Real-time tracking of root hair nucleus morphodynamics using a microfluidic approach

Root hairs (RHs) are tubular extensions of root epidermal cells that favour nutrient uptake and microbe interactions. RH shows a fast apical growth, constituting a unique single cell model system to analyse cellular morphodynamics. In this context, live cell imaging using microfluidics recently developed to analyze root development is appealing, but high-resolution imaging is still lacking to study accurate spatiotemporal morphodynamics of organelles. Here, we provide a powerful coverslip based microfluidic device (CMD) which enables us to capture high resolution confocal imaging of Arabidopsis RH development with real-time monitoring of nuclear movement and shape changes. To validate the setup, we confirmed the typical RH growth rates and the mean nuclear positioning previously reported with classical methods. Moreover, in order to illustrate the possibilities offered by the CMD, we have compared the real-time variations in the circularity, area, and aspect ratio of nuclei moving in growing and mature RH. Interestingly, we observed higher aspect ratios in the nuclei of mature RH, correlating with higher speeds of nuclear migration. This observation opens the way for further investigations of the effect of mechanical constraints on nuclear shape changes during RH growth and nuclear migration and its role in RH and plant development.