The age of discovery

Research in rice genomics could be the key to eradicating hunger through environmentally sustainable methods, says Latha Rangan

By Latha Rangan
Published: Monday 15 July 2002

The age of discovery

Approximately 80 per cent of all calories consumed in the world come from genomes that are similar to rice. The fact that the rice genome is relatively small, and the availability of modern efficient genetic transformation techniques, have enabled rice scientists to explore this grass in depth. An essential aspect of rice genomics will be 'allele mining', helping the development of more desirable varieties of rice by isolating certain qualities.

The population of rice consumers is increasing at the rate of two per cent per annum. However, the rate of growth of rice production has slowed to a worrying 1.2 per cent. Rice production, therefore, needs to increase by 70 per cent by the year 2020 to meet the expected demand. With very limited scope for expanding the existing rice growing area and diminishing water supply, scientists and policymakers turn their attention to producing more rice in less land.

Over the next 20 years, the rice genome will make a greater difference to global health than the human genome. By unravelling a crop's genetic map, a scientist allows desirable traits to be targeted and crossbred into a 'super-plant'.

The Swiss agro-chemical firm Syngenta, which has partially decoded japonica 's genetic map, claims that this is the foundation for the world's food supply, and that the rice genome map will revolutionise plant-breeding efforts. However, Syngenta's initial hesitation in making their data available through GenBank is indicative of the perils that lie ahead. Steven Briggs, who heads the project, believes their effort has a 'significant commercial advantage', when asked why the company was reluctant to deposit its sequence into public domain.

The consolation is that Syngenta, like Monsanto, has promised to assist in the efforts of the International Rice Genome Sequencing Project (irgsp), as a result of which much of the sequence will be amalgamated with data that the public group will deposit. The irgsp, a consortium of public laboratories, aims to complete the sequencing of the entire rice genome by the end of 2005. The consortium has opted for a more systematic, traditional route, which though more accurate, takes longer research time.

This genome-wide sequence will finally provide a directory for all the genes of rice, whether their function is currently known or unknown. Existing and emerging tools of genomics will be used to determine the function of unknown genes. The gravest concern for the project is the continuous flow of financial assistance till the target is attained. The public rice genome project needs worldwide support more than ever before.

Molecular analysis will help enhance our capacity to undertake precision breeding in rice. Plant improvement research has now entered an exciting period in which genomics and proteomics will play a significant role. This is likely to be the pathway for environmentally sustainable advances in the productivity of rice and towards eradicating hunger.

A study of the plant genome will allow more rational approaches totraditional plant breeding. Further-more, as genome analysis becomeseasier and cheaper, we will be able to tackle many crops, such as cowpeas, sorghum, cassava and millet, that have not received much attention so far, thanks to the prevailing 'candidate gene(s)' approach.

Latha Rangan is an academic visitor at the Norman Borlaug Institute for Plant Science Research, Leicester, UK

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