Most plants do poorly when flooded. Certain rice varieties, known as deepwater rice, survive periodic flooding and consequent oxygen deficiency by activating internode growth of stems to keep above the water. Here, the authors identify the gibberellin biosynthesis gene, SD1(SEMIDWARF1), whose loss-of-function allele catapulted the rice Green Revolution, as being responsible for submergence-induced internode elongation.
As contemporary climate change triggers radical shifts in weather patterns, cryptic genetic variation found in wild rice gene pools may offer adaptive solutions to help breeders fine-tune modern rice varieties.
A transcriptional gain-of-function allele of the Green Revolution semidwarf gene triggers rapid stem elongation in deepwater rice, enabling it to survive adverse flooding conditions. Thus, the same gene has been co-opted several times to permit rice cultivation in highly contrasting production systems via different molecular responses—decreasing enzymatic activity in one case and enhancing transactivation in the other. The capacity of SD1 to function in such diverse roles in cultivated rice highlights the intrinsic complexity and molecular plasticity of plant adaptation strategies.
The full article by Kuroha et al. can be accessed on the Science website.