In regions that traditionally support cereal crops, penetration of the viticulture industry has been difficult because of widespread use of 2,4-D broadleaf-weed killer on large industrial fields. Typical formulations of the ubiquitous herbicide are highly volatile and are prone to drifting long distances. Unfortunately, grapes display a high sensitivity to even minute exposure to 2,4-D, which causes serious injury, crop losses and even vine death.
This technology is a method for genetically modifying and successfully cultivating a transgenic variety of the Chancellor Grape that can tolerate up to twenty times the rate of 2,4-D used to control broadleaf weeds in corn. The invention could allow for the establishment of wineries in Midwestern and Eastern areas where there is extensive use of 2,4-D.
The Midwest was once a major grape and wine producing region in the United States, but widespread use of 2,4-D herbicide on corn and soybean fields beginning in the 1950s stalled vineyard production and expansion. Over the past decade, Illinois has seen a reemergence of viticulture in the Southern and Central regions of the state. Acreage of vineyards has increased almost 500 percent, since 1997.
To meet increasing demands for resilient, productive grape varieties and to provide support for local vineyards, this technology was developed to alleviate some of the tensions that accompany growing grapes in the vicinity of industrial crops and farms.
Because there is no known 2, 4-D resistance in grape germplasm, 2, 4-D breakdown genes had to be engineered by somatic embryogenesis into select Chancellor Grape DNA to improve grape survival rates in cereal-crop growing regions. By incorporating the modified tfdA gene into the Chancellor's genetic sequence, this invention provides the encoding for an enzyme that degrades 2,4-dichlorophenoxyacetic acid (2,4-D) to dichlorophenol (DCP). The synthetic DNA sequence comprises a natural microbial sequence that encodes the enzyme in which at least a plurality of the codons of the natural microbial sequence have been replaced by codons more preferred by a plant.
This invention also provides methods of selecting plants and plant cells that have been transformed with a DNA construct according to the invention using an auxin herbicide.
- Quality grape production: The Chancellor wine grape is a complex hybrid developed in France by Albert Siebel in the late 1800s and introduced into the United States in the 1940s. Chancellor wine is a dry, heavy bodied grape with a rich plum-cedar aroma and a dense ruby-violet color, which is grown for its earthy taste and is frequently used in wine blends.
- Suited to Midwest cultivation: Chancellor Grape vines are vigorous and high yielding plants with moderate susceptibility to powdery mildew when growing under hot, moist and calm conditions such as exist in the eastern U.S. The warm and moderately drying breezes of the Midwest provide the ideal microclimates for growing Chancellor Grapes.
- Resists 2, 4-D herbicide: This transgenic variety of Chancellor Grape, a French-American hybrid that is popular in the Northeast and Midwest because of its ability to grow in harsh conditions, can now be grown in close proximity to fields that use the broadleaf weed killer.
- Grow multiple crops: Farmers who wish to diversify their crops in order to protect against price fluctuations and to attract tourist interest can plant Chancellor Grape vines without concern of interference from herbicide treatment.
- Manageable, Prolific crop: The Chancellor Grape vine is known for its relatively low maintenance. It requires minimal pruning and produces large grape clusters that are easy to spray and pick.
- Potential to modify other species: With further research, the tfdA gene could potentially be incorporated into other species of grape, offering growers even more latitude in choice of plant and vineyard location.