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Series GSE9341 Query DataSets for GSE9341
Status Public on Mar 01, 2008
Title Gene expression in Maize root region 1 at low water potential
Organism Zea mays
Experiment type Expression profiling by array
Summary Previous work showed that the maize primary root adapts to low water potential (-1.6 MPa) by maintaining longitudinal expansion in the apical 3 mm (region 1), whereas in the adjacent 4 mm (region 2) longitudinal expansion reaches a maximum in well-watered roots but is progressively inhibited at low water potential. To identify mechanisms that determine these responses to low water potential, transcript expression was profiled in these regions of water-stressed and well-watered roots. In addition, comparison between region 2 of water-stressed roots and the zone of growth deceleration in well-watered roots (region 3) distinguished stress-responsive genes in region 2 from those involved in cell maturation. Responses of gene expression to water stress in regions 1 and 2 were largely distinct. The largest functional categories of differentially expressed transcripts were reactive oxygen species and carbon metabolism in region 1, and membrane transport in region 2. Transcripts controlling sucrose hydrolysis distinguished well-watered and water-stressed states (invertase vs. sucrose synthase), and changes in expression of transcripts for starch synthesis indicated further alteration in carbon metabolism under water deficit. A role for inositols in the stress response was suggested, as was control of proline metabolism. Increased expression of transcripts for wall-loosening proteins in region 1, and for elements of ABA and ethylene signaling were also indicated in the response to water deficit. The analysis indicates that fundamentally different signaling and metabolic response mechanisms are involved in the response to water stress in different regions of the maize primary root elongation zone.
Keywords: water stress response, root growth
Overall design Three pair-wise comparisons were made of transcripts from water-stressed and well-watered tissues in the different root tip regions. In the first comparison (C1), transcripts from region 1 of water-stressed seedlings were compared with those from region 1 of well-watered seedlings. The second comparison (C2) was made between transcripts from region 2 of the two treatments. We expected a larger number of genes to be differentially expressed in region 2 because its elongation rate decreased greatly under water-stressed compared with well-watered conditions. To prioritize the differentially expressed genes revealed in this comparison, a distinction was made between those genes that are associated with growth inhibition in region 2 specifically as a response to water stress, and those genes that are involved in root cell maturation whether under stress or control conditions. A hypothetical example of the former might be genes involved in auxin response since water stress can increase maize root auxin content [8] and application of exogenous auxin can shorten the root growth zone [9]. An example of the latter might involve genes for secondary wall synthesis, e.g., [10]. To experimentally make this distinction a third pair-wise comparison (C2/3) was included to compare expression of genes between water-stressed region 2 and well-watered region 3 as these are both regions of cell maturation. Genes differentially expressed in both C2 and C2/3 are more likely to cause growth inhibition at low water potential and are not likely to be part of the maturation program itself, whereas genes differentially expressed only in C2 are more likely related to maturation.
Four biological replicates were included each with dye-swap. The maize oligonucleotide array comes in two slides, A and B. Thus for each of the three comparisons made there were 16 slides (4 biological reps, 2 for dye-swap, 2 parts to an array).
Contributor(s) Spollen WG, Tao W, Valliyodan B, Chen K, Hejlek LG, Kim J, LeNoble ME, Zhu J, Bohnert HJ, Henderson D, Schachtman DP, Davis GE, Springer GK, Sharp RE, Nguyen HT
Citation(s) 18387193
Submission date Oct 16, 2007
Last update date Mar 19, 2012
Contact name William G. Spollen
Phone 573-884-8151
Organization name University of Missouri-Columbia
Department Informatics Research Core Facility
Lab Scott A. Givan
Street address 113 Bond Life Sciences Center
City Columbia
State/province MO
ZIP/Postal code 65211
Country USA
Platforms (2)
GPL1990 Maize oligo array version 1.2 array A
GPL1991 Maize oligo array version 1.2 array B
Samples (16)
GSM237686 maize_root_region1_ws-ww_rep1-slideA
GSM237689 maize_root_region1_ww-ws_rep1-slideA
GSM237690 maize_root_region1_ws-ww_rep2-slideA
This SubSeries is part of SuperSeries:
GSE9379 Gene expression in Maize root
BioProject PRJNA105263

Download family Format
SOFT formatted family file(s) SOFTHelp
MINiML formatted family file(s) MINiMLHelp
Series Matrix File(s) TXTHelp

Supplementary file Size Download File type/resource
GSE9341_RAW.tar 55.3 Mb (http)(custom) TAR (of GPR)
Processed data included within Sample table

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