Abstract 9728024 Crain The biochemical mechanisms by which plants perceive and respond to changes in the environment are poorly understood. This investigator believes that the breakdown of phosphoinositide lipids brings environmental information into the plant cell. Phosphoinositide breakdown produces inositol phosphates and diacylglycerol, which play key roles in regulating cell physiology. Phosphoinositide specific phospholipases C (PLC) are critical in the transduction of hormonal and environmental signals in animal cells. Plant cells also contain PLCs specific for phosphoinositides, and there is evidence that these enzymes are involved in mediating plant cell response to environmental stimuli. Although some of these enzymes have been partially purified and some cloned, little is known about the properties or regulation of these enzymes, or how many PLCs are present in plant cells. The experiments described here will investigate this class of enzymes in order to understand their regulation and role in plant responses to environmental signals. The enzymes will be identified in oat roots and purified, sequenced and cloned, and their regulation examined. The research described here will identify, purify and study the regulation of phospholipase C enzymes in plants, which breakdown lipids known as phosphoinositides, and which are thought to play an important role in the perception of and response to environmental stimuli. ***
