The state of play: genetically modified rice

Written by Adam Barclay and Sophie Clayton

People often argue passionately for or against genetically modified (GM) crops. Rice Today’s aim here is not to take sides in a debate that has often generated more heat than light, but rather to look at the facts—what is actually happening in relation to GM rice with a separate focus on work underway at the International Rice Research Institute (IRRI).

GM crops have been grown commercially since the 1990s. The global coverage of GM crops in 2011 was 160 million hectares in 29 countries reports the International Service for the Acquisition of Agri-biotech Applications. And, they predict that, by 2015, at least 20 million farmers in more than 40 countries will be using the products of biotechnology, including GM crops, on around 200 million hectares.

This article specifically focuses on GM rice—that is, rice that has had a gene or genes from another species or rice variety introduced into its genome using modern biotechnology techniques. This GM rice exhibits the traits conferred by the introduced gene or genes.

As of December 2012, commercialized GM rice had not yet become a reality—which means, farmers aren’t growing it and consumers can’t eat it yet.

12-1-gm-riceThe GM Crop Database of the Center for Environmental Risk Assessment shows that two GM rice varieties (LLRice60 and LLRice62, both with herbicide resistance) were approved in the United States in 2000. Subsequent approval of these and other types of herbicide-resistant GM rice occurred across Canada, Australia, Mexico, and Colombia. However, none of these approvals resulted in commercialization.

In 2009, China granted biosafety approval to GM rice with pest resistance, but no commercial rollout has taken place.

Nevertheless, R&D on GM rice continues to advance in both the public and private sector around the world. GMO Compass notes that Argentina, Australia, Brazil, China, France, India, Indonesia, Italy, Iran, Japan, Mexico, the Philippines, Spain, and the United States have all been involved with GM rice. Bangladesh and South Korea are also engaged in research on GM rice.

Researchers are working on GM rice with higher yield; increased resistance to pests, diseases, and herbicide; better tolerance of drought and salinity; improved nutritional value and health benefits; and higher nitrogen-use efficiency.

Research on GM rice at IRRI

IRRI’s approach to its GM rice R&D is based on a premise that genetic modification has the potential to safely deliver to rice farmers and consumers a number of benefits that cannot be achieved through other breeding methods.

Genetic modification is used as a research tool—to understand gene function—even when there is no intention to develop a GM rice variety, and to develop new GM varieties with added beneficial traits that cannot be found within the rice gene pool.

“Compared with other major crops such as corn (maize) or wheat, rice has an extraordinarily diverse genetic resource base that spreads across at least 24 different species of rice,“ explains Dr. Eero Nissilä, head of IRRI’s Plant Breeding, Genetics, and Biotechnology Division. “This means there is already a very large pool of useful rice genes that breeders can use to develop new varieties of rice with improved traits.

“In fact, less than 5% of our rice breeding focuses on delivering GM rice varieties,” he adds.

Golden Rice

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The best-known and most advanced example of IRRI’s research on GM rice is that of Golden Rice. Unlike other rice, this contains beta carotene—a source of vitamin A (See Golden grains for better nutrition).

By working with a mix of leading agricultural and health organizations, IRRI is helping to further develop and evaluate Golden Rice as a potential new way to help address vitamin-A deficiency. Work on Golden Rice is most advanced in the Philippines, where it is led nationally by Dr. Antonio Alfonso of the Philippine Rice Research Institute.

“We’ve completed some initial field tests in different locations to evaluate and select breeding lines that potentially would meet farmers’ and consumers’ expectations, to see how Golden Rice grows in different environments, and to compare any environmental impacts of Golden Rice with those of other rice varieties,”

Turbocharged C4 rice

IRRI’s most ambitious attempt to genetically modify rice is its C4 rice project. The project, which brings together a mix of international partners, is attempting to make rice much better at photosynthesis, the process of turning sunlight into grain.

Rice uses a C3 photosynthetic pathway, which is much less efficient than plants such as maize that use a C4 pathway. Rice already has all the components required for C4 photosynthesis, but they are distributed “differently” within rice cells. By rearranging the photosynthetic structures within the leaves using genetic modification, it is theoretically possible to switch rice over to C4 photosynthesis— potentially increasing productivity by 50%.

In 2012, the C4 rice project got an injection of financial support valued at US$14 million over 3 years from the Bill & Melinda Gates Foundation, the UK government, and directly from IRRI.

“This is exactly the sort of innovative scientific research that the [UK] Prime Minister was calling for at the Hunger Summit at Downing Street,” said Lynne Featherstone, UK Parliamentary undersecretary of state for international development. “This new funding will enable IRRI to begin producing prototypes of this ‘super rice’ for testing. This could prove a critical breakthrough in feeding an ever-growing number of hungry mouths.”

The research still has a long way to go, but the scientists have already identified crucial genes needed to assemble C4 photosynthesis in rice, and they now aim to produce C4rice prototypes for testing.

Iron-clad rice

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IRRI senior scientist Dr. Inez Slamet-Loedin is leading two other projects on GM rice. Like Golden Rice, the first of these aims to combat the problem of “hidden hunger,” or micronutrient malnutrition, worldwide.

Dr. Slamet-Loedin and her team are developing iron-rich rice. This has the potential to prevent the iron-deficiency anemia that afflicts more than 1 billion people globally, particularly poor women and children (see Iron-clad rice, Rice Today, Vol. 10, No. 3). Iron deficiency and iron-deficiency anemia contribute to increased maternal mortality, stifle children’s cognitive and physical development, and reduce people’s energy.

