Effect of Ethanol on the Expression of Two Fructokinases in Rice Seedlings

Germination of rice (Oryza sativa L.) caryopses in the presence of exogenous ethanol (the end-product of alcoholic fermentation under anoxia) results in a decrease of coleoptile and root growth. The ethanol level measured in rice caryopses incubated in 50 mM exogenous ethanol under aerobic conditions was similar to that in caryopses incubated under anoxia. Application of 50 mM ethanol under aerobic conditions induced the production of OsFK2, a fructokinase isoform having a central role in the response of rice to anoxia. The induction of OsFK2 by ethanol was organ-specific: OsFK2 was produced mainly in the embryo and partially in the coleoptile, but not in root tissues. The results of this research suggest that rice can sense ethanol under anoxia and shows a molecular response to oxygen deprivation.