title: Integral control of plant gravitropism through the interplay of hormone signaling and gene regulation.
abstract: The interplay between hormone signaling and gene regulatory networks is instrumental in promoting the development of living organisms. In particular, plants have evolved mechanisms to sense gravity and orient themselves accordingly. Here, we present a mathematical model that reproduces plant gravitropic responses based on known molecular genetic interactions for auxin signaling coupled with a physical description of plant reorientation. The model allows one to analyze the spatiotemporal dynamics of the system, triggered by an auxin gradient that induces differential growth of the plant with respect to the gravity vector. Our model predicts two important features with strong biological implications: 1), robustness of the regulatory circuit as a consequence of integral control; and 2), a higher degree of plasticity generated by the molecular interplay between two classes of hormones. Our model also predicts the ability of gibberellins to modulate the tropic response and supports the integration of the hormonal role at the level of gene regulation.
authors.affiliation: Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-Universidad Politécnica de Valencia, Valencia, Spain. guirodta@ibmcp.upv.es
authors.forename: Guillermo
authors.initials: G
authors.lastname: Rodrigo
authors.forename: Alfonso
authors.initials: A
authors.lastname: Jaramillo
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Blázquez
mesh_terms: D003198:Computer Simulation; D025461:Feedback, Physiological; D018506:Gene Expression Regulation, Plant; D053263:Gene Regulatory Networks / Q000235:genetics; D018522:Gravitropism / Q000235:genetics*; D007210:Indoleacetic Acids / Q000378:metabolism; D007700:Kinetics; D008954:Models, Biological; D010937:Plant Growth Regulators / Q000378:metabolism*; D018521:Plant Physiological Phenomena / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D010944:Plants / Q000235:genetics*; D015398:Signal Transduction / Q000235:genetics*; D013269:Stochastic Processes
chemical_list: D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; D010940:Plant Proteins