Date of Award:

5-1-2004

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Biology

Committee Chair(s)

Daryll B. DeWald

Committee

Daryll B. DeWald

Committee

Gregory J. Podgorski

Committee

Noelle E. Cockett

Abstract

During dehydration and cold stress, Arabidopsis thaliana (A. thaliana) plant cells mobilize calcium into their cytosol to elicit changes in gene expression that enable them to tolerate stress. It has been unclear how dehydration-stressed plant cells receive and transmit the signal that results in promoting increases in intracellular calcium concentration. Previously, phosphatidylinositol 4,5-biphosphate (PtdIns(4,5)P2) and inositol 1,4,5 triphosphate (Ins(1,4,5)P3) have been shown to accumulate and cause calcium mobilization in osmotically stressed A. thaliana. However, it was unknown whether the same occurred in plants exposed to other abiotic stresses. Data presented in this thesis show that dehydration-stressed A. thaliana also accumulate PtdIns(4,5)P2 and Ins(1,4,5)P3, potentially leading to calcium mobilization. Although 1 h cold-stressed A. thaliana accumulate PtdIns(4,5)P2 in both shoot and root tissues with a large accumulation detected in root tissues, there was a reduction in the simultaneously measured Ins(1,4,5)P3 levels. In summary, these data show that PtdIns(4,5)P2 accumulates in dehydration and cold-stressed A. thaliana while Ins(1,4,5)P3 accumulates in dehydration-stressed plants. This suggests that the phosphoinositide signaling pathway is activated during dehydration and cold stress resulting in calcium mobilization.

Included in

Biology Commons

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