title: Transgenic Arabidopsis flowers overexpressing acyl-CoA-binding protein ACBP6 are freezing tolerant.
abstract: Low temperature stress adversely affects plant growth. It has been shown that the overexpression of ACYL-COENZYME A-BINDING PROTEIN6 (ACBP6) resulted in enhanced freezing tolerance in seedlings and rosettes accompanied by a decrease in phosphatidylcholine (PC), an increase in phosphatidic acid (PA) and an up-regulation of PHOSPHOLIPASE Dδ(PLDδ) in the absence of COLD-RESPONSIVE (COR)-related gene induction. Unlike rosettes, ACBP6-overexpressor (OE) flowers showed elevations in PC and monogalactosyldiacylglycerol (MGDG) accompanied by a decline in PA. The increase in PC species corresponded to a decline in specific PAs. To better understand such differences, the expression of PC-, MGDG-, proline-, ABA- and COR-related genes, and their transcription factors [C-repeat binding factors (CBFs), INDUCER OF CBF EXPRESSION1 (ICE1) and MYB15] was analyzed by quantitative real-time PCR (qRT-PCR). ACBP6-conferred freezing-tolerant flowers showed induction of COR-related genes, CBF genes and ICE1, PC-related genes (PLDδ, CK, CK-LIKE1, CK-LIKE2, CCT1, CCT2, LPCAT1, PLA2α, PAT-PLA-IIβ, PAT-PLA-IIIα, PAT-PLA-IIIδ and PLDζ2), MGDG-related genes (MGD genes and SFR2) and ABA-responsive genes. In contrast, ACBP6-conferred freezing-tolerant rosettes were down-regulated in COR-related genes, CBF1, PC-related genes (PEAMT1, PEAMT2, PEAMT3, CK1, CCT1, CCT2, PLA2α, PAT-PLA-IIIδ and PLDζ2), MGDG-related genes (MGD2, MGD3 and SFR2) and some ABA-responsive genes including KIN1 and KIN2. These results suggest that the mechanism in ACBP6-conferred freezing tolerance varies in different organs.
authors.affiliation: School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China.
authors.forename: Pan
authors.initials: P
authors.lastname: Liao
authors.affiliation: School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, ChinaPresent address: 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: Qin-Fang
authors.initials: QF
authors.lastname: Chen
authors.affiliation: School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China mlchye@hkucc.hku.hk.
authors.forename: Mee-Len
authors.initials: ML
authors.lastname: Chye
mesh_terms: D000064:Acclimatization; D017360:Arabidopsis / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D035264:Flowers / Q000235:genetics / Q000502:physiology; D005615:Freezing; D018506:Gene Expression Regulation, Plant; D008055:Lipids / Q000032:analysis; D009928:Organ Specificity; D018515:Plant Leaves / Q000235:genetics / Q000502:physiology; D030821:Plants, Genetically Modified; D011392:Proline / Q000378:metabolism; D015854:Up-Regulation
chemical_list: C532782:ACBP6 protein, Arabidopsis; D029681:Arabidopsis Proteins; D002352:Carrier Proteins; D008055:Lipids; D011392:Proline
keywords: C-repeat binding factors; COR; Flowers; Monogalactosyldiacylglycerol; Phosphatidylcholine; Proline