Chemical and Ultrastructural Changes in the Cuticle Observed in RabA2b Overexpressing Plants

The plant cuticle is a hydrophobic layer covering the cell wall that protects cells from pathogen invasion and water loss. In this study, we analyzed the cuticles of transgenic <i>Arabidopsis thaliana</i> plants overexpressing the vesicular trafficking small GTPase <i>RabA2b</i>. The <i>RabA2b</i>-overexpressing plants exhibited distinctive structural and chemical modifications in their cuticles, including enhanced hair-like wax crystals and increased accumulation of phenolic compounds such as ferulic acid and coumaric acid, which contribute to cutin cross-linking and reinforcement of the cuticle matrix. These chemical and structural changes were associated with improved barrier function and increased drought resistance. Our findings suggest the involvement of <i>RabA2b</i> in affecting the plant cell's exterior by altering the cuticle composition and architecture, thereby improving plant tolerance to water deficit.