Rice <i>OsGL1-6</i> Is Involved in Leaf Cuticular Wax Accumulation and Drought Resistance

<div><p>Cuticular wax is a class of organic compounds that comprises the outermost layer of plant surfaces. Plant cuticular wax, the last barrier of self-defense, plays an important role in plant growth and development. The <i>OsGL1-6</i> gene, a member of the fatty aldehyde decarbonylase gene family, is highly homologous to <i>Arabidopsis CER1</i>, which is involved in cuticular wax biosynthesis. However, whether <i>OsGL1-6</i> participates in cuticular wax biosynthesis remains unknown. In this study, an <i>OsGL1-6</i> antisense-RNA vector driven by its own promoter was constructed and introduced into the rice variety Zhonghua11 by <i>Agrobacterium</i>-mediated transformation to obtain several independent transgenic plants with decreased <i>OsGL1-6</i> expression. These <i>OsGL1-6</i> antisense-RNA transgenic plants showed droopy leaves at the booting stage, significantly decreased leaf cuticular wax deposition, thinner cuticle membrane, increased chlorophyll leaching and water loss rates, and enhanced drought sensitivity. The <i>OsGL1-6</i> gene was constitutively expressed in all examined organs and was very highly expressed in leaf epidermal cells and vascular bundles. The transient expression of <i>OsGL1-6-GFP</i> fusion indicated that OsGL1-6 is localized in the endoplasmic reticulum. Qualitative and quantitative analysis of the wax composition using gas chromatography-mass spectrometry revealed a significantly reduced total cuticular wax load on the leaf blades of the <i>OsGL1-6</i> antisense-RNA transgenic plants as well as markedly decreased alkane and aldehyde contents. Their primary alcohol contents increased significantly compared with those in the wild type plants, suggesting that <i>OsGL1-6</i> is associated with the decarbonylation pathways in wax biosynthesis. We propose that <i>OsGL1-6</i> is involved in the accumulation of leaf cuticular wax and directly impacts drought resistance in rice.</p>