Yendrek, Craig R. , Harris, Jeanne M. .
Dissecting the roles of ABA, JA and ethylene in early Nod factor signaling events in Medicago truncatula.
Medicago truncatula is a legume that is able to form a symbiotic relationship with the nitrogen fixing soil bacterium Sinorhizobium meliloti. This interaction leads to the development of the nodule, a novel organ on the roots that encapsulates the bacteria and allows for the transport of fixed nitrogen into the plant. Prior to nodule initiation, the perception of a bacterially produced signal molecule called Nod factor leads to rapid changes in gene expression within the root transcriptome. The hormones abscisic acid (ABA), jasmonic acid (JA) and ethylene have all been shown to play a role in regulating the signaling initiated by Nod factor, as exogenous application of each will inhibit nodule initiation. In addition, a mutation in the SICKLE (SKL) locus, which confers ethylene insensitivity, results in a hypernodulation phenotype. Currently, a model exists to explain how JA and ethylene interact to modulate Nod factor signaling. However, it is important to further characterize this signaling network to include the effect of ABA. Here, we are using quantitative RT-PCR to examine the effect of altering the ABA and/or ethylene status of the plant on the expression of rhizobium-induced genes such as RHIZOBIUM INDUCED PEROXIDASE 1 (RIP1) and EARLY NODULIN 40 (ENOD40), as well as the ABA-responsive gene ABA RESPONSIVE ELEMENT BINDING FACTOR 1 (AREB1). Using these molecular tools, we hope to further refine the model of Nod factor signaling to include these new aspects of hormone crosstalk.
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1 - University of Vermont, Plant Biology, 109 Carrigan Drive, 120 Marsh Life Science Building, Burlington, VT, 05405, USA
2 - University of Vermont, Plant Biology
Nod factor signaling
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM