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 Arabidopsis thaliana plants overexpressing the vesicular trafficking small GTPase RabA2b. The RabA2b-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 RabA2b in affecting the plant cell’s exterior by altering the cuticle composition and architecture, thereby improving plant tolerance to water deficit.