Scientists discover gene that influences seed development, but environment still holds sway over how big they grow
Every canola grower wants pods filled with large seeds. And most canola crushers want more oil in those seeds, so they can sell more canola oil.
A recent discovery in England could satisfy both of those wishes.
Charlotte Miller, a geneticist at the John Innes Centre in Norwich, England, has discovered a gene that influences seed development in canola, which could lead to varieties with larger and oilier seeds.
Miller and her research team found that a gene called UPL3 is “highly active in plants with light seeds, and less so in plants with heavy seeds,” pnas.org reported.
Based on that finding, Miller realized that a suppressed UPL3 gene would promote larger seeds in canola plants.
“I’m hoping a bunch of people will use this,” Miller said to pnas.org. “If this technology was used widely in canola breeding, you could expect to see a large increase in yield.”
To make the discovery, the scientists at John Innes Centre grew about 100 varieties of rapeseed. They then harvested and weighed seeds from each variety. Some of the seeds were heavier than others — a proxy for oil content.
Using those results, they then studied the UPL3 gene in Arabidopsis, a model plant used frequently in plant genetics.
When they looked at Arabidopsis types where UPL3 was not active, the seeds were 10 percent heavier than other seeds.
Miller took her research further because she wanted to know how UPL3 was affecting seed size.
It turned out that a protein associated with UPL3 is responsible for destroying other plant proteins, including one called L3C2.
That protein, L3C2, plays a role in producing bigger and oilier seeds.
Therefore, supressing the UPL3 gene allows L3C2 to do its work, which leads to bigger canola seeds.
“It certainly looks quite intriguing since it adds to current knowledge and there also appears to be some natural variation for expression of the candidate gene,” said Isobel Parkin, an Agriculture Canada scientist in Saskatoon who specializes in canola genomics.
That means breeders could use the natural deviation, in existing types of canola and rapeseed, to produce new canola varieties with bigger seeds.
However, taking a discovery from the lab to the field is rarely easy.
“I believe all of the work was carried out in European winter types, so we would need to study the expression of the gene in Canadian spring types,” Parkin said. “In relation to growing in Canada, how long does it take for the lines to mature?”
Such a genetic change doesn’t guarantee larger and oilier seeds. Growing conditions will continue to have a huge influence on seed size and the amount of oil in the seed.
“Both yield and oil content are notoriously sensitive to environment,” Parkin said. “There would have to be substantially more data gathered to ensure direct correlation between the candidate gene effect and the presumed phenotype (result) in the field.”
