Investigation of the effect of AtWIN1/SHN1 overexpression on poplar trees

Background: Interactions between plants and the environment occur primarily at the leaf level. The plant cuticle consists of a menagerie of lipids, waxes and polymers merging to form an insoluble membrane to protect plant leaves from contamination. In Arabidopsis, wax Inducer1/shine1 (WIN1/SHN1) and its family members have demonstrated roles in wax biosynthesis and cutin formation, the primary component of the cuticle layer composition. Constitutive overexpression of the Arabidopsis WIN1/SHN1 (wax inducer1, shine1, AtWIN1/SHN1) gene has led to improved water stress tolerance, altered stomatal densities and morphological changes in leaf and flower development in Arabidopsis. Other expression studies using the WIN1/SHN1 gene have shown heightened defense responses and malformations of the cuticle. Materials and Methods: Constructs of AtWIN1/SHN1 were developed and used to genetically transform poplar trees that were later analyzed to verify presence of the construct. Results: A total of five transgenic lines with 100 ramets each were generated for water-use efficiency testing. All lines displayed glossy leaves, decreased stomatal densities and improved water-use efficiencies. Several lines presented similar phenotypes and water-use efficiencies but others were unique. Conclusion: This study used an inventive method to generate ornamental trees with improved water-use efficiencies as a proactive method for protecting water resources and resisting drought.