Source: RESEARCH FOUNDATION OF THE CITY UNIVERSITY OF NEW YORK submitted to NRP
TRANSCIPTIONAL REGULATION IN ROP10 GTPASE-MEDIATED ABA SIGNALING
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
NRI COMPETITIVE GRANT
Reporting Frequency
Annual
Accession No.
0200731
Grant No.
2004-35304-14911
Cumulative Award Amt.
$99,896.00
Proposal No.
2004-03459
Multistate No.
(N/A)
Project Start Date
Sep 1, 2004
Project End Date
Aug 31, 2006
Grant Year
2004
Program Code
[53.0]- (N/A)
Recipient Organization
RESEARCH FOUNDATION OF THE CITY UNIVERSITY OF NEW YORK
230 W 41ST STREET FL 7
NEW YORK,NY 10036-7207
Performing Department
(N/A)
Non Technical Summary
Abscisic acid (ABA) is an important hormone that modulates a variety of agronomically important developmental processes and stress responses. However, it remains unknown how ABA signal is perceived and transmitted to the nucleus. ROP10 small GTPase has been shown to be a negative regulator of ABA signal transduction and to suppress MYB2 expression, but its downstream targets have not been identified. This project will investigate transcriptional regulation of ABA signal transduction by ROP10. Specifically, this project plans to determine whether MYB and MYC transcription factors are the downstream transcriptional effectors of ROP10 signaling using molecular, genomic and genetic approaches. The mechanistic understanding of ROP10 signaling in ABA responses in the model plant Arabidopsis will provide insights into ABA signaling in crop systems and therefore this project will provide the basis for increasing crop production.
Animal Health Component
(N/A)
Research Effort Categories
Basic
100%
Applied
(N/A)
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
20624201030100%
Knowledge Area
206 - Basic Plant Biology;

Subject Of Investigation
2420 - Noncrop plant research;

Field Of Science
1030 - Cellular biology;
Goals / Objectives
To investigate transcriptional regulation by the plasma membrane-localized ROP10 small GTPase in abscisic acid (ABA) signal transduction in Arabidopsis. The specific objectives of this project are: (1) to investigate which MYB and MYC transcription factors are transcriptionally regulated in ROP10-mediated ABA signaling; and (2) to determine which MYB and MYC transcription factors are downstream targets of ROP10.
Project Methods
Molecular, genomic and genetic approaches will be used to study transcriptional regulation in ROP10-mediated ABA signaling. Specifically, we will (1) study mRNA expression patterns of MYB2 and MYC2 and theirs closely related genes in the rop10 mutant background, (2) use DNA microarray to investigate transcriptome in rop10; (3) study epigenetic relationships between rop10 and myb/myc knockout mutants.

Progress 09/01/04 to 08/31/05

Outputs
During this period, we determined using RT-PCR that MYB112 exhibited a similar ABA-induced, ROP10-suppressed response pattern as MYB2. Other MYB2- or MYC2-related transcription factors did not exhibit such expression pattern. Through transcriptome analysis, we then revealed that ROP10 gates the expression of a particular subset of genes that are specific to low concentrations of ABA. Most of these genes encode regulatory proteins such as receptor-like kinases, ATPases, GNAT family acetyltransferase and zinc finger proteins. These results have been published in the November issue of Plant Physiology. We also obtained knockout mutants of MYB2, MYB112 and MYC2 and transgenic plants expressing dominant negative forms of MYB2 and MYB112. Double mutants of various combinations of myb2, myc2 and rop10-1 have been constructed, and the homozygous triple mutant rop10-1 myb2 myc2 is in the selection process. myb112 was also crossed to rop10-1 myb2 to determine the possibility for the functional redundancy of MYB2 and MYB112 in effecting gene expression that is controlled by ROP10. In addition, transgenic plants overexpressing dominant negative forms of MYB2 and MYB112 have been obtained.

Impacts
The identification of a particular subset of the ROP10-gated, low ABA-specific genes will provide novel insights into the complex ABA signaling problem. This regulatory mechanism may enable plants to distinguish low versus high magnitudes and/or transient versus sustained change sin ABA levels or stress status. Interestingly, these genes were also shown to be involved in various abiotic and biotic responses. Therefore, the understanding of the gating by ROP10 of these genes in response to ABA might help improve crop resistance to a wide avariety of abiotic and biotic stresses.

Publications

  • Xin Z, Zhao Y and Zheng Z-L (2005) Transcriptome analysis reveals specific modulation of abscisic acid signaling by ROP10 small GTPase in Arabidopsis. Plant Physiology 139: 1350-1365