Abstract
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 OsGL1-6 gene, a member of the fatty aldehyde decarbonylase gene family, is highly homologous to Arabidopsis CER1, which is involved in cuticular wax biosynthesis. However, whether OsGL1-6 participates in cuticular wax biosynthesis remains unknown. In this study, an OsGL1-6 antisense-RNA vector driven by its own promoter was constructed and introduced into the rice variety Zhonghua11 by Agrobacterium-mediated transformation to obtain several independent transgenic plants with decreased OsGL1-6 expression. These OsGL1-6 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 OsGL1-6 gene was constitutively expressed in all examined organs and was very highly expressed in leaf epidermal cells and vascular bundles. The transient expression of OsGL1-6-GFP 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 OsGL1-6 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 OsGL1-6 is associated with the decarbonylation pathways in wax biosynthesis. We propose that OsGL1-6 is involved in the accumulation of leaf cuticular wax and directly impacts drought resistance in rice.
Highlights
The cuticle is a continuous hydrophobic lipid layer structure that covers the exposed ground parts of terrestrial plants and forms a protective barrier against the external environment
The open reading frame (ORF) of OsGL1-6 is 1,908 bp, and it encodes a protein with 635 amino acids that has a molecular mass of 71.6 kD and an isoelectric point of 8.64 and that belongs to the fatty aldehyde decarbonylase superfamily
The treated leaves were subsequently analyzed using scanning electron microscopy (SEM) to examine the degree of cuticular extraction, and the results showed that the leaf cuticular wax layer was nearly invisible (Figure S4), indicating that the extraction was thorough
Summary
The cuticle is a continuous hydrophobic lipid layer structure that covers the exposed ground parts of terrestrial plants and forms a protective barrier against the external environment. The cuticular wax of all plants consists of derivatives of very long-chain fatty acid (VLCFAs) including alkanes, aldehydes, ketones, primary and secondary alcohols, and esters [9,10]. The biosynthesis of cuticular wax is accomplished by two steps: the fatty acid elongase-mediated extension of the C16 and C18 fatty acids to VLCFA chains and the conversion of each VLCFA to wax components by the decarbonylation and acyl reduction pathways in the endoplasmic reticulum (ER). The acyl reduction pathway mediates the production of primary alcohols and wax esters, whereas the decarbonylation process produces aldehydes, secondary alcohols, alkanes, and ketones [9,10]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
