Research Fellows Directory
Dr Anthony Bishopp
University of Nottingham
Patterning of organs involves the organization of cell fates within a tissue in space and time. Researchers have focused on aspects of pattern formations that are controlled by deterministic mechanisms. Such mechanisms will be encoded through molecular networks of gene products and signalling molecules. However there is increasing evidence that either environmental factors or random perturbations of these systems play essential roles in creating stable biological patterns in processes ranging from flower development in plants to flagella length in Chlamydomonas. We work with the root vascular system of the small weed, Arabidopsis thaliana, as a model for understanding pattern formation in plants. During early embryonic development Arabidopsis roots have a radially symmetric pattern, but an asymmetric input of the hormone auxin from the two cotyledons forces the vascular cylinder to develop a diarch pattern with two xylem poles. Molecular analyses and mathematical approaches have uncovered the regulatory circuit that propagates this initial auxin asymmetry into a stable cellular pattern. The diarch pattern seen in Arabidopsis, is relatively uncommon, with most flowering plants having between three and eight xylem poles. Recently we have used multiscale mathematical modeling to demonstrate that this regulatory module does not rely on an asymmetric auxin input to specifying vascular pattern. Instead this can organize dynamically, with final pattern being dependent upon spatial constraints and growth. The predictions of our simulations compare with experimental observations of xylem pole number across a range of species as well as in transgenic systems in Arabidopsis where we manipulate the size of the vascular cylinder. Through considering the spatial constraints, we are now generating a theory to explain the diversity in vascular pattern seen across flowering plants.
Interests and expertise (Subject groups)