Overview and Objectives

Fatty acid synthesis and fatty acid elongation are two parts of a critically important pathway in plants. The endproducts are essential components of cell membranes, waxes, and suberin. Two chemical families of herbicide (groups that share similar chemical structures) inhibit fatty acid synthesis, while fatty acid elongation is inhibited by two other families.  This lesson will provide an overview of fatty acid synthesis and elongation, and explain where herbicides inhibit the pathway.  Mechanisms of resistance to these herbicides will be described.

At the completion of the lesson, students will be able to:

1. Describe the fatty acid biosynthetic pathway and its cellular location in plants, including differences between monocots and dicots.
2. Describe the symptoms and identify the inhibited enzymatic steps of susceptible plants treated with herbicides that inhibit fatty acid synthesis.
3. Describe the symptoms and identify the inhibited enzymatic steps of susceptible plants treated with herbicides that inhibit fatty acid elongation.
4. Understand how herbicide use has selected for resistant plants and the mechanisms of resistance.