Physiological characterization and gene mapping of a novel cuticular wax-related mutant in barley ( Hordeum vulgare L.)

Cuticular wax is a type of lipid covering the surface of plants, which is directly related to crop stress resistance. Thus, it is important to study wax-related genes and their regulatory mechanism in wax biosynthesis pathway for improving stress resistance. In this study, a wax-deficient barley mutant barley cuticular wax1 ( bcw1 )was identified, and genetic analysis indicated that the trait was controlled by a single recessive nuclear gene. Phenotype observations showed that the tubule-shaped waxy crystals covering the sheath and stem epidermis of mutants disappeared, but there were no significant differences were detected in the leaf epidermis between mutant and wild type. Water loss results confirmed that the cuticular waxes and cutins improved water-holding capacity of plant. By combining the bulk segregant analysis (BSA) and specific locus amplified fragment sequencing (SLAF-seq) strategy, the wax-related gene BCW1 was located on chromosome 2H with a total length of 15.10 Mb. No cuticular wax-related genes have been reported in the 9 regions, indicating that BCW1 is a novel gene that plays roles in cuticular wax biosynthesis and wax crystals formation.