Our research involves studying the molecules which allow plant cells to respond to signals. Specifically, my lab is focusing on inositol phosphatases that can hydrolyze the second messenger inositol triphosphate (IP3), which many organisms use to respond to various signals. For example, plants may respond to the presence of light or a change in gravity by initiating the rapid synthesis of IP3 which then triggers the release of intracellular calcium in the cell. To stop this signaling process, IP3 must be made inactive by sequential removal of its three phosphate groups. We have cloned the genes encoding two of these phosphatases and are working on isolating the genes for the third. To gain a better understanding of how plants use IP3 in signaling we have constructed transgenic plants which have altered levels of the inositol phosphatases and presumably of IP3 levels as well. Based on their growth and development, we hypothesize that these plants are altered in their signaling responses, and are testing this hypothesis. This work is exciting in that IP3, as a common component of signaling, is an excellent target for manipulating signals from a variety of pathways. For example, we may be able to modulate responses of plants to light, or to affect other pathways such as disease resistance, fertility pathways and hormone perception.

A second area of work we are pursuing has direct implications for agricultural biotechnology. Due to agriculture run-off and other contaminants, our land becomes more saline each year. Thus, it is of increasing importance to understand how certain plants cope with this stress, and, if possible, to equip agronomically important plants with the ability to withstand such stresses. Accumulation of certain carbohydrates in plant cells such as inositol has been previously linked to beneficial qualities such as salt tolerance. Thus, we are currently trying to alter inositol levels in plant cells genetically. Because we now have the two genes which encode the enzymes required in inositol synthesis, we can use these genes to engineer plants capable of producing large amounts of inositol. We hope that increased inositol levels will lead to stability of plants in saline environments, and possibly to drought and cold tolerance as well.

Burnette, R. N., Gunesekera, B., and Gillaspy, G. (2003) An Arabidopsis Inositol 5-Phosphatase Gain-of-Function Alters Abscisic Acid Signaling. Plant Physiol. 132:1011-19.   [Abstract]

Styer, J., Spence, J., Keddie, J., and Gillaspy, G. (2004) Genomic Organization and Regulation of the LeIMP-1 and LeIMP-2 Genes Encoding myo-inositol Monophosphatase in Tomato. Gene 326:35-41.   [Abstract]

Ercetin, M. E. and Gillaspy, G. E. (2004) Molecular Characterization of an Arabidopsis Phospholipid-Specific Inositol Polyphosphate 5-Phosphatase. Plant Physiol., in press.   [Abstract]

Styer, J. C., Keddie, J., Spence, J., and Gillaspy, G. E. (2004) Genomic organization and regulation of the LeIMP-1 and LeIMP-2 genes encoding myo-inositol monophosphatase in tomato. Gene 326:35-41.   [Abstract]

Burnette RN, Gunesekera BM, Gillaspy GE. 2003 An Arabidopsis inositol 5-phosphatase gain-of-function alters abscisic acid signaling. Plant Physiol. 32:1011-9.    [Abstract]

Berdy, S. E., Kudla, J., Gruissem, W., and G. E. Gillaspy (2001) Molecular characterization of At5PTase1, an inositol phosphatase capable of terminating inositol trisphosphate signaling.1[w] Plant Physiology 126:801-810.   [Abstract]

Gillaspy, G. E. and Gruissem, W. (2001) Li+ induces hypertrophy and down regulation of myo-inositol monosphosphatase in tomato. J. Plant Growth Regul. 20:78-86.

Gillaspy, G. (2001) A change of heart. Finding the right balance. Plant Physiol 27: 377-8.    [Abstract]

Styer, J., Gruissem, W., and Gillaspy, G. (1999) Spatially regulated expression of tomato inositol monophosphatase genes. Plant Physiol. Supplement.

Goley, M., Oda, K., Gruissem, W., and Gillaspy, G. (1999) Transgenic reduction of inositol monophosphatase disrupts development of tomato. Plant Physiol. Supplement.