Poster: Signaling, cell-to-cell
Abs #
440: A Functional Genomics Approach for Understanding Inositol Phosphate and Phosphatidylinositol Phosphate Breakdown in Plants.
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Presenter: |
Gillaspy, Glenda , gillaspy@vt.edu |
Authors | Ercetin, Mustafa (A) Gunesekera, Bhadra (A) Burnette, Ryan (A) Kanter, Diane (A) Robinson, Jamille (A) Gillaspy, Glenda (A) | | Affiliations: |
(A): Virginia Tech
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Inositol phosphate (IP) and phosphatidylinositol phosphate (PIP) molecules are involved in various signal transduction pathways in many different organisms. IPs and PIPs that contain a 5-phosphate are hydrolyzed by a group of enzymes named inositol 5-phosphatases (5PTases). We are interested in how plants control the accumulation of IPs and PIPs, including I(1,4,5)P3 and PI(4,5)P2, and whether manipulation of 5PTases could alter signal transduction in plants. To answer this, we are investigating 15 genes from Arabidopsis that encode 5PTases. Expression analysis indicates that plants regulate expression of 5PTases in response to signaling, effectively linking signal termination to second messenger generation. Phylogenetic analysis of the 15 At5PTases predicts 2 types of enzymes, differing at their N-termini by the absence/presence of a WD repeat region. Expression of several different recombinant At5PTases in a Drosophila expression system shows that the At5PTase proteins differ in substrate specificity. We are examining gain-of-function and loss-of-function mutants to determine the effects on plant growth and signaling. We previously reported that ectopic expression of At5PTase1 results in lower IP3 levels and blocks ABA signaling. We will report our results on an At5PTase1 knock-out mutant that also has altered IP3 levels and ABA responses. We are also testing the response of the At5PTase1 knock-out mutant to other biotic and abiotic stimuli. Together, these experiments will allow us to identify pathways utilizing various IP and PIP signaling molecules and to determine whether the At5PTase genes may be used to confer beneficial signaling traits.
