An eceriferum locus, cer-zv, is associated with a defect in cutin responsible for water retention in barley (Hordeum vulgare) leaves

Drought limits plant growth and threatens crop productivity. A barley (Hordeum vulgare) ethylene imine-induced monogenic recessive mutant cer-zv, which is sensitive to drought, was characterized and genetically mapped in the present study. Detached leaves of cer-zv lost 34. 2 % of their initial weight after 1 h of dehydration. The transpiration was much higher in cer-zv leaves than in wild-type leaves under both light and dark conditions. The stomata of cer-zv leaves functioned normally, but the cuticle of cer-zv leaves showed increased permeability to ethanol and toluidine blue dye. There was a 50-90 % reduction in four major cutin monomers, but no reduction in wax loads was found in the cer-zv mutant as compared with the wild type. Two F₂ mapping populations were established by the crosses of 23-19 × cer-zv and cer-zv × OUH602. More polymorphisms were found in EST sequences between cer-zv and OUH602 than between cer-zv and 23-19. cer-zv was located in a pericentromeric region on chromosome 4H in a 10. 8 cM interval in the 23-19 × cer-zv map based on 186 gametes tested and a 1. 7 cM interval in the cer-zv × OUH602 map based on 176 gametes tested. It co-segregated with EST marker AK251484 in both maps. The results indicated that the cer-zv mutant is defective in cutin, which might be responsible for the increased transpiration rate and drought sensitivity, and that the F₂ of cer-zv × OUH602 might better facilitate high resolution mapping of cer-zv.