Mimault, M. | bioRxiv Science

bioRxiv2023

Non-local model of chemotaxis based on peer attraction

Movement is critical for bacterial species inhabiting soils because nutrient availability is limited and heterogeneously distributed both in space and time. Recent live microscopy experiments show that bacteria form flocks when navigating through porous medium, and complex cell-cell interactions may be required to maintain such flocks. Here we propose a non-local model to study how peer attraction can affect flocking patterns in a porous medium. We establish the existence and uniqueness of the solution of the problem, propose a numerical scheme for simulations of the non-local convection-diffusion equation, and investigate the numerical convergence of the scheme. Numerical simulations showed that the strength of peer attraction is critical to control the size, shape, and nature of movement of the flocks in a porous network. MSC Classification35F31, 92Cxx, 92-10

cell biology↗

bioRxiv2022

Cell-based model shows complex rearrangement of tissue mechanical properties are needed for roots to grow in hard soil

When exposed to increased mechanical resistance from the soil, plant roots display non-linear growth responses that can not be solely explained by mechanical principles. Here, we aim to investigate how changes in tissue mechanical properties are biologically regulated in response to soil strength. A particle-based model was developed to solve root-soil mechanical interactions at the cellular scale, and a detailed numerical study explored factors that affect root responses to soil resistance. Results showed that growth through increasing soil strength is maintained through the softening of cell walls at the tip, a response likely linked to soil cavity expansion. The model also predicts the shortening and decreased anisotropy of the zone of cell elongation, which may improve the mechanical stability of the root against axial forces. The study demonstrates the potential of advanced modeling tools to help identify traits that confer plant resistance to abiotic stress.

developmental biology↗