Gene discovery could yield gen-next `super rice`

Washington: Scientists, including an Indian-origin researcher, have identified a set of genes that could be key to the development of the next generation of tough and disease-resistant `super rice`.

"As the Earth`s human population marches towards 9 billion, the need for hardy new varieties of grain crops has never been greater," researchers said. It won`t be enough to yield record harvests under perfect conditions. In an era of climate change, pollution and the global spread of pathogens, these new grains must also be able to handle stress, they said. Researchers at the Michigan Technological University identified a set of genes that could be key to the development of the next generation of super rice. Analysis by biologist Ramakrishna Wusirika and PhD student Rafi Shaik uncovered more than 1,000 genes in rice that appear to play key roles in managing its response to two different kinds of stress: biotic, caused by infectious organisms like bacteria and abiotic, caused by environmental agents, like nutrient deficiency, flood and salinity. Traditionally, scientists have believed that different sets of genes regulated plants` responses to biotic and abiotic stress. However, Wusirika and Shaik discovered that 1,377 of the approximately 3,800 genes involved in rice`s stress response played a role in both types stress. "These are the genes we think are involved in the cross talk between biotic and abiotic stresses," said Wusirika. About 70 per cent of those "master" genes are co-expressive - they turn on under both kinds of stress. Typically, the others turn on for biotic stress and turn off for abiotic stress. Scientists looked at the genes` response to five abiotic stresses - drought, heavy metal contamination, salt, cold and nutrient deprivation - and five biotic stresses - bacteria, fungus, insect predation, weed competition and nematodes. A total of 196 genes showed a wide range of expressions to these stresses. "The top genes are likely candidates for developing a rice variety with broad stress-range tolerance," Wusirika said. The study was published in the journal Plant Physiology.