Could a cuticle be an active component of plant immunity?

Abstract

The cuticle is the first physical barrier between the plant and the outer environment. The cuticle is no longer viewed as a rigid "inert sealer". Components of the cuticle were found to be responsive in their function and chemical composition to environmental signals. Cuticle creation is energy-consuming and complicated. Thus, cuticle composition and renewal dynamics are precisely regulated. Activated plant immunity is also energy "expensive". We briefly summarised our knowledge of the involvement of cuticle in plant-microbe interactions. Changes in cuticle amount and composition affect plant resistance to pathogens and treatment with cutin monomers triggers plant immunity. However, our knowledge about the effects of activated plant immunity on cuticle is scarce. We hypothesise that activated immunity influences cuticle dynamics. Our in-silico gene expression analysis revealed that cuticle biosynthetic genes are modulated under conditions simulating activated immunity. The analysis indicates that the cuticle is not just a rigid component of a plant reaction to the pathogen attack. Strengthening of the cuticle could prevent pathogen penetration. However, inhibition of cuticle production could save the energy needed for plant immunity. We propose questions which should be addressed in future research. Answering them would lead to a better understanding of plant defence against pathogens.

Keywords

• cuticle dynamics
• gene expression
• microbe penetration
• plant immunity
• wax