Cell Biology

The primary research goal of the Cell Biology lab is to understand how plants respond to environmental signals. We are particularly interested in the cellular and molecular mechanisms by which plants sense changes in their environment and how this information is translated into a developmental or growth response. Within this framework, we have been investigating a number of topics dealing with root biology. A particular topic of interest that has received funding from the National Aeronautics and Space Administration (NASA) is the cellular basis for the directional growth response of roots to gravity, or gravitropism. To this end, we have been investigating the involvement of the cytoskeleton in plant gravitropism. In plants, the cytoskeleton has been shown to play a role in cellular signaling, growth orientation and polarity establishment, and sensing of environmental stimuli. Since the phenomenon of plant gravitropism involves the coordinated response of several cells and tissues in a series of steps that include gravity sensing, signal transduction, and differential cellular growth, it is likely that the cytoskeleton is at least partially involved in each of the phases of gravitropism (Figure1).

Our major approach to studying the cytoskeleton and the gravitropic phenomenon has been at the level of the light microscope employing both traditional preparative microscopy methods and live cell imaging techniques. The use of fluorescent protein-constructs that decorate the plant cytoskeleton and report ion levels in living cells provides a powerful tool to probe into the cellular basis of plant gravitropism and root development (Figure 2).

Figure 2. Hairy roots of Medicago truncatula expressing GFP (A) and a red fluorescent protein-talin construct that binds to the actin cytoskeleton (B). A primary aim of our group is to develop imaging tools to probe into cell biological phenomenon applicable to Medicago truncatula.

Our involvement in the Center for Medicago genomics has primarily been to provide core-imaging support to the participants of the center in an effort to promote collaborative research and interaction among researchers using Medicago truncatula. These efforts are greatly benefited by state of the art facilities for cellular imaging present at the Foundation that include a confocal microscope, a ratio fluorescence imaging system, fluorescent stereomicroscopes and a variety of microtomes for sectioning of fixed plant material. These microscopy approaches coupled with the large scale genomics initiatives offered by the Center should greatly facilitate our understanding of important plant biological questions as they apply to Medicago truncatula.

See Also:
Elison B. Blancaflor Group: Plant Microscopy and Cell Biology