TY - JOUR T1 - Spot dynamics in a reaction-diffusion model of plant root hair initiation JF - bioRxiv DO - 10.1101/114876 SP - 114876 AU - Daniele Avitabile AU - Victor F. BreƱa-medina AU - Michael J. Ward Y1 - 2017/01/01 UR - http://biorxiv.org/content/early/2017/03/07/114876.abstract N2 - We study pattern formation aspects in a 2-D reaction-diffusion (RD) sub-cellular model characterizing the effect of a spatial gradient of a plant hormone distribution on a family of G-proteins associated with root-hair (RH) initiation in the plant cell Arabidopsis thaliana. The activation of these G-proteins, known as the Rho of Plants (ROPs), by the plant hormone auxin, is known to promote certain protuberances on root hair cells, which are crucial for both anchorage and the uptake of nutrients from the soil. Our mathematical model for the activation of ROPs by the auxin gradient is an extension of the model proposed by Payne and Grierson [PLoS ONE, 12(4), (2009)], and consists of a two-component generalized Schnakenberg RD system with spatially heterogeneous coefficients on a 2-D domain. The nonlinear kinetics in this RD system model the nonlinear interactions between the active and inactive forms of ROPs. By using a singular perturbation analysis to study 2-D localized spatial patterns of active ROPs, it is shown that the spatial variations in certain nonlinear terms in the reaction kinetics, due to the auxin gradient, lead to a slow spatial alignment of the localized regions of active ROPs along the longitudinal midline of the plant cell. Numerical bifurcation analysis, together with time-dependent numerical simulations of the RD system are used to illustrate 2-D localized patterns in the model, as well as the spatial alignment of localized structures. ER -