Arabidopsis KCS5 and KCS6 Play Redundant Roles in Wax Synthesis

Abstract

3-ketoacyl-CoA synthases (KCSs), as components of a fatty acid elongase (FAE) complex, play key roles in determining the chain length of very-long-chain fatty acids (VLCFAs). KCS6, taking a predominate role during the elongation from C26 to C28, is well known to play an important role in wax synthesis. KCS5 is one paralog of KCS6 and its role in wax synthesis remains unknown. Wax phenotype analysis showed that in kcs5 mutants, the total amounts of wax components derived from carbon 32 (C32) and C34 were apparently decreased in leaves, and those of C26 to C32 derivatives were obviously decreased in flowers. Heterologous yeast expression analysis showed that KCS5 alone displayed specificity towards C24 to C28 acids, and its coordination with CER2 and CER26 catalyzed the elongation of acids exceeding C28, especially displaying higher activity towards C28 acids than KCS6. BiLC experiments identified that KCS5 physically interacts with CER2 and CER26. Wax phenotype analysis of different organs in kcs5 and kcs6 single or double mutants showed that KCS6 mutation causes greater effects on the wax synthesis than KCS5 mutation in the tested organs, and simultaneous repression of both protein activities caused additive effects, suggesting that during the wax biosynthesis process, KCS5 and KCS6 play redundant roles, among which KCS6 plays a major role. In addition, simultaneous mutations of two genes nearly block drought-induced wax production, indicating that the reactions catalyzed by KCS5 and KCS6 play a critical role in the wax biosynthesis in response to drought.

BrWAX3, encoding a β-ketoacyl-CoA synthase, participates in cuticular wax biosynthesis in Chinese cabbage

“…(5) Subcellular localization analysis showed that the BrCER60.A09was localized to the ER, which is the site of wax biosynthesis. (6) Cuticular wax composition analysis showed a reduction of wax monomers with chain lengths beyond C26 and an increased proportion of shorter chains, which was in agreement with the CER60 function in Arabidopsis (Huang et al 2022). Overall, the 5,567-bp insertion of BrCER60.A09 in SD369 was the main cause of the glossy phenotype.…”

“…The cer6 mutant showed a substantial reduction of derivatives beyond C26, and nearly abolished stem wax accumulation, and exhibited conditional male sterility (Fiebig et al 2000;Hooker et al 2002;Huang et al 2022;Millar et al 1999). CER60/KCS5, a paralog of CER6/KCS6, play a redundant role with CER6/KCS6 in wax biosynthesis, but CER6/KCS6 plays a major role (Huang et al 2022). The mutation in CER60/KCS5 caused only a slight reduction in total wax amounts in leaves and owers, and the wax amounts in stems barely changed (Huang et al 2022).…”

Toxicity of Bacillus thuringiensis Strains Derived from the Novel Crystal Protein Cry31Aa with High Nematicidal Activity against Rice Parasitic Nematode Aphelenchoides besseyi

“…Furthermore, Bacillus spp. and its products have been shown to stimulate the plant immune response and induce systemic resistance (ISR) and upregulate the pathogenicity-related genes in plants [ 55 , 56 ]. The rapid buildup of H 2 O 2 is considered to be a significant phytopathogen defense signal in cellular plants [ 57 ].…”

Ziziphus nummularia: A Comprehensive Review of Its Phytochemical Constituents and Pharmacological Properties

“…In the wake of climate change, drought has become a calamitous abiotic stress, affecting plant growth and hampering agricultural production and yield. The economic impact of this stress is likely to increase further; as a result, there has been growing interest in studying drought stress responses and tolerance mechanisms of natural drought-tolerant plants [48], such as Ziziphus nummularia. The purpose will be to develop crops with increased tolerance and resilience to drought.…”