Combined computational modeling and experimental analysis integrating chemical and mechanical signals suggests possible mechanism of shoot meristem maintenance

Mikahl Banwarth-Kuhn, Kevin Rodriguez, Christian Michael, Calvin-Khang Ta, Alexander Plong, Eric Bourgain-Chang, Ali Nematbakhsh, Weitao Chen, Amit K. Roy-Chowdhury, G. Venugopala Reddy, Mark S. Alber

Abstract: Author summary A population of stem cells located at the growing tip of plants are critical for continued growth of the stem and formation of all above-ground organs. These cells divide in specific planes resulting in the layered organization of the shoot apical meristem (SAM) stem cell niche. Through a combination of biologically-calibrated computational model simulations, transient genetic perturbation experiments, and quantitative image analysis, we test three possible mechanisms of the regulation of cell division plane orientation and the direction of anisotropic cell expansion in the SAMs of Arabidopsis. Our analysis suggests that the transcription factor-WUSCHEL, plant hormone cytokinin, and mechanical stress regulate patterns of cell expansion and cell division plane orientation in a layer-specific fashion to maintain the layered structure and shape of SAMs which are critical for stem cell homeostasis.