The gene encoding Arabidopsis acyl-CoA-binding protein 3 is pathogen inducible and subject to circadian regulation

• Published in: Journal of experimental botany Vol. 63; no. 8; pp. 2985 - 3000
• Main Authors: Zheng, Shu-Xiao, Xiao, Shi, Chye, Mee-Len
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01.05.2012
• Subjects: 5' Flanking Region; 5' Flanking Region - genetics; Arabidopsis; Arabidopsis - drug effects; Arabidopsis - genetics; Arabidopsis - growth & development; Arabidopsis - microbiology; Arabidopsis Proteins; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Arabidopsis thaliana; Base Sequence; binding proteins; Biological and medical sciences; Carrier Proteins; Carrier Proteins - genetics; Carrier Proteins - metabolism; Circadian Rhythm; Circadian Rhythm - drug effects; Circadian Rhythm - genetics; Darkness; deoxyribonuclease I; Deoxyribonuclease I - metabolism; DNA Footprinting; drug effects; electrophoresis; Electrophoretic Mobility Shift Assay; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Developmental; Gene Expression Regulation, Developmental - drug effects; Gene Expression Regulation, Plant; Gene Expression Regulation, Plant - drug effects; genes; Genes, Plant; Genes, Plant - genetics; genetics; Glucuronidase; Glucuronidase - metabolism; growth & development; leaf protein; leaves; Lycopersicon esculentum; metabolism; microbiology; Molecular Sequence Data; pathogens; pharmacology; physiology; Plant Growth Regulators; Plant Growth Regulators - pharmacology; Plant physiology and development; Pseudomonas syringae; Pseudomonas syringae - drug effects; Pseudomonas syringae - physiology; Pseudomonas syringae pv. tomato; Recombinant Fusion Proteins; Recombinant Fusion Proteins - metabolism; Regulatory Sequences, Nucleic Acid; Regulatory Sequences, Nucleic Acid - genetics; Reproducibility of Results; Research Papers; Sequence Analysis, DNA; Sequence Deletion; Sequence Deletion - genetics; stems; Time Factors; vascular bundles; Light effect; dark/light regulation; GT-1 cis-acting element; Acyl; Circadian rhythm; Defensive response; Arabidopsis thaliana; Arabidopsis ACBP3; Binding protein; defence response; Gene; Cruciferae; Dicotyledones; Pathogenic; S-box; Angiospermae; Botany; Regulatory sequence; Spermatophyta; Cis effect; Experimental plant; Dof-box; Photoregulation
• ISSN: 0022-0957; 1460-2431; 1460-2431
• DOI: 10.1093/jxb/ers009

In Arabidopsis thaliana, acyl-CoA-binding protein 3 ( ACBP3), one of six ACBPs, is unique in terms of the C-terminal location of its acyl-CoA-binding domain. It promotes autophagy-mediated leaf senescence and confers resistance to Pseudomonas syringae pv. tomato DC3000. To understand the regulation of ACBP3, a 1.7 kb 5'-flanking region of ACBP3 and its deletion derivatives were characterized using β-glucuronidase (GUS) fusions. A 374 bp minimal fragment (-151/+223) could drive GUS expression while a 1698 bp fragment (-1475/+223) conferred maximal activity. Further, histochemical analysis on transgenic Arabidopsis harbouring the largest (1698 bp) ACBP3pro::GUS fusion displayed ubiquitous expression in floral organs and vegetative tissues (vascular bundles of leaves and stems), consistent with previous results showing that extracellularly localized ACBP3 functions in plant defence. A 160 bp region (-434/-274) induced expression in extended darkness and caused down-regulation in extended light. Electrophoretic mobility shift assay (EMSA) and DNase I footprinting assay showed that the DNA-binding with one finger box (Dof-box, -341/-338) interacted specifically with leaf nuclear proteins from dark-treated Arabidopsis, while GT-1 (-406/-401) binds both dark- and light-treated Arabidopsis, suggesting that Dof and GT-1 motifs are required to mediate circadian regulation of ACBP3. Moreover, GUS staining and fluorometric measurements revealed that a 109 bp region (-543/-434) was responsive to phytohormones and pathogens. An S-box of AT-rich sequence (-516/-512) was identified to bind nuclear proteins from pathogen-infected Arabidopsis leaves, providing the basis for pathogen-inducible regulation of ACBP3 expression. Thus, three cis-responsive elements (Dof, GT-1, and the S-box) in the 5'-flanking region of ACBP3 are proven functional in the regulation of ACBP3.