Ectopic Expression of CsKCS6 From Navel Orange Promotes the Production of Very-Long-Chain Fatty Acids (VLCFAs) and Increases the Abiotic Stress Tolerance of Arabidopsis thaliana

Abstract

Cuticular wax is closely related to plant resistance to abiotic stress. 3-Ketoacyl-CoA synthase (KCS) catalyzes the biosynthesis of very-long-chain fatty acid (VLCFA) wax precursors. In this study, a novel KCS family gene was isolated from Newhall navel orange and subsequently named CsKCS6 . The CsKCS6 protein has two main domains that belong to the thiolase-like superfamily, the FAE1-CUT1-RppA and ACP_syn_III_C domains, which exist at amino acid positions 80–368 and 384–466, respectively. CsKCS6 was expressed in all tissues, with the highest expression detected in the stigma; in addition, the transcription of CsKCS6 was changed in response to drought stress, salt stress and abscisic acid (ABA) treatment. Heterologous expression of CsKCS6 in Arabidopsis significantly increased the amount of VLCFAs in the cuticular wax on the stems and leaves, but there were no significant changes in total wax content. Compared with that of the wild-type (WT) plants, the leaf permeability of the transgenic plants was lower. Further research showed that, compared with the WT plants, the transgenic lines experienced less water loss and ion leakage after dehydration stress, displayed increased survival under drought stress treatment and presented significantly longer root lengths and survival under salt stress treatment. Our results indicate that CsKCS6 not only plays an important role in the synthesis of fatty acid precursors involved in wax synthesis but also enhances the tolerance of transgenic Arabidopsis plants to abiotic stress. Thus, the identification of CsKSC6 could help to increase the abiotic stress tolerance of Citrus in future breeding programs.

Identification and Structure Analysis of KCS Family Genes Suggest Their Reponding to Regulate Fiber Development in Long-Staple Cotton Under Salt-Alkaline Stress

“…CsKCS6 was essential in the synthesis of fatty acid precursors involved in wax synthesis, and it also enhanced the tolerance of transgenic Arabidopsis to drought and salt stress (Guo et al, 2020). In our results, some KCS genes of G. barbadense responded to salt-alkaline stress (Figure 5C).…”

Elucidating the Molecular Mechanisms by which Seed-Borne Endophytic Fungi, Epichloë gansuensis, Increases the Tolerance of Achnatherum inebrians to NaCl Stress

“…The wax biosynthetic process, flavonoid biosynthetic process, long-chain fatty acid metabolic process and oxidation-reduction process were down-regulated by E. gansuensis at 0 mM NaCl. Long-chain fatty acids are imperative to plant survival and have various functions throughout each period of plant growth and development [76,77]. Wax and cutin, as the derivative of long-chain fatty acids, are synthesized in a specific cell [76], therefore, wax and cutin decrease with the decrease in long-chain fatty acids.…”

Transcriptomics of developing wild sunflower seeds from the extreme ends of a latitudinal gradient differing in seed oil composition

“…KCS genes are involved in the elongation step during the synthesis of very-long-chain fatty acids (Gu et al, 2020a; Millar and Kunst, 1997). Drought stress is known to trigger production of these very-long-chain fatty acids, and while they don’t affect the overall degree of seed oil saturation, expression of these genes can alter the levels of individual fatty acids within seed oils (Gu et al, 2020a; Guo et al, 2020; Hashim et al, 1993). Members of the ALA-ALIS flippase complex are also differentially expressed and are involved in the translocation of phospholipids between membrane bilayers (Nintemann et al, 2019).…”