametes between these two groups. To understand the evolution of such different signals, we will analyze pollinator-mediated selection on floral signals. In addition, the role of herbivores in the evolution of floral signals will be studied. To understand the molecular bases of differences in signals, both genetic and epigenetic effects will be investigated. In the second sub-project, the focus is on interactions immediately preceding fertilization. Here we will investigate the molecular mechanisms of pollen tube reception, for which the FERONIA (FER) receptor-like kinase plays key role by controlling the access of the pollen tube to the embryo sac. In the project, the role of FER in interspecific crossing barriers will be studied. In addition, further genes involved in pollen tube reception will be identified by genome-wide association studies. Collectively, this project will lead to novel insights into the mechanisms and evolution of reproductive isolation in plants, a key component for the understanding of diversification and economic use of plants.