OsGL1-6 is involved in the accumulation of leaf cuticular wax and directly impacts drought resistance in rice. Genetic modification of OsGL1-6 may have great potential for improving the drought resistance of rice.
Antisense-RNA Transgenic Plants:
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. Analysis of the GUS activity showed that it was detected in the calli, roots, stems, leaves and spikelets at different developmental stages. Although the expression of OsGL1-6 had tissue and developmental stage specificity, most of it was localized in the epidermal cells and vascular bundle area.
- 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.
- The OsGL1-6 gene showed high expression in germinating seeds (72 h after imbibitions) and shoot (seedling with two tillers).
- OsGL1-6 was induced by drought, the OsGL1-6 showed strong induction only at 2 day after treatment. OsGL1-6 was induced by salt stress The expression level of OsGL1-6 peaked at 6 h after treatment and then decreased. With cold treatment, OsGL1-1 and OsGL1-4 showed strong induction at both 12 and 24 h after treatment, whereas OsGL1-6 showed high expression at 12 h but dramatically decreased expression at 24 h.
The transient expression of OsGL1-6-GFP fusion indicated that OsGL1-6 is localized in the endoplasmic reticulum (ER).
- OsGL1-6 is present on chromosome 2 of the rice genome and contains nine exons and eight introns (Figure 1A). The full length of OsGL1-6 cDNA is 2,218 bp. The 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.
- OsGL1-6 showed high sequence similarities with the identified numbers of the fatty aldehyde decarbonylase superfamily. OsGL1-6 has 53% sequence identity with CER1 and 33% homology with CER3/WAX2/YRE/FLP in Arabidopsis, 53% with Wda1, 33% with OsGL1-1, and 30% with OsGL1-2 in rice, and 33% with GL1 in maize.
- Phylogenic analysis of the predicted protein sequences for the six characterized genes with high similarities to OsGL1-6 showed that they can be grouped into two clades (Figure 1B). OsGL1-6 groups with WDA1 and CER1, whereas OsGL1-1, OsGL1-2, maize GL1, and WAX2 form the other group.
The outermost surfaces of plants are covered with an epicuticular wax layer that provides a primary waterproof barrier and protection against different environmental stresses. Glossy 1 (GL1) is one of the reported genes controlling wax synthesis.
Labs working on this gene
- Laboratory Center of Basic Biology and Biotechnology, Education Department of Guangdong Province, College of Life Sciences, Zhongkai University of Agriculture and Engineering, Guangzhou, Guangdong, People’s Republic of China
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, People’s Republic of China
- College of Agronomy, Northwest A&F University, Yangling, Shanxi, People’s Republic of China
- Zhou L, Ni E, Yang J, et al. Rice OsGL1-6 is involved in leaf cuticular wax accumulation and drought resistance[J]. PloS one, 2013, 8(5): e65139.
- Islam M A, Du H, Ning J, et al. Characterization of Glossy1-homologous genes in rice involved in leaf wax accumulation and drought resistance[J]. Plant molecular biology, 2009, 70(4): 443-456.