title: The roles of two transcription factors, ABI4 and CBFA, in ABA and plastid signalling and stress responses.
abstract: Genetic and physiological studies have revealed evidences for multiple signaling pathways by which the plastid exerts retrograde control over photosynthesis-associated-nuclear-genes. In this study we have examined the mechanisms of control of transcription by plastid signals, focusing on transcription factors. We have also further addressed the physical nature of plastid signals and the physiological role, in stress acclimation of this regulatory pathway. ABI4, a master Apetala 2 (AP2)-type transcription factor (TF), is targeted by multiple signalling pathways in plant cells, such as abscisic acid (ABA) signals, sugar signals and plastid signals derived from reactive oxygen species (ROS) and chlorophyll intermediates. ABI4 binds the promoter of target genes to prevent their transcription by competing with other competitive TFs. However, we found that once ABI4 bound the element (CCACGT), it may not be bound by other TFs, therefore making the signalling long-lasting. Downstream of ABI4, CBFA (CCAAT binding factor A) is a subunit of the HAP2/HAP3/HAP5 (Heme activator protein) trimeric transcription complex. CBFA however is a redundant HAP3 subunit. When emergency occurs (such as herbicide treatments or environmental stresses followed by ABA and ROS accumulation), the master transcription factor ABI4 down-regulates some TFs, like CBFA, and then some other TF subunits enter the transcription complex and transcriptional efficiency of stress-responsive genes (including the transcription co-factor CBP) is improved instantaneously. abi4, cbfA and cbp mutants showed weaker drought-tolerance after a herbicide norflurazon treatment, which indicated the physiological role of these key transcription factors.
authors.affiliation: College of Resources and Environmental Sciences, Sichuan Agricultural University, Chengdu, 611130, China.
authors.forename: Zhong-Wei
authors.initials: ZW
authors.lastname: Zhang
authors.forename: Ling-Yang
authors.initials: LY
authors.lastname: Feng
authors.forename: Jian
authors.initials: J
authors.lastname: Cheng
authors.forename: He
authors.initials: H
authors.lastname: Tang
authors.forename: Fei
authors.initials: F
authors.lastname: Xu
authors.forename: Feng
authors.initials: F
authors.lastname: Zhu
authors.forename: Zhong-Yi
authors.initials: ZY
authors.lastname: Zhao
authors.forename: Ming
authors.initials: M
authors.lastname: Yuan
authors.forename: Yang-Er
authors.initials: YE
authors.lastname: Chen
authors.forename: Jian-Hui
authors.initials: JH
authors.lastname: Wang
authors.forename: Shu
authors.initials: S
authors.lastname: Yuan
authors.forename: Hong-Hui
authors.initials: HH
authors.lastname: Lin
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D000222:Adaptation, Physiological; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D023081:CCAAT-Binding Factor / Q000235:genetics / Q000378:metabolism; D015536:Down-Regulation; D055864:Droughts; D018506:Gene Expression Regulation, Plant; D006427:Hemin / Q000494:pharmacology; D006540:Herbicides / Q000494:pharmacology; D016254:Mutagenesis, Insertional; D010937:Plant Growth Regulators / Q000378:metabolism*; D018515:Plant Leaves / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D030821:Plants, Genetically Modified; D018087:Plastids / Q000502:physiology; D011401:Promoter Regions, Genetic; D011724:Pyridazines / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D015398:Signal Transduction; D013312:Stress, Physiological; D015534:Trans-Activators; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: C470421:ABI4 protein, Arabidopsis; D029681:Arabidopsis Proteins; C584653:At4g14540 protein, Arabidopsis; D023081:CCAAT-Binding Factor; D006540:Herbicides; D010937:Plant Growth Regulators; D011724:Pyridazines; D017382:Reactive Oxygen Species; D015534:Trans-Activators; D014157:Transcription Factors; D000040:Abscisic Acid; D006427:Hemin; C008677:norflurazone