Wax Crystal-Sparse Leaf1 encodes a beta-ketoacyl CoA synthase involved in biosynthesis of cuticular
June 27th, 2008 | by admin |Wax Crystal-Sparse Leaf1 encodes a beta-ketoacyl CoA synthase involved in biosynthesis of cuticular waxes on rice leaf.
Cuticular waxes, forming the plant/atmosphere interface of plants colonizing the terrestrial environment, are complex mixtures of very-long chain fatty acids (VLCFAs) and their derivatives. In VLCFAs biosynthesis, beta-ketoacyl CoA synthase (E.C.2.3.1.119, KCS) is the key enzyme. Using T-DNA insertional mutagenesis, we identified a cuticle-deficient rice mutant, which displayed a pleiotropic phenotype including reduced growth, leaf fusion, sparse wax crystals, enhanced sensitivity to drought and low fertility. Further analysis indicated that T-DNA was inserted in the 5\’-UTR intron of the affected gene, Wax Crystal-Sparse Leaf1 (WSL1), and abnormal transcript caused the loss-of-function of WSL1 gene. Genetic complementation experiment confirmed the function of the candidate gene. WSL1 was predicted to encode a polypeptide containing a conserved FAE1_CUT1_RppA domain typical of the KCS family proteins. Qualitative and quantitative wax composition analyses by gas chromatography-mass spectrometry (GC-MS) demonstrated a marked reduction of total cuticular wax load on wsl1 leaf blades and sheaths, and VLCFA precursors of C20-C24 decreased in both. Moreover, ubiquitous expression of the WSL1 gene gave a hint that WSL1-catalyzed elongation of VLCFAs might participate in a wide range of rice growth and development processes beyond biosynthesis of cuticular waxes.
Yu D, Ranathunge K, Huang H, Pei Z, Franke R, Schreiber L, He C.
State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, 100101, Beijing, People’s Republic of China.