GRAD PROFILE

PhD student working to create herbicide-resistant wheat lines

By Trevor Pritchard

U of S PhD candidate Curtis Pozniak. Photo by Trevor Pritchard

Although a farmer at heart, Curtis Jerry Pozniak admits his research with the Dept. of Plant Sciences is just as stimulating.

"Plant breeding is an exciting discipline because it encompasses genetics, pathology, crop physiology, and molecular genetics." enthuses Pozniak, a U of S PhD candidate.

"Today we might be doing crossing, tomorrow we might be out in the field. We're constantly changing roles, and that's what makes it exciting."

"Every day is a different day."

Pozniak's PhD project involves the creation and characterization of wheat lines that are resistant to imidazolinone, a common class of herbicides used to control weed growth in pea, canola, and alfalfa. Working with Prof. Pierre Hucl, Pozniak selected six resistant lines for analysis.

They discovered that the resistance to imidazolinone was caused by a single gene in five of the six lines, and that in the sixth resistance was controlled by two genes.

"We had found that in all of the lines resistance was due to an altered form of the enzyme that this particular herbicide family targets," says Pozniak.

Enzymes are biological catalysts which lower the amount of energy required for a biochemical reaction to occur. In this case, Pozniak explains, the specific enzyme targeted by the herbicide is responsible for producing amino acids, the building blocks of proteins. Under normal circumstances, the herbicide would bind to the enzyme, preventing the creation of these amino acids and leading to the eventual death of the plant. In the resistant lines, however, the altered enzyme prevents this process from taking place, giving the wheat lines their resistant quality.

To create the resistance to imidazolinone, Pozniak and Hucl used a chemical process called seed mutagenesis, whereby genetic variation is induced naturally in organisms. A widespread process used by plant breeders for decades, mutagenesis increases the variability of DNA within the organism, thus making it easier for plant breeders to select for specific traits.

Acknowledging the current public unease about the possible health risks associated with genetically modified organisms (GMOs), Pozniak adds that his research does not involve genetic manipulation.

"Genetic transformation involves using recombinant DNA technology to insert foreign gene sequences into plants. The mutagenesis process that we utilized does not involve insertion of genetic material."

However, because of the increasing public concern, his research and other similar projects are now subject to the same regulations as those involving GMOs, a development which Pozniak finds unnecessarily stringent.

"Mutagenesis has been used since the late 1920s to develop genetic variability within breeding populations. It seems odd that a technology as old as mutagenesis is now regulated as it is."

Growing up on the family farm near Rama, Sask., Pozniak became well-acquainted at an early age with the challenges and tribulations that face the modern farmer. He cites his parents' approach to agriculture as essential to his own outlook.

"There's a strong stewardship to the land. Our parents taught us when we were growing up, that it's not about money. For me, it's the freedom."

Both Pozniak and his wife, Maureen, have undergraduate degrees in agriculture from the U of S. Although he has accepted a faculty position with the Dept. of Plant Sciences, Pozniak says he still enjoys returning to his parents' farm and involving himself in the "hands-on" aspects of agriculture.

"My dad is a very 'interactive' farmer - he adopts new technologies easily, and he's very interested in trying new things, growing new varieties."

Over the past summer, the Dept. of Plant Sciences submitted a patent application for the resistant lines of spring wheat, a standard procedure which protects the lines from being used without permission. Pozniak estimates that the imidazolinone resistant strains will be available to farmers like his father within the next three to four years.

Trevor Pritchard writes graduate student profiles for the College of Graduate Studies & Research.