Signaling in roots in response to touch and gravistimulation

We primarily use Arabidopsis for gravitropism and touch sensing experiments because of the interesting mutants available and because this plant is amenable to transformation, however some of our studies use corn, Limnobium, and other plant species. We are interested in not only how the gravity signal is transduced in the individual cells of the cap that perceive gravity but also how that signal is translocated to the responding cells in the elongation zone. In addition, we are investigating how roots respond when encountering mechanical stimulation. For these and the gravitropism studies we use time-lapse video, GFP fluorescence microscopy, imaging of ion concentrations, laser ablation, laser tweezers, microinjection, and digital image analysis. More...

The control of root hair and pollen tube growth

Root hairs are initiated in certain epidermal cells (trichoblasts) in the maturation zone of the root and then extend away from the root surface by tip growth. These projections increase the surface area of the root for enhanced nutrient and water absorbtion. How the trichoblast initiates the bulge of a new root hair and how directional tip growth is maintained at the cellular level is a focus of Gilroy lab research. These studies parallel our analysis of pollen tube growth. Pollen tubes are essential for plant fertility and grown by tip growth in a similar manner to root hairs. More...

Hormonal signaling during germination in monocots

The cereal aleurone cell is well established as a model system for studying hormonal regulation of plant cells. The aleurone of the barley grain is a digestive tissue that secretes hydrolases that mobilize endosperm reserves during germination. The synthesis and secretion of these hydrolases (principally alpha-amylases) is under hormonal regulation. Gibberellin (GA) stimulates alpha-amylase synthesis and secretion, whereas abscisic acid (ABA) reverses this effect. The signal transduction events leading from the receptor to the coordination of the complex events that make up and regulate the secretory activity of these cells are still poorly understood. It is these events that we are interested in studying. More...

Lipid-based signaling networks in Arabidopsis and rice

Lipid-based signaling represents a major theme of how eukaryotic cells regulate their function, yet is relatively poorly understood in plants. Through a combination of molecular biology and biochemistry, we are studying the role of the phospholipases that break down membrane phospholipids into signaling molecules in processed such as the control of germination and tip growth. In addition, we are using bioinformatic tools to find the spectrum of proteins likely regulated by phospholipid products to more completely understand the complexities of this critical regulatory network. More...