Chen, Kegui , Valliyodan, Babu , Joshi, Trupti , Hejlek, Lindsey , LeNoble, Mary , Xu, Dong , Bohnert, Hans , Sharp, Robert , Nguyen, Henry .
Differential transcript regulation in the growth zone of the maize primary root during early stages of adaptation to water deficit.
A microarray study was conducted to address early responses of gene expression in the growth zone of the maize primary root after 5 h of water deficit. The growth zone was divided into two regions, Region 1 (R1, 0-3 mm from the apex) and Region 2 (R2, 3-7 mm). These regions were based on previous studies which showed that in roots which have adapted to water deficits, cell elongation rates are maintained in R1 but progressively inhibited in R2. Gene expression profiles showed more genes responding to water deficit in R2 than in R1. Down-regulation of many housekeeping, kinase, and 14-3-3 genes in R2 were consistent with growth suppression during the early phase of response to water stress. However, both R1 and R2 had begun to adapt to water stress within 5 h of stress imposition. R1 specific regulation of certain genes might be directly related to the growth maintenance of this region under water deficit, for example up-regulation of cell wall related genes (including two expansins and an XET) and carbonic metabolism genes regulating cell respiration (including two aconitate hydrates). The gene expression patterns were substantially different when compared with previous studies of longer duration water deficit (48h) in the same root regions, particularly for transcripts falling under the signaling category. Examples of region-specific and stress duration-specific regulation of kinases which may be involved in stress perception and response include receptor-like protein kinase ARK1 and pyruvate phosphate dikinase, which were expressed only in R1 at the early phase of water deficit. The genes regulated specifically in R2 reveal a complex signaling network of hormone and sugar sensing operating in adaptation to water deficit.
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1 - University of Missouri-Columbia, Division of Plant Sciences, 1-31 Agriculture Building, Columbia, MO, 65211, USA
2 - University of Missouri, Columbia, Division of Plant Sciences, 1-31 Ag Building, Columbia, MO, 65211, USA
3 - University of Missouri, Columbia, Department of Computer Science
4 - University of Illinois at Urbana-Champaign, Department of Crop Sciences
5 - University of Missouri-Columbia, Division of Plant Sciences
6 - University of Missouri, Columbia, Division of Plant Sciences
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM