title: Effect of low temperature on ethanolic fermentation in rice seedlings.
abstract: Rice seedlings (Oryza sativa L.) were incubated at 5-30 degrees C for 48 h and the effect of temperature on ethanolic fermentation in the seedlings was investigated in terms of low-temperature adaptation. Activities of alcohol dehydrogenase (ADH, EC 1.1.1.1) and pyruvate decarboxylase (PDC, EC 4.1.1.1) in roots and shoots of the seedlings were low at temperatures of 20-30 degrees C, whereas temperatures of 5, 7.5 and 10 degrees C significantly increased ADH and PDC activities in the roots and shoots. Temperatures of 5-10 degrees C also increased ethanol concentrations in the roots and shoots. The ethanol concentrations in the roots and shoots at 7.5 degrees C were 16- and 12-times greater than those in the roots and shoots at 25 degrees C, respectively. These results indicate that low temperatures (5-10 degrees C) induced ethanolic fermentation in the roots and shoots of the seedlings. Ethanol is known to prevent lipid degradation in plant membrane, and increased membrane-lipid fluidization. In addition, an ADH inhibitor, 4-methylpyrazole, decreased low-temperature tolerance in roots and shoots of rice seedlings and this reduction in the tolerance was recovered by exogenous applied ethanol. Therefore, production of ethanol by ethanolic fermentation may lead to low-temperature adaptation in rice plants by altering the physical properties of membrane lipids.
authors.affiliation: Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki, Kagawa 761-0795, Japan. hisashi@ag.kagawa-u.ac.jp
authors.forename: Hisashi
authors.initials: H
authors.lastname: Kato-Noguchi
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Yasuda
mesh_terms: D000426:Alcohol Dehydrogenase / Q000187:drug effects / Q000378:metabolism; D003080:Cold Temperature; D000431:Ethanol / Q000494:pharmacology*; D005285:Fermentation; D000077604:Fomepizole; D012275:Oryza / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*; D010940:Plant Proteins / Q000187:drug effects / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000201:enzymology; D018520:Plant Shoots / Q000187:drug effects / Q000201:enzymology; D011720:Pyrazoles / Q000494:pharmacology; D011767:Pyruvate Decarboxylase / Q000187:drug effects / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000502:physiology*; D013816:Thermodynamics
chemical_list: D010940:Plant Proteins; D011720:Pyrazoles; D000431:Ethanol; D000077604:Fomepizole; D000426:Alcohol Dehydrogenase; D011767:Pyruvate Decarboxylase