Fighting hunger with non-GM flood-tolerant rice
The CNN article (below) talks about how the team that bred this flood-tolerant rice, led by University of California-Davis professor Pamela Ronald, were trying to remedy conventional breeding's failure to create a flood-tolerant rice strain that was acceptable to farmers.
It also says that they identified a flood-resistant gene in a low-yielding traditional rice variety, isolated the gene (called Sub1A) and introduced it into normal rice varieties, thus generating rice that could withstand being submerged in water for 17 days.
It also quotes Pamela Ronald as saying, "The varieties that were developed from conventional breeding were rejected by farmers because they didn't yield well or taste good." The precise introduction of the Sub1A gene into acceptable varieties avoided this problem.
This flood-tolerant rice was invoked as a GM success story by former UK Government Chief Scientist, David King in a BBC programmere late last year. But in fact it is not GM. It was created via the non-GM biotech process known as marker assisted selection (MAS) - normal breeding informed by knowledge of the genome.
As Peter Melchett noted in commenting on King's deceptive claims, it's "an example of the kind of innovative non-GM plant breeding that is making a lot of progress" in areas where GM has had little success.
Marker assisted selection is not, as the article below suggests, an alternative to conventional breeding, it is a refinement - a means of speeding up conventional breeding methods through making them more precise, which is why it's referred to as "precision breeding" in the article.
Melchett also notes that the UC Davis team "initially tried to develop the rice using both MAS and GM techniques. While the MAS worked well and quickly, GM failed initially, for unknown reasons. The scientists were moving a rice gene into another type of rice, so this failure simply underlines the inherent uncertainty and lack of precision in GM technology."
Much later on the scientists did apparently get the GM process to work finally, but to do that they had to attach the gene they wanted to transfer - sub1A - to a very powerful promoter. The "promoter" is what determines in what parts of the plant, when, and to what extent, the introduced gene (in this case, sub1A) functions (called "expression").
Peter Melchett explains, "The promoter they used is from an ubiquitin gene and it is turned on at a high level in many tissues of the plant, most of the time.
This contrasts with the normal (native) promoter of the sub1A gene, which is turned on only when needed in the plants and at the correct levels. Therefore, while the sub1A gene, run by the ubi promoter may nominally function, it is much more likely to have negative side effects in the plant because of its incorrect expression (called ectopic expression)."
As Melchett goes on to note, "These effects could be harmful to health or the environment, or just have adverse effects on the agronomic properties of the crop (for example, it could cause the crop to grow poorly under some conditions, as has happened in practice with some other GM crops)." (Who can we trust on GM food?)
In other words, while the likes of David King are promoting this flood-tolerant rice as a GM success story that shows the limitations of conventional breeding, it actually shows non-GM plant breeding using MAS works much better and faster than GM, and is less likely to throw up negative side effects.
This reality is acknowledged by a number of leading biotech scientists who have worked with GM - see 'Non-GM biotechnology is the future':
Fighting hunger with flood-tolerant rice
CNN, January 29, 2009
By Peter Ornstein
DAVIS, California - If every scientist hopes to make at least one important discovery in her career, then University of California-Davis professor Pamela Ronald and her colleagues may have hit the jackpot.
Ronald's team works with rice, a grain most Americans take for granted, but which is a matter of life and death to much of the world. Thanks to their efforts to breed a new, hardier variety of rice, millions of people may not go hungry.
About half the world's population eats rice as a staple. Two-thirds of the diet of subsistence farmers in India and Bangladesh is made up entirely of rice. If rice crops suffer, it can mean starvation for millions.
"People [in the United States] think, well, if I don't have enough rice, I'll go to the store," said Ronald, a professor of plant pathology at UC-Davis. "That's not the situation in these villages. They're mostly subsistence farmers. They don't have cars."
As sea levels rise and world weather patterns worsen, flooding has become a major cause of rice crop loss. Scientists estimate 4 million tons of rice are lost every year because of flooding. That's enough rice to feed 30 million people.
Rice is grown in flooded fields, usually to kill weeds. But rice plants do not like it when they are submerged in water for long periods, Ronald said.
"They don't get enough carbon dioxide, they don't get enough light and their entire metabolic processes are thrown off. The rice plant tries to grow out of the flood, but when it does, it depletes its sugar reserves. It starts to break down its chlorophyll, important for photosynthesis. It grows really quickly, and then when the flood recedes, it just dies. It's out of gas."
Normal rice dies after three days of complete flooding. Researchers know of at least one rice variety that can tolerate flooding for longer periods, but conventional breeding failed to create a strain that was acceptable to farmers.
So Ronald and her colleagues -- David Mackill, senior scientist at the International Rice Research Institute in the Philippines and Julia Bailey-Serres, professor of genetics at the University of California-Riverside -- spent the last decade working to find a rice strain that could survive flooding for longer periods.
Mackill identified a flood-resistant gene 13 years ago in a low-yielding traditional Indian rice variety. He passed along the information to Ronald, who isolated the gene, called Sub1, and introduced it into normal rice varieties, generating rice that could withstand being submerged in water for 17 days.
The team relied on something called precision breeding, the ability to introduce very specific genes into plants without the associated baggage of other genes that might tag along in conventional breeding.
"This can be a problem for farmers," Ronald said. "The varieties that were developed from conventional breeding were rejected by farmers because they didn't yield well or taste good."
Using precision breeding, scientists introduced the Sub1 gene three years ago into test fields in Bangladesh and India. The subsequent rice harvests were a resounding success.
"The results were really terrific," said Ronald. "The farmers found three- to five-fold increases in yield due to flood tolerance. They can plant the normal way. They can harvest the normal way and it tastes the same. Farmers had more food for their families and they also had additional rice they could sell to bring a little bit of money into the household."
"The potential for impact is huge," agreed Mackill in a statement on the IRRI Web site. "In Bangladesh, for example, 20 percent of the rice land is flood prone and the country typically suffers several major floods each year. Submergence-tolerant varieties could make major inroads into Bangladesh's annual rice shortfall."
The researchers anticipate that the flood-tolerant rice plants will be available to farmers in Bangladesh and India within two years. Because the plants are the product of precision breeding, rather than genetic modification, they are not subject to the same regulatory testing that can delay release of genetically modified crops.
The U.S. Department of Agriculture conferred one of its highest research awards last December on Ronald, Mackill and Bailey-Serres for their work on submergence-tolerant rice.
But Ronald has no plans to rest on her laurels.
"I feel a great sense of gratitude that I was able to contribute in this way," she said. "But the farmers have asked us, 'Can you develop varieties that are drought tolerant, salt tolerant? Can you develop varieties that are insect resistant?' There are always more things to work on."