Genetically modified crops are the way forward when it comes to feeding a booming population
Peter Droge, Tan Kim Ping, Qiu Shijia & Uttam Surana
Straits Times 2 Jan 10;
GLOBAL food security will become one of the most difficult problems for mankind in the next 50 years.
With the world population rapidly approaching nine billion people, our planet will have to produce more food in the coming decade than it has collectively done so in the last 10,000 years.
The consequences of food shortage are daunting.
The price of rice, soya bean, corn and wheat climbed to near historic highs in 2008. For the world's poorest, hunger and malnutrition are the direct result of food shortages. Numerous countries, including some on the African continent, the Middle East, India and even China, are confronted with a food security crisis today.
Much of the world's total land area of 150 million sq km is not suitable for agriculture, and nearly all productive land is already exploited.
The pressure to boost food production on this limited land area is compounded by other emerging problems.
Climate change due to rising temperatures and greater extremes of droughts and floods will hit agriculture. India and the United States already suffered sharp harvest reductions because of record temperatures in 2002.
Global warming may also result in further agricultural land loss due to rising sea levels.
Moreover, fuels derived from biological materials are being promoted as a renewable form of energy. Diversion of main food crops such as corn, sugar cane and soya bean for biofuel production looms as a real threat to the world's food security.
The problem of global food supply is, however, not new. It surfaced about half a century ago, and sparked in the 1960s and 1970s an initiative now widely known as the green revolution.
Essentially, the goal was to introduce to underdeveloped and developing countries conventionally produced high-yielding seeds and improved agricultural techniques such as effective methods of irrigation and use of synthetic fertilisers and pesticides.
While partially successful, the innovations of the green revolution did not fully prepare us for the challenges that lie ahead.
In addition to societal changes, a second green revolution is needed that will engage agricultural scientists, researchers and policymakers alike to improve agricultural production.
Recombinant DNA technology is considered by many as a powerful weapon in this new revolution.
There is good evidence that it will lead to breakthroughs in the development of new crops with novel traits.
Genetically modified crops (GMC) usually result from the transfer of foreign genetic material derived from a donor organism to a recipient plant, using the laboratory-engineered and disarmed soil bacterium agrobacterium tumefaciens as a gene-transfer vehicle.
Recently, DNA coated on gold 'micro-bullets' was shot directly into plant cells using 'gene guns', thus representing a promising alternative transfer method.
Introduction of foreign DNA into the plant genome will lead to synthesis of recombinant proteins which, in turn, results in desirable traits due to changes in the plant cell's physiology.
The first GMC - the slow-ripening Flavr Savr tomato - was commercialised in the mid-1990s, and other varieties followed soon.
GMC, mostly modified for agronomic traits such as pest resistance and herbicide tolerance, have been increasingly adopted in many parts of the world.
One of the best-known examples of a GMC modified for enhanced nutritional properties is the golden rice, which contains a higher level of beta-carotene - a vitamin A precursor.
Vitamin A is essential for resistance to disease, protection against visual impairment and blindness, and growth and development in children. Preventable blindness in children and increased risk of severe infections due to vitamin A deficiency is a public health problem in more than half of all countries.
Golden rice is projected to be introduced into the market by 2012, provided that it passes regulatory checks and safety assessments.
Crops that can withstand environmental stress and grow in agriculturally unsuitable regions will play a prominent role in the future.
However, it is now known that salt and drought tolerance are affected by many genes which interact in a complex manner. This explains why conventional breeding techniques have had little success in the generation of these desired traits.
Resistance to salinity, drought and other environmental-stress factors through genetic modification is, therefore, an area of intense research employing recombinant DNA. If successful, the resulting GMC will play a major role in securing global food supply.
The development and use of GMC is not without controversy, however.
Environmental concerns have been raised and are mainly founded on possible transfer of genes from GMC to other plants. For instance, GMC can pollinate neighbouring wild plants and may result in an unintended transfer of foreign genes into the latter.
This could, for example, lead to the spread of pest resistance and impact ecological balances. These are valid concerns and precautionary measures are employed to prevent gene flow. They include the implementation of isolation distances between GMC and non-genetically modified crops, and the use of pollen barriers or traps around fields of GMC.
A second concern is whether consumption of food derived from GMC poses increased health risks such as allergenic reactions or unknown side effects.
So far there has been no substantiated report of health hazards resulting from consumption of foods derived from such crops. Nonetheless, measures to monitor the safety of GM foods are implemented in many countries that subject GM foods to rigorous pre-market assessments.
The Codex Alimentarius Commission, a body under the World Health Organisation and Food and Agricultural Organisation, established in 2003 an internationally recognised guideline prescribing how GM foods are to be assessed for allergenic potential.
The guideline also provides guidance on the assessment of GM foods for potential toxicity, nutritional equivalence with conventional counterparts, and unintended effects that could result from the insertion of foreign genes.
A GM food is allowed into the world market only after the assessments indicate that it is safe for consumption.
In Singapore, the Agri-Food and Veterinary Authority (AVA) has put in place standards that are in line with the Codex guidelines for GM foods. AVA carries out independent assessments of applications from companies intending to market GM foods here. It also receives scientific advice from the national Genetic Modification Advisory Committee.
A second green revolution seems to be in the making, and recombinant DNA technology and the production of GMC - though perhaps not 'magic bullets' - are likely to play a significant role.
With further technological improvements, a range of safer GMC in greater varieties could be generated in order to help sustain global food security.
Associate Professor Droge is from the Nanyang Technological University's School of Biological Sciences. Professor Surana is a principal investigator at the Institute of Molecular and Cell Biology. Ms Tan and Ms Qiu are members of the Secretariat Office of the Genetic Modification Advisory Committee of Singapore.
