Rice genetic code broken

Researchers claimed Wednesday they managed to identify all rice genes. So now it became possible to change the production of the most popular grain.

The genetic code of rice, the world's most important crop, has been unravelled in detail by an international team in a project that will also transform research on British crops.

The first genetic code of a food crop to be read in detail, the DNA of rice has 400 million genetic letters holding 37,544 genes in all - about 12,000 more genes than humans - and is unveiled today in a scientific journal.

Previous studies have reported a draft sequence, but an international consortium has now taken the genetic sequence to the point where it will be much more useful to scientists and plant breeders looking to improve existing rice varieties and develop new ones, both by traditional methods and by genetic modification.

Consumption trends suggest that 4.6 billion people will be reliant on rice crops by the year 2025, necessitating a 30 per cent increase in world production.

Prof Rod Wing, of the University of Arizona and a member of the consortium, said: "Demand is expected to double in 50 years, so we need to learn all we can about rice."

The crop is closely related to other major cereal grasses - including corn, wheat, barley, rye, sorghum and millet - that collectively supply two third's of humanity's food.

"This has transformed the way we study the UK's main crops - wheat and barley," Prof Michael Bevan of the John Innes Centre was quoted as saying by Telegraph.

Using the rice genome, his colleague Graham Moore has found a DNA feature in wheat called the "pairing locus", which led to the variety that underpinned bread-making in western and middle eastern civilisations. "All bread wheats are maintained by this pairing locus," said Prof Bevan.

Rice (Oryza sativa) has been central to human nutrition and culture for 10,000 years and the study will aid efforts to feed the world's rapidly increasing population, according to members of the International Rice Genome Sequencing Project, which included the John Innes Centre in Norwich.

Rice is the staple food for more than half of the world's population - with three billion people dependent on it worldwide. However, growing it uses large volumes of water and, compared with similar crops, it is inefficient. It is also vulnerable to drought.

While 90 percent of Arabidopsis proteins also occur in rice, only 71 percent of rice's proteins occur in Arabidopsis. That suggests that rice may hold many rice-specific or cereal-specific genes, scientists said.

The IRGSP was launched in 1997. Scientists had aimed to finish the work by year 2008, but completed the task three years ahead of schedule.

The finished rice genome is accelerating discoveries in other areas. Scientists have used the finished sequence to identify genes that control some fundamental processes, such as flowering, Xinhua informs.

Rice's similarity to barley also has helped researchers identify genes responsible for resistance to barley powdery mildew and stem rust, two major crop diseases.

"The map-based sequence has proven useful for the identification of genes underlying agronomic traits. The (discoveries) identified in our study should accelerate improvements in rice production," scientists affirmed in the Nature article.