Slltpg3, a non-specific lipid transfer protein, acts on the cuticle synthetic pathway to delay water loss and softening of tomato fruit

Abstract

Non-specific lipid transfer proteins (nsLTPs) are a class of small, omnipresent proteins that are involved in the transport of cuticular wax and other cell wall precursors. Although the cuticle serves as an outer barrier that protects plants from abiotic and biotic stresses and maintains postharvest storage quality, the regulatory role of nsLTPs on the cuticle remains unclear. Here, we isolated the Slltpg3 gene (a member of the tomato nsLTPs family) from tomato (Solanum lycopersicum) and overexpressed Slltpg3 in Micro-Tom tomato cultivars. We found that Slltpg3-overexpression optimized cuticle characteristics by increasing cuticular wax, cutin content, and cuticle thickness and by decreasing cuticle permeability. Our results suggested that Slltpg3 gene is involved in dynamic cuticle synthesis by increasing the content of cuticular wax components and delaying fruit softening and dehydration. Thus, this study revealed a direct relationship between cuticle characteristics and fruit softening and dehydration and provided new insights into tomato adaptation under drought conditions.