A genetic discovery by a University of Calgary-led international research team offers a solution to a long-standing "green seed problem" in oilseed rape that costs growers millions in losses.

Led by Marcus Samuel of University of Calgary, alongside partners from the Universities of Toronto and the Bordeaux, France, scientists uncovered a plant gene regulatory network that they say could be enhanced to prevent green seeds from occurring in mature oilseed rape (or canola, the group of cultivars grown in the United States and Canada).

"The annual loss in North America alone is close to $150 million (£90m) from this de-greening issue," said professor Samuel. "I want to see this basic science translated into a viable application. Canola is a huge cash crop and we have a real solution to a major problem."

Canola is the major cash crop in Alberta, which produces about 35 per cent of Canada's canola, generating $5 billion (£3bn) of the entire country's $15bn oilseed crop.

However, every year around the time when canola matures, an unpredictable touch of a light frost can damage crop quality and cause severe losses, "The frost doesn't kill off the plant, but it 'fixes' the green colour in the seeds," Samuel explained. "Non-lethal" frosts, occurring at temperatures of zero to minus a degree or two Celsius, can result in up to 20 per cent green seeds – as opposed to mature brown or black seeds – in mature canola.

This presence of chlorophyll (pigment that imparts green colour to plants) in mature seeds affects the oil quality, produces unpleasant flavours and odours, and reduces the oil's shelf life. Over five years, Samuel's research team investigated the de-greening process in a weed species called Arabidopsis, a "model" research plant, the complete genetic makeup of which is known to scientists, and which is a close genetic relative of canola.

The research team, using a "mutant" strain of Arabidopsis that produces mature green seeds, performed genetic analyses that uncovered a pathway required for seed development and removal of unwanted chlorophyll during seed maturation. They found that a protein that regulates gene expression (how the gene's information is used in synthesizing a functional gene product), called ABI3, is important in removing seed chlorophyll and enabling the seeds to de-green.

The team identified that ABI3 regulates expression of a gene, mapped in 2007, that controls chlorophyll degradation, resulting in yellow versus green seed colour. This colour difference was first identified as a trait in the 1800s by genetics pioneer Gregor Johann Mendel, who used it as a marker to study the inheritance of traits.

The team also showed that a higher expression of ABI3 in Arabidopsis led to seeds that were able to de-green normally to produce mature brown-black seeds, despite harsh cold treatments.

"This overexpression allows these plants to withstand cold much better and for the system to be functional even though it's hit with cold," Samuel said. "Given the similarity of Arabidopsis and canola, it would be easy to isolate the same genes from canola and use transgenic technologies (which introduce new genes into organisms) to create varieties that could withstand freezing conditions yet produce mature brown-black seeds."

"We actually have demonstrated in our laboratory tests that the canola genes work the same way."