Identifying a Candidate Mutation Underlying a Reduced Cuticle Wax Mutant of Rice Using Targeted Exon Capture and Sequencing

Aerial surfaces of terrestrial plants are protected from the uncontrolled loss of water and gas by the cuticle, a membrane of fatty acid polymers on the outer surface of epidermal cells. Composed of cutin and waxes, the cuticle protects against a wide range of external stresses and has an important role in plant development and reproduction. Plants with reduced cuticular waxes often exhibit glossy, bright green leaves, which in rice are only observed in the presence of water adhesion. In this study, a wet leaf/glossy (wlg) mutant KDS-2249D was subjected to targeted exon capture and sequencing to identify candidate mutations. A single nonsynonymous, homozygous mutation was found in the KDS-2249D mutant. The mutation (G1080A) is predicted to change a tryptophan at position 360 to a stop codon in the Glossy1-like-1/wax crystal-sparse leaf 2 gene. This mutation completely co-segregated with the wlg phenotype in an F2 mapping population (n = 435) and the KDS-2249D mutant exhibited a 40-50% decrease in total wax and significant increase in membrane permeability. This mutant will be useful for studies examining the role of cuticle waxes in protecting rice plants from environmental stresses.