title: Molecular characterization of an ABA insensitive 5 orthologue in Brassica oleracea.
abstract: ABI5 (ABA insensitive 5), a bZIP (Basic leucine zipper) transcription factor, has been shown to be a major mediator of plant ABA responses during seed germination. Although the molecular basis of ABI5-modulated processes has been well demonstrated in Arabidopsis thaliana, its identity and function in cabbage (Brassica oleracea var. capitata L.) remain elusive. Here, we describe our identification of BolABI5 (an ABI5 orthologue in B.oleracea) as a functional bZIP transcription factor in the modulation of plant ABA responses. Expression of BolABI5 was dramatically induced by drought stress and exogenous ABA. Heterogeneous expression of BolABI5 rescued the insensitive phenotype of Arabidopsis abi5-1 to ABA during seed germination. Subcellular localization and trans-activation assays revealed that BolABI5 was localized in the nucleus and possessed DNA binding and trans-activation activities. Deletion of the bZIP domain generated BolABI5ΔbZIP, which no longer localized exclusively in the nucleus and had almost no detectable DNA-binding or trans-activation activities. Overall, these results suggest that BolABI5 may function as ABI5 in the positive regulation of plant ABA responses.
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas, College of Life Science, Northwest A&F University, Yangling, Shaanxi, China.
authors.forename: Xiaona
authors.initials: X
authors.lastname: Zhou
authors.forename: Feifei
authors.initials: F
authors.lastname: Yuan
authors.forename: Mengyao
authors.initials: M
authors.lastname: Wang
authors.forename: Aiguang
authors.initials: A
authors.lastname: Guo
authors.forename: Yanfeng
authors.initials: Y
authors.lastname: Zhang
authors.forename: Chang Gen
authors.initials: CG
authors.lastname: Xie
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D050976:Basic-Leucine Zipper Transcription Factors / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D001937:Brassica / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D035264:Flowers / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D018525:Germination; D010802:Phylogeny; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012639:Seeds / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D015533:Transcriptional Activation
chemical_list: D050976:Basic-Leucine Zipper Transcription Factors; D011993:Recombinant Fusion Proteins; D000040:Abscisic Acid