Flood-Tolerant SNORKEL Rice Offers Farmers Hope

Some rice varieties have the unique ability to overcome floods by stretching their stems with increasing water depth. These deepwater rice varieties can extend their stems to up to four meters above water, facilitating continuous gas exchange with the atmosphere. This is an important adaptive feature, especially for rice crops in Asia where Monsoon season floods regularly wreak havoc. A team of researchers from Japan, led by Yoko Hattori, has now identified the genes responsible for this trait. Their work appears in the current issue of Nature.

The genes, aptly named SNORKEL1 and SNORKEL2, were found to be activated by the gaseous phytohormone ethylene, which accumulates in plants during deepwater conditions because of slow gas diffusion in water as compared to air. Plants that express the SNORKEL genes were also found to accumulate the ethylene-activated hormone gibberellin. Gibberellin's interaction with its protein receptor induces the degradation of DELLA transcription factors, which normally limit cell elongation.

"This discovery will contribute to rice breeding in lowland areas that are frequently flooded during the rainy season," wrote Hattori and colleagues in the paper. The researchers were successful in introducing the SNORKEL genes to high-yielding rice varieties. High-yielding plants expressing the SNORKEL genes offer hope to farmers growing rice in marginal, flood-prone areas.

The paper is available at http://dx.doi.org/10.1038/nature08258 For more information, read http://dx.doi.org/10.1038/460959a