Genetic interaction between GL15 and FDL1 modulates juvenile cuticle deposition and leaf permeability in maize

The plant cuticle is a hydrophobic layer that serves as the primary barrier between plant surfaces and the external environment, limiting water loss and protecting against various stresses. This study investigates the genetic interaction between the maize ZmFDL1 and ZmGL15 genes and their role in modulating juvenile cuticle deposition and leaf permeability. The research was undertaken to understand how these genes influence cuticle composition and structure, which are crucial for plant protection against environmental stresses such as drought. We analysed the chemical composition of cutin and waxes, as well as cuticle-dependent leaf permeability. Our findings reveal that ZmFDL1 and ZmGL15 individually and synergically regulate the deposition of cuticular components, with significant impacts on leaf permeability. The gl15-S mutant exhibited an adult-like cuticle with higher cutin and lower wax contents, leading to reduced leaf permeability and improved water retention under drought conditions. These results highlight the importance of cutin in forming an effective water barrier and suggest that modulating cuticle composition with enhanced cutin content could be a strategy for improving drought tolerance in crops. This study provides new insights into the genetic regulation of cuticle biosynthesis and its relevance for plant adaptation to water scarcity. HighlightO_LIZmFDL1 and ZmGL15 interact to modulate cuticle composition and reduce leaf water loss. C_LIO_LIZmFDL1 and ZmGL15 genes regulate juvenile cuticle deposition in maize. C_LIO_LIThe gl15-S mutant shows an adult-like cuticle with higher cutin and lower wax contents. C_LIO_LIThe gl15-S mutation is epistatic to fdl1-1, partially rescuing the defective fdl1 cuticle phenotype. C_LIO_LIThe cuticle composition in gl15-S mutants leads to reduced leaf permeability and improved water retention under drought conditions. C_LIO_LICuticular layer with enhanced cutin content could improve drought tolerance in crops. C_LI