Award details

Inositol hexakisphosphate as a key regulator of Nod factor induced calcium oscillations

Reference	BB/C513669/1
Principal Investigator / Supervisor	Professor Giles Oldroyd
Co-Investigators / Co-Supervisors	Dr Jongho Sun
Institution	John Innes Centre
Department	Disease and Stress Biology
Funding type	Research
Value (£)	190,150
Status	Completed
Type	Research Grant
Start date	01/06/2005
End date	31/05/2008
Duration	36 months

Abstract

Bacterial Nod factor is a central signalling molecule in the legume rhizobial symbiosis. One of the earliest plant responses to Nod factor is the activation of calcium spiking in root hair cells that appears to act as a signaltransduction component in this pathway. This work aims to define the mechanisms by which Nod factor perception can lead to activation of calcium spiking. Both inositol 1,4,5 trisphosphate and inositol hexakisphosphate have been shown to induce a cytosolic calcium flux in plant cells. We have shown that Nod factor induces an increase in inositol hexakisphosphate levels and transcriptionally activates an inositol phosphate kinase that is involved in the metabolic pathway leading to inositol hexakisphosphate. Furthermore, we have shown that inositol hexakisphosphate can induce calcium release in root hair cells, where Nod factor induced calcium spiking is observed. Our current hypotheses is that Nod factor induction of inositol hexakisphosphate leads to the activation of calcium spiking. In this proposal we expand upon these initial observations to further dissect the role that inositol hexakisphosphate plays in this signalling pathway. Specifically we will characterise in detail the Nod factor induction of inositol hexakisphosphate and place this induction in the context of proteins known to function in the Nod factor signalling pathway. Using caged molecules we will assess the calcium releasing capacity of inositol hexakisphosphate in root hair cells. In addition we will dissect inositol hexakisphosphate biosynthetic enzymes that play a role in Nod factor signalling, characterising their enzymatic activity and gene expression profiles. Proteins in this pathway that have the potential for interacting with Nod factor signalling will be targeted for gene knockout to assess their role in this signal transduction pathway. Finally we will assess using reverse genetics the effect of Phospholipase C on Nod factor induced inositol hexakisphate levels andadditional responses. We have already generated extensive evidence for a direct role for inositol hexakisphosphate in Nod factor induced calcium spiking and the work in this proposal is crucial to expand upon these exciting developments. Joint with BB/C514090/1.

Summary

unavailable

Committee	Closed Committee - Plant & Microbial Sciences (PMS)
Research Topics	Microbiology, Plant Science, Soil Science
Research Priority	X – Research Priority information not available
Research Initiative	X - not in an Initiative
Funding Scheme	X – not Funded via a specific Funding Scheme

Associated awards:

BB/C514090/1 Inositol hexakisphosphate as a key regulator of Nod factor induced calcium oscillations

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