Unable to connect to database - 13:34:34 Unable to connect to database - 13:34:34 SQL Statement is null or not a SELECT - 13:34:34 SQL Statement is null or not a DELETE - 13:34:34 Botany & Plant Biology 2007 - Abstract Search
Unable to connect to database - 13:34:34 Unable to connect to database - 13:34:34 SQL Statement is null or not a SELECT - 13:34:34

Abstract Detail


Hormone Biology

Ramirez, Gustavo [1], Davis, John [1], Kirst, Matias [1].

Cytokinin Response Regulators in Populus: The As, Bs and Pseudos.

Cytokinins are plant hormones that influence diverse processes of growth and development. The cytokinin signaling pathway resembles bacterial and yeast two-component signal transduction pathways in which an external signal is perceived by a sensor protein and then transmitted in the form of a phosphate group to a response regulator (RR) protein. The Populus genome encodes 33 proteins with high sequence similarity to other plant and bacterial RRs. Further analysis of predicted amino acid sequences of this gene family revealed the presence of 11 type-As, 11 type-Bs and 11 pseudo-RRs. We generated gene expression data for most of the family members through whole-genome microarray analysis and semi-quantitative RT-PCR. Most of the type-As were expressed in roots and stems, however three closely related genes (PtRR8, PtRR9 and PtRR11) were  expressed in reproductive tissues. We detected expression of nine type-B RRs. Transcripts for most of the type-Bs were detected more or less ubiquitously in the organs tested, however expression was relatively high in nodes, phloem and roots. Pseudo-RRs were preferentially expressed in leaves. To evaluate the regulation of RRs by cytokinin, we treated detached leaves with cytokinin. Consistent with the Arabidopsis model in which type-As are involved in the primary response to cytokinin, seven of the type-As showed rapid transcript upregulation. In contrast to the Arabidopsis model in which type-B RRs are not regulated by cytokinin, transcripts levels for three type-Bs (PtRR13, PtRR18 and PtRR20) were also upregulated. This may indicate novel regulation of these genes in Populus. The identification of RRs and their cytokinin regulation in Populus sets the stage for their functional analysis via reverse genetics.


Log in to add this item to your schedule

1 - University of Florida, Plant Molecular and Cellular Biology, PO Box 110690, Gainesville, Florida, 32611, USA

Keywords:
Cytokinin
Populus
response regulators.

Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P35016
Abstract ID:313


Copyright © 2000-2007, Botanical Society of America. All rights