Abstract
Deepwater rice is cultivated in Southeast Asia where serious flood occurs periodically. To avoid flood condition, deepwater rice elongates its internode along with the rising water. QTL analysis revealed one major QTL for internodal elongation on the long arm of chromosome 12.
By positional cloning, we identified two genes, named Snorkel1 (SK1) and Snorkel2 (SK2) regulated deepwater response. SKs were not expressed in air condition, but the expressions were strongly induced in deepwater. To confirm SK1 and SK2 induce deepwater responses, we conducted gain-of-function analysis. Transgenic plants showed responses to deepwater. Furthermore, we produced the transgenic plants that overproducing SK1 or SK2. Vector control plants did not any response. In contrast, the SKs overproducing plants elongated internodes significantly even in air condition. These results indicate that the SKs are the key genes for internode elongation under water submergence condition in deepwater rice.
