News in Science

Canola genome paves the way for better crops

Oilseed genome The canola plant is set for an overhaul to boost its oil content, make it more disease-resistant, and help it adapt to climate change, thanks to the sequencing of its genome.

An international team of scientists report the sequencing of the Brassica napus genome today in Science .

Brassica napus — also known as canola or oilseed rape — is an essential food crop, providing canola oil for cooking and biofuel, and seed meal for animal fodder.

Canola was hybridised around 7500 years ago from two other Brassica species: Brassica rapa, which includes plants such as Chinese cabbage, and Brassica oleracea, the species that includes broccoli, cauliflower, and cabbage.

Sequencing of the genome reveals the two sub-genomes have been swapping and rationalising their genetic material since that time, aided by human breeding efforts.

"We could see that by cultivating oil seed types, we got accelerated loss of glucosinolate genes, because glucosinolate tastes bad and isn't good for human consumption and animal consumption," says co-author Professor Jacqueline Batley, Future Fellow at the School of Plant Biology, University of Western Australia.

"You can start to look at it in terms of what's required for it to be effective as a cultivated crop, compared to what would have been require for it if it was just out in the wild," Batley says.

However it's not so much the sequencing of the genome that has scientists excited, as much as what can now be done with that knowledge.

Super crop

Despite its worldwide use as an oil crop, oilseed actually has a relatively low level of genetic diversity, which can make it challenge to select and breed for certain genetic traits. However by sequencing the genome, scientists can identify these key genes and work with them to prove the oilseed plant.

"What it enables now is now we can start to, for example, identify genes for disease resistance and actually deploy them in breeding so we can get an improved crop with an improved yield," says Batley.

Researchers can also look to other wild Brassica species, including those that contributed to the Brassica napus hybrid, for desirable genes that could be bred into the oilseed plant to enhance its diversity.

One key direction for this breeding is improving the oil yield of the crop, for example to change the relatively proportions of different fatty acids such as oleic and linoleic acid, or simply to increase the amount of oil that can be harvested from the crop.

Another focus will be helping this major food crop to adapt to climate change, such as by selecting for different flowering times, drought tolerance, or heat tolerance, says Batley.

"The genome itself isn't the important thing, it's what you can do with it afterwards and that really is just crop improvement, understanding the crop and how it works, that's the important thing," Batley says.