The configuration of the vacuole is driven by clathrin-mediated trafficking in root cells of Arabidopsis thaliana.

Abstract

The central vacuole is a multifunctional organelle with the most significant occupancy in a differentiated plant cell. Plants depend on the function of the vacuole for critical development, growth, and environmental responses. As the cell expands, the vacuole changes shape and size, increasing its membrane and luminal content. The set of these events is called the vacuolar configuration process, which is scarcely described. Our research highlights the impact of plasma membrane internalization on vacuole morphology during the vacuolar configuration process. We observed a direct correlation between differential endocytosis rates and the enrichment of vacuolar membranous structures. Chemical and genetic interference of Clathrin-Mediated Endocytosis (CME) revealed that it is required for the vacuolar configuration of growing root cells. The contribution of CME to the vacuole configuration process co-occurs with the induction of post-TGN/EE trafficking with the participation of the Rab GTPases ARA6 and ARA7. Our results show that the CME plays an active role during the vacuole configuration, most likely carrying the material that allows the establishment of the vacuole on elongating cells. Since membrane trafficking through the EE/TGN is required to reach the vacuole, additional actors must be defined.