Crop Genetic Engineering Project: Development of Dicamba-Tolerant Crops
A Colaborative Project between Don Weeks and Steven Ragsdale
Goal: The goal of this project
is to develop broadleaf crops (e.g., soybeans, cotton, canola, vegetables)
which are tolerant to treatment with commercially-viable levels of the
herbicide, dicamba.
Approaches: The primary approach to creating
dicamba-tolerant crops will involve the isolation of bacterial genes that
encode enzymes that are capable of inactivating Dicamba in a single enzymatic
step. These genes will be genetically engineered to allow high expression
in model plant systems (tobacco and Arabidopsis) and targeted crop
plants. The resulting transgenic plants will be tested to determine
if acceptable levels of tolerance to dicamba can be obtained.
Dicamba-inactivating Enzyme Systems: A collaboration
between the laboratories of Don Weeks and Steven Ragsdale allow the testing of three
separate enzyme systems for Dicamba inactiviation. These include:
1. A three-component dicamba O-demethylase system from Pseudomonas maltophilia, strain DI-6. This enzyme system will be expressed in transgenic plants as three separate genes and also as a single polycistronic gene under the control of a strong constitutive plant promoter.
2. A dicamba O-demethylase from Clostridium thermoaceticum.
3. A dicamba decarboxylase
from Clostridium thermoaceticum.