Shoot and root phenotyping of the barley mutant kcs6 {3-ketoacyl-CoA synthase6) depleted in epicuticular waxes under water limitation

摘要

Aerial parts of plants are separated from the environment by a cuticle which functions in protection against desiccation and pathogen attack. Recently, we reported on a barley mutant with defect in the 3-KETOACYL-CoA-SYNTHASE (HvKCS6) gene, resultingin reduced coverage of the cuticle with epicuticular waxes. Spores of adapted and non-adapted powdery mildew fungi germinated less frequently on mutant leaves possibly because plant derived signals are missing. We used a shoot and root phe-notyping facility to test whether depletion in epicuticular waxes negatively impacts plant performance under water-limiting conditions. While shoots of mutant plants grew slower at well-watered conditions than wild-type plants, they showed an equal or slightly bettergrowth rate at water limitation. Also for roots, differences between mutant and parental line were less prominent at water-limiting as compared to well-watered conditions. Our results challenge the intuitive belief that reduced epicutic-ular wax might become a drawback at water limitation.