Sugar deficiency causes changes in cuticle permeability and cell wall composition that influence fruit postharvest shelf-life

Abstract

The cuticle is a protective layer synthesized by epidermal cells of the plants and consisting of cutin covered and filled by waxes. In tomato (Solanum lycopersicum) fruit, the thick cuticle embedding epidermal cells has crucial roles in the control of pathogens, water loss, cracking, and postharvest shelf-life. Tomato fruits with reduced expression of the tomato gene LIN5 encoding cell wall invertase exhibits decreases transpirational water loss. Transcriptomic, biochemical, histological, and biomechanical analysis identified several unsual features of RNAi-LIN5 cuticles and the data indicate that, perturbation of endogenous fruit sugar levels affects the composition of the tomato cuticle and cell wall architecture which are an integral and regulated part of the ripening program affecting the postharvest shelf-life. A model is proposed in which sugar levels affects the cuticle formation which has a direct effect in softening of intact tomato fruit both directly, by providing a physical support, and indirectly, by regulating water status.