Identification and Characterization of Reduced Epicuticular Wax Mutants in Rice

Epicuticular wax forms the outermost protective barrier of the aerial surfaces of land plants, working in concert with other components of the plant cuticle to prevent uncontrolled loss of water and to provide protection against an array of external environmental stress. In this study, chemically-mutagenized populations of rice (Oryza sativa L.) derived from approximately 4 750 M2 families were screened for adhesion of water droplets resulting in a wet leaf/glossy (wlg) phenotype. Mutants were identified in 11 independently-derived M2 families. Scanning electron microscopy analysis confirmed the association of the wlg phenotype with changes in the epicuticular wax crystals of these plants. The phenotypes of five mutants (7-17A, 26.1, 524.2, 680.2, and 843.1) were confirmed to be the result of single recessive gene mutation. Evaluation of mutants from 3 (6-1A, 7-17A, and 11-39A) of 11 M2 families revealed significant reductions (> 50%) in surface wax content and increases in cuticle membrane permeability.