This project is aimed toward the elucidation of intracellular signalling pathways that involve calcium in the transduction of hormonal and environmental stimuli in higher plants. The project is focused on the necessity and sufficiency of changes in cytosolic calcium activity in aleurone cells from wheat seeds after hormonally- or environmentally-induced germination. The early signal transduction events in the seed culminate in a change in gene expression in the aleurone cells. Cytosolic calcium activity changes will be determined in individual cells fluorometrically, and changes in calcium channel activity that underlie the redistribution of calcium will be assessed by patch clamp studies. Finally, the timing of the changes in gene expression will be compared with the timing of shifts in cytosolic calcium activity. The thrust of the project is to link transient shifts in cytosolic calcium activity with specific changes in channel activity and with changes in transcription and translation. %%% This study is directed toward intracellular signalling pathways in higher plants. In the process of seed germination, much is known about hormonal activation of the aleurone cells in the seed and much is known about the changes in gene expression that follow several hours after hormonal stimulation, but the intermediary steps of hormonal reception and intracellular signal transduction that lead to altered transcription and translation remain elusive. This project will provide significant, new information on the involvement of calcium in the cascade that culminates in altered gene expression in developing seeds of wheat.
