A research team from John Innes Center led by geneticist Charlotte Miller has identified a gene controlling both the oil content and the size of canola (Brassica napus) seeds. The findings of the study could improve selective breeding to help farmers produce more oil.

Canola, developed in Canada, is a variety of the rapeseed or oilseed rape plant, which is among the most popular vegetable oil crops worldwide. Miller and colleagues grew about 100 rapeseed varieties, each of which had been previously sequenced at the transcriptome level—revealing which genes each variety expressed, and at what levels—and showing huge variation in gene activity across varieties. Miller also harvested and weighed seeds from each variety, with some seeds heavier than others, a proxy for their oil content.

Miller's team compared differences in seed weight and found that one gene, UPL3, was highly active in plants with light seeds, suggesting that UPL3's protein might be involved in seed development. The researchers then examined mutants with nonfunctional UPL3 in Arabidopsis model and found that their seeds were 10 percent heavier than wild-type seeds. To find out how UPL3 influenced seed weight, the researchers looked for genes already known to be involved in seed development. They found three genes, all regulated by the same protein, LEC2, a transcription factor that increases their expression, leading to larger and oilier seeds.

For more details, read the PNAS Blog article.