"Plant science is evolving from a reductionistic view on gene function to an integrated systems biology approach. Gene function of genes is now studied in the context of the dynamic behavior of physiological, cellular or developmental processes. Mathematical and computational modeling play a central role in this approach. During the initial Marie Curie Fellowship, I worked as a biomodeller at the primarily experimental VIB Department of Plant Systems Biology (PSB) in Ghent, Belgium. Based on this work, PSB has awarded me a “Young Leader” position, which includes a five year position as a group leader and budget for a PhD student. In this position, I have started up the group “Plant Systems Modeling” that is currently composed of myself (PI), a postdoc, three PhD students, and two Master’s students. The European Reintegration Grant would support further development of this group and thus ensure full reintegration. The Plant Systems Modeling group aims to build predictive models of auxin-driven tissue morphogenesis that can act as hypothesis-generators for wet-lab research. The project consists of the following two work packages: WP 1 To predict from first principles the spatio-temporal expression patterns of the major players of early vascular patterning in Arabidopsis, including PIN, AUX and auxin. This model will extend on the traveling-wave mechanism for auxin canalization that we have proposed recently (Merks et al, Trends in Plant Science, 2007). WP 2 To unravel the molecular mechanisms behind the recent observation that auxin oscillations regulate lateral root initiation (De Smet et al., Development 2007). For this we will develop a growing, multicellular model of auxin-flux-regulated patterning in the root basal meristem."