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Barcoding Insects To Track and Control Them

By Dennis O'Brien

Barcodes may bring to mind the sales tags and scanners found in supermarkets and other stores. But U.S. Department of Agriculture (USDA) scientists are using "DNA barcodes" to monitor insects that damage crops as diverse as wheat, barley and potatoes, and to make pest management decisions.

In DNA barcoding, scientists sequence a designated part of an organism's genome and produce a barcode from it for a systematic comparison with the sequenced DNA of other closely related species. DNA barcodes are being developed on a wide range of plants and animals as part of a global effort to catalogue the diversity of life on Earth.

Matthew Greenstone, an Agricultural Research Service (ARS) entomologist at the agency's Invasive Insect Biocontrol and Behavior Laboratory in Beltsville, Md., is using DNA barcodes in an unconventional way: to identify insect predators best equipped to control the Colorado potato beetle, which is the single most damaging insect pest of potatoes in the Eastern United States.

ARS is USDA's chief intramural scientific research agency, and this research supports the USDA goal of promoting agricultural sustainability.

Numerous studies have analyzed the gut contents of predatory insects to evaluate their ability to control pests in a field. But predators digest prey at different rates, so simple gut analysis is insufficient for accurately comparing the effectiveness of different predators. Greenstone has fine-tuned the approach, using barcodes to come up with a way to factor in how quickly different insects digest prey.

He and his colleagues collected four potato beetle predators, fed them lab-raised potato beetles and determined how long the pest's barcoded DNA could be detected in the predators' guts. The results, published in the journal Entomologia Experimentalis et Applicata, show the importance of taking digestive rates into account when evaluating insect predators as biocontrol agents. They also may provide guidance to growers on the most effective control strategies for combating a voracious pest.


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How a Desire to Lead Brought This Wheat Breeder to Canada

Video: How a Desire to Lead Brought This Wheat Breeder to Canada

Gurcharn Singh Brar is a wheat breeder whose path meandered from the breadbaskets of Punjab, India, to the sprawling fields of the Prairies. In a candid conversation, Brar shared insights into his journey, the challenges faced, and the undying passion that fuels his quest for better crops.

It all began with a childhood rooted in the wheat fields of Punjab, where agriculture isn’t just a livelihood but a way of life. His fascination with wheat and its potential led him to pursue a bachelor’s degree in agricultural sciences at Punjab Agricultural University. It was during this time that he encountered the spectre of rust diseases, particularly stripe rust, which plagued the region’s wheat crops. Determined to combat this menace, he set his sights on a journey that would take him across continents.

Venturing abroad for his graduate studies, he found himself in Saskatchewan at the Crop Development Centre (CDC), working under the mentorship of renowned researchers like Randy Kutcher and Pierre Hucl. Here, he delved deep into the world of wheat genetics, focusing on stripe rust resistance — a quest that would shape his academic pursuits for years to come.

After completing his master’s and Ph.D. in six and a half years, he embarked on a professional journey that would see him traverse academia and research. From brief stints as a research officer to landing his dream faculty position at the University of British Columbia’s Plant Science program, his career trajectory was marked by a strong drive to make a difference in the world of wheat.

Despite the allure of British Columbia’s unique agricultural landscape, he found himself wanting to return to the vast expanses of the Prairies, where wheat reigns supreme. He recently returned to the Prairies and is the new wheat breeder at the University of Alberta in Edmonton.

“The opportunity to lead an established wheat breeding program at the University of Alberta was a dream come true. With the necessary resources and infrastructure in place, I’m excited to drive innovation and develop high-yielding wheat varieties tailored to the unique conditions of northern Canada,” he says.

Brar, one of Seed World Canada‘s 2024 Next-Gen Leaders, has become known for identifying novel sources of resistance to priority diseases and his efforts in developing wheat germplasm with multiple disease-resistant traits.

In addition to his groundbreaking research, Brar is committed to mentoring the next generation of agricultural scientists.

“I believe in nurturing talent and empowering students to pursue their passions,” he says. “Watching my students grow and thrive in their research endeavours is hugely rewarding.”

As he looks ahead, Brar’s vision for the future of wheat breeding is clear: “My number one target is to develop high-yielding wheat varieties adapted to the northern climates of Canada. By focusing on early maturity and strong straw traits, we can maximize yield potential while ensuring resilience to environmental challenges.”

His decision to also join the Prairie Recommending Committee for Wheat, Rye, and Triticale (PGDC) executive as member-at-large came from a desire to play an even more important role in the world of Canadian cereals.