title: Three WRKY transcription factors additively repress abscisic acid and gibberellin signaling in aleurone cells.
abstract: Members of the WRKY transcription factor superfamily are essential for the regulation of many plant pathways. Functional redundancy due to duplications of WRKY transcription factors, however, complicates genetic analysis by allowing single-mutant plants to maintain wild-type phenotypes. Our analyses indicate that three group I WRKY genes, OsWRKY24, -53, and -70, act in a partially redundant manner. All three showed characteristics of typical WRKY transcription factors: each localized to nuclei and yeast one-hybrid assays indicated that they all bind to W-boxes, including those present in their own promoters. Quantitative real time-PCR (qRT-PCR) analyses indicated that the expression levels of the three WRKY genes varied in the different tissues tested. Particle bombardment-mediated transient expression analyses indicated that all three genes repress the GA and ABA signaling in a dosage-dependent manner. Combination of all three WRKY genes showed additive antagonism of ABA and GA signaling. These results suggest that these WRKY proteins function as negative transcriptional regulators of GA and ABA signaling. However, different combinations of these WRKY genes can lead to varied strengths in suppression of their targets.
authors.affiliation: School of Life Sciences, University of Nevada, Las Vegas, NV 89154, USA.
authors.forename: Liyuan
authors.initials: L
authors.lastname: Zhang
authors.affiliation: School of Life Sciences, University of Nevada, Las Vegas, NV 89154, USA.
authors.forename: Lingkun
authors.initials: L
authors.lastname: Gu
authors.affiliation: School of Life Sciences, University of Nevada, Las Vegas, NV 89154, USA.
authors.forename: Patricia
authors.initials: P
authors.lastname: Ringler
authors.affiliation: School of Life Sciences, University of Nevada, Las Vegas, NV 89154, USA.
authors.forename: Stanley
authors.initials: S
authors.lastname: Smith
authors.affiliation: Texas A&M AgriLife Research and Extension Center, Dallas, TX 75252, USA.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Rushton
authors.affiliation: School of Life Sciences, University of Nevada, Las Vegas, NV 89154, USA. Electronic address: jeffery.shen@unlv.edu.
authors.forename: Qingxi J
authors.initials: QJ
authors.lastname: Shen
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D056625:Endosperm / Q000254:growth & development / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D005875:Gibberellins / Q000378:metabolism*; D012275:Oryza / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D005875:Gibberellins; D010940:Plant Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; D000040:Abscisic Acid
keywords: Abscisic acid signaling; Gibberellin signaling; Oryza sativa; Rice; WRKY transcription factor