Abstract

Vesicle traffic is essential for cell homeostasis, growth and development in plants, as it is in other eukaryotes, and is facilitated by a superfamily of proteins known as soluble N‐ethylmaleimide‐sensitive fusion protein attachment protein receptors (SNAREs). Although SNAREs are well‐conserved across phylla, genomic analysis for two model angiosperm species available to date, rice and Arabidopsis, highlights common patterns of divergence from other eukaryotes. These patterns are associated with the expansion of some gene subfamilies of SNAREs, the absence of others and the appearance of new proteins that show no significant homologies to SNAREs of mammals, yeast or Drosophila. Recent findings indicate that the functions of these plant SNAREs also extend beyond the conventional ‘housekeeping’ activities associated with vesicle trafficking. A number of SNAREs have been implicated in environmental responses as diverse as stomata movements and gravisensing as well as sensitivity to salt and drought. These proteins are essential for signal transduction and response and, in most cases, appear also to maintain additional roles in membrane trafficking. One common theme to this added functionality lies in control of non‐SNARE proteins, notably ion channels. Other examples include interactions between the SNAREs and scaffolding or other structural components within the plant cell.