Posted on Thu, Apr. 04, 2002 U.S., Chinese scientists set to reveal rice's genetic code By Lisa M. Krieger Mercury News A small grain that feeds much of the world yields its biggest secret today when American and Chinese researchers publish the long-sought genetic code for rice. In a feat certain to accelerate efforts to create crops with special traits, the researchers describe the blueprint for the inner workings of a plant that is a cornerstone of California agriculture and a staple for more than half the world's population. The complete genome sequencing, the first ever of a crop plant, is also expected to help scientists better understand wheat, corn and barley. Together, these crops represent an estimated two-thirds of all calories consumed by people in developing countries, according to the U.N. Food and Agriculture Organization. ``It is a navigational aid for agriculture, something that is potentially very, very valuable to those 800 million people in the world without enough to eat,'' said Dr. Donald Kennedy, former Stanford University president and now a professor of environmental sciences and editor of the journal Science, where the paper was published. The publication of two different rough drafts of the rice genome comes as growing populations and diminishing land have forced the world's farmers to seek greater efficiency in growing plants. The availability of the full genome sequence can make the search for genes easier and faster and allow scientists to pose new questions. Each team studied a different strain of rice. ``The information can be leveraged for improving not just rice, but other crops as well,'' said Thomas H. Tai, research geneticist at the U.S. Department of Agriculture's Agricultural Research Service in Davis. ``And it'll help not just biotechnology, but traditional plant breeding as well.'' A team lead by Dr. Stephen Goff of the Torrey Mesa Research Institute of San Diego detailed the genome of Oryza sativa japonica. Details on japonica are free to academic and government scientists; for commercial researchers, they are offered for a fee. The other effort, lead by Dr. Jun Yu of Beijing Genomics Institute, described the genome of indica rice. This information is freely available to everyone over the Internet. The research will be immediately put to use identifying the multitude of varieties of rice, through a DNA fingerprinting technique similar to that used in humans. More exciting are future plans to scan the genomes of the thousands of strains of rice from seed banks around the world, only one-quarter of which have been commercialized. Scientists will seek traits that could help unlock the genetic potential of the grain. For centuries, plant breeders have tried to raise crop yields by breeding whole plants. It is far more efficient, they say, to find the best individual genes or groups of genes. These genes may hide not only in modern varieties, but also in wild relatives and in the old heirloom varieties that have been saved in the world's ``gene banks,'' created by farsighted plant breeders and conservationists. One of the first targets will be the gene for cold tolerance, which permits germination of seeds in cool damp soils, say scientists. This would be a breakthrough for California's Central Valley rice farmers, who must use chilly snowmelt from the Sierras to water their seeds. Scientists will also seek a gene that boosts the vigor of tiny seedlings. Strong seedlings are better able to compete for sun and nutrients against quick-growing weeds. If weeds pose less of a threat, herbicide use can be reduced, Tai said. ``This should allow us to breed better and stronger growing rice in the future that has less susceptibility to disease and higher quality grain -- as well as open the door to future biotech rices that may be produced,'' said Tim Johnson of the California Rice Commission. Rice farming is a $500 million-a-year business in the state. Production is centered in the Sacramento Valley, with its warm Mediterranean climate and hard, water-holding soils. The state's rice is of the japonica variety -- a medium-grain rice that is soft, clings together, and is slightly translucent. This makes it well-suited for Asian cuisine, paella, risotto and desserts. But critics cautioned against a rush to alter the characteristics of rice without understanding the long-term impact on the environment. ``The gene does not define the plant. What's important is the ecological dynamics of the plant,'' said Beverly Thorpe of the Washington D.C.-based environmental group Greenpeace. While Greenpeace supports any genetic shifts that happen through conventional breeding practices, it opposes any genetic mixing-and-matching not seen in nature. Researchers mapping the rice genome made a startling observation: The 50,000-gene sequence of the lowly rice plant is larger than humans, who have only 30,000 to 40,000 genes. But the rice genes themselves are relatively small. And they are incapable of multitasking -- a trait of human genes and the explanation for what makes us so complicated.