title: Arabidopsis acyl-CoA-binding protein ACBP3 participates in plant response to hypoxia by modulating very-long-chain fatty acid metabolism.
abstract: In Arabidopsis thaliana, acyl-CoA-binding proteins (ACBPs) are encoded by a family of six genes (ACBP1 to ACBP6), and are essential for diverse cellular activities. Recent investigations suggest that the membrane-anchored ACBPs are involved in oxygen sensing by sequestration of group VII ethylene-responsive factors under normoxia. Here, we demonstrate the involvement of Arabidopsis ACBP3 in hypoxic tolerance. ACBP3 transcription was remarkably induced following submergence under both dark (DS) and light (LS) conditions. 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. In contrast, suppression of ACBP3 in ACBP3-KOs enhanced plant tolerance to DS, LS and ethanol treatments. By analyses of double combinations of OE-1 with npr1-5, coi1-2, ein3-1 as well as ctr1-1 mutants, we observed that the attenuated hypoxic tolerance in ACBP3-OEs was dependent on NPR1- and CTR1-mediated signaling pathways. 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. By microscale thermophoresis analysis, the recombinant ACBP3 protein bound VLC acyl-CoA esters with high affinities in vitro. 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. Taken together, these findings suggest that Arabidopsis ACBP3 participates in plant response to hypoxia by modulating VLCFA metabolism.
authors.affiliation: State Key Laboratory of Biocontrol and Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China.
authors.forename: Li-Juan
authors.initials: LJ
authors.lastname: Xie
authors.forename: Lu-Jun
authors.initials: LJ
authors.lastname: Yu
authors.forename: Qin-Fang
authors.initials: QF
authors.lastname: Chen
authors.forename: Feng-Zhu
authors.initials: FZ
authors.lastname: Wang
authors.forename: Li
authors.initials: L
authors.lastname: Huang
authors.forename: Fan-Nv
authors.initials: FN
authors.lastname: Xia
authors.forename: Tian-Ren
authors.initials: TR
authors.lastname: Zhu
authors.forename: Jian-Xin
authors.initials: JX
authors.lastname: Wu
authors.forename: Jian
authors.initials: J
authors.lastname: Yin
authors.forename: Bin
authors.initials: B
authors.lastname: Liao
authors.forename: Nan
authors.initials: N
authors.lastname: Yao
authors.forename: Wensheng
authors.initials: W
authors.lastname: Shu
authors.forename: Shi
authors.initials: S
authors.lastname: Xiao
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D015687:Cell Hypoxia; D005227:Fatty Acids / Q000737:chemistry / Q000378:metabolism*; D013312:Stress, Physiological
chemical_list: C513212:ACBP3 protein, Arabidopsis; D029681:Arabidopsis Proteins; D002352:Carrier Proteins; D005227:Fatty Acids
keywords: Arabidopsis thaliana; acyl-CoA-binding proteins; hypoxic tolerance; sphingolipids; very-long-chain fatty acids