Arabidopsis acyl-CoA-binding protein ACBP3 participates in plant response to hypoxia by modulating very-long-chain fatty acid metabolism.
Bottom Line: ACBP3-overexpressors (ACBP3-OEs) showed hypersensitivity to DS, LS and ethanolic stresses, with reduced transcription of hypoxia-responsive genes as well as accumulation of hydrogen peroxide in the rosettes.Lipid profiling revealed that both the total amounts and very-long-chain species of phosphatidylserine (C42:2- and C42:3-PS) and glucosylinositolphosphorylceramides (C22:0-, C22:1-, C24:0-, C24:1-, and C26:1-GIPC) were significantly lower in ACBP3-OEs but increased in ACBP3-KOs upon LS exposure.Further, a knockout mutant of MYB30, a master regulator of very-long-chain fatty acid (VLCFA) biosynthesis, exhibited enhanced sensitivities to LS and ethanolic stresses, phenotypes that were ameliorated by ACBP3-RNAi.
Affiliation: State Key Laboratory of Biocontrol and Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China.Show MeSH
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Mentions: To investigate the potential role of ACBP3 in regulating lipid metabolism during hypoxia, lipid profiles of Arabidopsis rosettes following LS exposure were analyzed. Under normal growth conditions, few differences were detected between wild type and ACBP3-OEs or ACBP3-KOs except that the levels of phosphatidylserine (PS) increased significantly in ACBP3-OEs (Figure 7a). When specific lipid species were analyzed, the levels of C34:3-, C34:2-, C34:1-, C36:5-, C38:3-, C40:3- and C42:3-PS were significantly higher in both OE-1 and OE-4 lines compared with wild type (Figure 7b, upper graph). After a 4-day LS treatment, total phosphatidylinositol (PI), PS and phosphatidic acid (PA) levels were significantly elevated in wild-type rosettes, while the levels of other lipids remained unchanged (Figure 7a). In contrast, galactolipids, including digalactosyldiacylglycerol (DGDG) and monogalactosyldiacylglycerol (MGDG), as well as phospholipids such as phosphatidylglycerol (PG), PC, PE and PI, declined in wild-type rosettes but PA levels showed significant elevation compared to the untreated control (Figure 7a). In particular, more significant changes were observed in the membrane lipid content between wild-type and ACBP3-OE rosettes after LS treatment for 4 days, and between wild-type and ACBP3-KOs rosettes after LS treatment for 6 days (Figure 7a). Specifically, total levels of MGDG, DGDG, PG, PC, PI, PS and PA were significantly lower in the rosettes of ACBP3-OEs compared to those of wild type under 4-day LS stress, while most of these lipid molecules were remarkably higher in the rosettes of ACBP3-KOs than that of 6-day LS-treated wild type (Figure 7a). These data are consistent with increased hypoxia sensitivity in ACBP3-OEs but increased tolerance in ACBP3-KOs.
Affiliation: State Key Laboratory of Biocontrol and Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China.