ZmCER1, a putative ECERIFERUM 1 protein in maize, functions in cuticular wax biosynthesis and bulliform cell development

The cuticular wax, acting as the ultimate defense barrier, is essential for the normal morphogenesis of plant organs. Despite this importance, the connection between wax composition and leaf development has not been thoroughly explored. In this study, we characterized a new maize mutant, ragged leaf4 (rgd4), which exhibits crinkled and ragged leaves starting from the sixth leaf stage. The phenotype of rgd4 is conferred by ZmCER1, which encoding an aldehyde decarbonylase involved in wax biosynthesis. ZmCER1 function deficient mutant displayed reduced cuticular wax density and disordered bulliform cells (BCs), while ZmCER1 overexpressing plants exhibited the opposite effects, indicating that ZmCER1 regulates cuticular wax biosynthesis and BCs development. Additionally, as the density of cuticular wax increased, the water loss rate of detached leaf decreases, suggesting that ZmCER1 is positively correlated with plant drought tolerance.