Transcript levels of the nuclear-encoded respiratory genes in rice decrease by oxygen deprivation: evidence for involvement of calcium in expression of the alternative oxidase la gene

We investigated the effect of oxygen on the expressionse of respiratory genes encoded in the nuclear and mitochondrial genomes of rice (Oryza sativa L.). Hypoxic treatment decreased the transcript levels of nuclear-encoded, but not mitochondrial-encoded respiratory gents. The effects of ruthenium red (an inhibitor of Ca2+ fluxes from organelles) and/or CaCl2 on plants under hypoxic conditions suggested that Ca2+ is a physiological transducer of a low-oxygen signaling pathway for expression of the alternative oxidase 1a gene (AOX1a), but not for expressions of genes involved in the cytochrome respiratory pathway, in rice. (C) 2000 Federation of European Biochemical Societies.