Researchers at the University of Calgary, Canada have developed a gene-based technology to produce canola plants that can withstand late-season frost and still produce high-quality seed.
Late season, non-lethal frost prevented chlorophyll – the green photosynthetic pigment found in plants – from naturally breaking down or “degreening” and producing a high-quality yellow embryo at seed maturity, according to a 9 October press release from the university.
Grade No. 1 canola could not have more than 2% of green seeds, but frost could substantially increase this percentage. When processing green seeds to extract canola oil, the chlorophyll reduced the oil’s storability and quality.
Farmers received a lower price for frost damaged green seed canola, costing them about CAD$150M/year (US$114M).
“Now, we’ve been able to create canola lines that can degreen properly,” said Dr Marcus Samuel, associate professor of integrative cell biology in the university’s Department of Biological Sciences.
The new research built on Samuel’s previous work which detailed the molecular pathways for seed degreening in Arabidopsis, a cousin of canola, the university said.
The group found a “master regulator” protein that controlled chlorophyll breakdown and seed maturity, a transcription factor called Abscisic Acid Insensitive 3 (ABI3).
Through genetic manipulation, the expression of ABI3 could be increased in Arabidopsis plants.
“This up-regulation of ABI3 in seed tissue enhanced the seed degreening system and allowed the seed to break down chlorophyll following instances of frost,” said researcher Logan Skori.
Samuel’s research group was able to reduce the amount of chlorophyll in the genetically modified canola lines by 50% to 60% after the plants were exposed to non-lethal frost (-4°C for six hours), the university said.
Samuel also noted that the seed pods’ structure was stronger, which would reduce the issue of “pod drop”, where the whole pod falls to the ground.
PhD student Neil Hickerson said the canola oil had increased levels of nervonic acid, a fatty acid important for brain health, while the plants had higher levels of oleic acid compared with linoleic acid, improving the canola’s storage and overall cooking properties.
The research group’s next step was to knock out the negative regulator of the ABI3 expression directly in the canola plant. “If you take out the negative regulator, you automatically see an up-regulation of ABI3, so it is the same result,” Samuel said.