Genetic and hormonal feedbacks defining tissue polarity by broad brushes and fine PINs

Lead Research Organisation: John Innes Centre
Department Name: Contracts Office


In the past 2-3 decades, developmental biologists have made tremendous progress in identifying genes required for the specification of individual cell types of an organ and in describing how they interact in genetic networks. In comparison, very little is known about the mechanisms that regulate tissue polarity and overall organ patterning.
The Arabidopsis gynoecium provides an excellent system to study organ patterning and tissue specification with its partition into distinct domains. Interactions among key regulators of Arabidopsis gynoecium and fruit development have revealed a network of upstream transcription factor activities required for this division. Regulation of the plant hormone auxin is emerging as an immediate downstream output from these activities, and here we aim to understand the spatiotemporal information that is defined through interactions between a set of transcription factors and auxin during the patterning process.
Using the Arabidopsis gynoecium as a model system, we will test the hypothesis that auxin is recruited by the upstream network to direct organ patterning and tissue polarity through its regulated distribution, thereby allowing the formation of a functionally reproductive structure. We will use established reporter lines to monitor auxin distribution throughout wild-type gynoecium development as well as in mutants with defects in polarity establishment. We will also take a global transcriptomic approach to identify additional components and pathways involved in gynoecium patterning. Finally, computational simulations will be used to demonstrate how auxin fluxes are established to ensure appropriate gynoecium patterning.
Through these studies, we aim to reveal the mechanism by which tissue polarity is established in the Arabidopsis gynoecium to ensure the formation of a functional reproductive structure.


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