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Weed genes could help feed the world

Field of tall grass

The grass that was studied belongs to a group that includes wheat, barley, forage crops and switchgrass (Source: stock.xchng)

A humble weed native to the Mediterranean and Middle East and viewed by gardeners as an invasive pest could hold the secret to boosting yields of cereals and biofuels, scientists hope.

In a paper published on in the journal Nature, biologists say they had unravelled the genome of Brachypodium distachyon, a small wild grass that offers big promise in plant biotechnology.

Also called purple false brome, this native of the Mediterranean and Middle East is a plant of zero commercial or agricultural importance.

But its tiny, easily manipulated genetic code makes it ideal to serve as a lab testbed for understanding more complex, valuable grasses.

"It has one of the smallest known genomes among grasses, it's easy to work with and is physically small," says one of the investigators, Dr Todd Mockler, an assistant professor of botany at Oregon State University.

"We can grow 50,000 plants in a normal-sized laboratory and do larger experiments.

"The plants are easy to grow, easy to study and have a short lifecycle. And what we learn from Brachypodium will be of critical value in work with other plants of agronomic importance."

First of its kind

Brachypodium is the first member of a sub-family of grasses called Pooideae - a category that includes wheat, barley, forage crops and switchgrass, which is of major interest for biocrop production - to be sequenced.

The grass family has two other sub-families, Ehrhartoideae and Panicoideae, which include corn and rice. These important cereals have already had their genomes unravelled.

Genomic research entails pinpointing genes and understanding how they work in an organism.

In plants, this can unlock knowledge of, for example, genes that confer resistance to drought, offer a bigger head of food grains or boost yields of natural oils that can be used as biofuels.

After identifying these genes, the next step is to insert them - either through traditional cross-breeding or through genetic engineering, an area that is controversial in many countries - into the plant's code to create new strains.

In the new study, the research team found that Brachypodium has 25,532 genes, somewhat fewer than rice (28,236) and sorghum (27,640), from the two other grass subfamilies.

These three grasses share between 77% and 84% of their genes. The relatively narrow diversity shows that the trio of sub-families had a common ancestor between 56 and 72 million years ago.

Tags: wheat, genetics