In its experimental work, IRRI has added two genes to the popular rice variety IR64. One of these is a gene named “ferritin” from soybean, which codes for iron storage. Rice has its own ferritin gene, but adding another increases the plant’s iron storage capacity. Ferritin from soybeans is a major source of iron for vegetarians. Crucially, it provides iron that is highly bioavailable—that is, can be easily absorbed and used by the body. The other gene, which comes from another rice variety, helps transport iron to the grain.

"Adding a ferritin gene will increase iron-storage capacity,” explains Dr. Slamet-Loedin, “but you also need to increase the amount of bioavailable iron reaching the grain—hence, the need for the transporter gene, which allows iron in the leaf, where it is abundant, to be moved to the grain, the part of the rice that is eaten.”

As a bonus, she says, the use of a transporter gene will also increase zinc in the grain. In 2012, IRRI and the Colombia-based International Center for Tropical Agriculture (CIAT) each performed the first confined field trials of iron-rich GM rice outside of Japan, to look at iron content in the grain and to check the performance of rice in different conditions.

Non-GM rice varieties that are relatively high in iron have concentrations of 5–8 parts per million. Dr. Slamet-Loedin’s team targets an iron concentration of 13–14.5 parts per million in rice grain. Given average rice consumption, this could provide 30% of women’s and children’s estimated iron requirements. Early trials at IRRI revealed an iron content of 11–13 ppm, on the cusp of the target.

Further growing, bioavailability, and food and environmental safety tests are still needed as the team works toward iron-clad rice.

Confirming gene function

Dr. Nissilä explains that one of the most important uses of genetic modification at IRRI is in identifying useful genes and confirming the trait they are responsible for. By using genetic modification, researchers can take a rice gene that they suspect may be responsible for a favorable trait, and insert it into another rice plant to see whether the trait of interest is also transferred. If it is, then they know that is the gene they want to target in their conventional breeding programs—which will result in a regular, non-GM rice variety that includes the beneficial gene and associated trait.

For example, IRRI used genetic modification to confirm the major gene responsible for phosphorus uptake—PSTOL1. However, the original rice plant with the PSTOL1 gene was not genetically modified and future varieties bred to include the PSTOL1 gene will not be GM.

Drought-hardy rice

Dr. Slamet-Loedin is also leading IRRI’s efforts to identify useful drought-tolerance genes that could lead to the development of either GM or non-GM drought-tolerant rice varieties (see Overcoming the toughest stress in rice: drought, Rice Today Vol. 8, No. 3). This is more challenging than nutrient-enriched rice because drought itself is complex as well as the way it affects rice crops.

For example, any new variety must be tested in drought conditions of varying severity and length, and at different times during the growing season (drought hitting during the reproductive stage of rice tends to have the worst impact), as well as in different soil types. Furthermore, any new drought-tolerant variety needs to perform well in nondrought conditions too. This project has support from Japan’s Ministry of Agriculture, Forestry, and Fisheries and is a joint effort among the Japan International Research Center for Agricultural Sciences (JIRCAS), which has provided funding; RIKEN, a large public research organization in Japan; and CIAT, which is helping with testing.

Promising GM breeding lines with improved drought tolerance have already been developed. Some of these lines include extra rice genes and some have genes from a tiny plant called Arabidopsis. Over the past few years, the performance of these lines has been tested in drought conditions using screenhouses. In 2011 and 2012, it was time to move the testing outdoors and IRRI and CIAT completed confined field tests of the lines at rainfed lowland sites in the Philippines and upland sites in Colombia, respectively.

Dr. Slamet-Loedin says that to get a rice variety that tolerates drought at different stages during its life cycle as well as different types of drought, “stacking” all the genes for drought tolerance into a single variety could get the best results.

Building expertise on GM rice

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The intention of IRRI’s current research on GM rice is that, one day, new GM lines will be passed on to researchers in national agencies for further development and, if approved, eventually to farmers and consumers.

Alongside the development of this research goes training in biotechnology and genetic modification techniques for rice scientists. This gives them specialized skills to conduct biotechnology research and to build up their expertise and understanding of the area, so that they can respond research opportunities back in their home countries and institutes, and meet their own local needs.

In September 2012, IRRI ran the “Advanced Indica Rice Transformation Course”—the first time ever that the Institute provided training on the genetic modification of rice. Indica rice—the rice most widely produced in South and Southeast Asia—is a broad group of many different types of rice that are usually grown in hot climates.

Nine public- and private-sector participants attended the training from China, Colombia, India, Indonesia, Nepal, the Philippines, and the U.S. They got hands-on experience and learned about biosafety issues and international guidelines for biosafety management in research.

Says one of the trainees, Ms. Ritushree Jain, an Indian national who is doing her PhD at the University of Leeds in the UK, “After this training, I hope that I will be able to make a construct and put some genes into rice plants and especially in indica varieties, which are more susceptible to drought and nematodes. A lot of rice cultivation is affected by drought stress and nematode infestation and these are big problems.

“My hope is that I will be able to find some genes to integrate into Indian rice varieties and develop something new that will help,” she adds.

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Listen!

For the staff at IRRI committed to advancing GM technology, it's not just about solutions but also responsibility. Michael Joyce has this podcast on GM rice for IRRI Radio.

Rice Today (Jan-Mar 2013)

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