Jaradat, Masrur R. , Huang, Daiqing , Cutler, Adrian J. .
Functional characterization of the transcription factor AtMYBR1 – a repressor of ABA signaling.
The phytohormone abscisic acid (ABA) mediates various physiological responses including seed storage product accumulation, seed dormancy, seed germination and responses to stresses such as drought, salinity, osmotic and cold. Previously, we identified the transcription factor AtMYBR1 as an ABA-regulated gene in a microarray analysis of Arabidopsis gene expression using a hyperactive ABA analog, (+)-8’ acetylene ABA (PBI425), that enhances expression of ABA responsive genes (Huang et al, 2007, Plant Journal. In Press). We report here that AtMYBR1 represses responses to ABA. Seeds over-expressing MYBR1 (OxMYBR1) were insensitive to ABA during germination and rosette leaves of OxMYBR1 lost water faster than those of wild type. Microarrays were used to profile transcripts in WT, OxMYBR1 and mybr1 plants in the presence and absence of PBI425. In OxMYBR1 plants, expression of many ABA-related genes including COR15a, COR15b, COR47, KIN2, ERD4, P5CS1 and FL3-5A3 were reduced in OxMYBR1 plants compared to wild type plants.
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1 - The National Research Council of Canada, Plant Biotechnology Institute, NRC-PBI, 110 Gymnasium Place, Saskatoon, Saskatchewan, S7N0W9, Canada
2 - The National Research Council of Canada, Plant Biotechnology Institute
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM