Dr. Leonard D. Pysh

Thornhill Professor
Chairperson
Department: Biology
Office: 406 Life Science
Phone: 375-2466

pysh@roanoke.edu

Degrees:

  • A.B. Wabash College, 1988 
  • Ph.D. University of California, San Diego, 1994

Course List

Research & Teaching Interests:

Plant Biology
Cell Biology
Molecular Biology

Statement of Research Interests:

Cells, the fundamental units of life, exist in an amazing array of shapes and sizes. These shapes and sizes, however, are so faithfully reiterated from generation to generation that they can be used to distinguish species within unicellular organisms and cell types within multicellular organisms. This faithful reiteration of cell shape indicates that the process of cell shape determination is carefully regulated at the molecular and cellular levels. Cell shape contributes to the form and function of higher orders of structure, such as organs, and, as a result, is an important aspect of development. Interestingly, very little is known about the genetic and molecular mechanisms by which cell shape is determined.

In my lab, we are using the simple plant Arabidopsis thaliana to address these genetic and molecular mechanisms. Arabidopsis has become a model plant as a result of its small size, its simple morphology, its rapid generation time, and its small genome. Arabidopsis roots are simple, consisting of four concentric rings of cells,
these cells each having a stereotypical size and shape. Mutations that affect the shape of the cells in the root have been identified, and a number of the genes at these loci have been isolated. The simple hydrocarbon ethylene
is also known to have a profound impact upon root cell shape. Mutations that affect ethylene perception and response have also been identified.

Biochemical and genetic studies indicate that the cell shape genes and the ethylene perception/response genes interact to determine the final shape of cells in the root. The focus of my research is to understand the roles of these two classes of genes in cell shape determination, using a combination of genetic, cellular, and molecular techniques.