The maize glyceraldehyde-3-phosphate dehydrogenase 4 (GapC4) promoter confers strong and specific anaerobic gene expression in tobacco (Nicotiana tabacum) and potato (Solanum tuberosum). Here we show that the promoter is also anaerobically induced in Arabidopsis thaliana. Histochemical analysis demonstrates that the promoter is anaerobically induced in roots, leaves, stems and flower organs. Surprisingly, the strong anaerobic induction of the promoter is dependent on light and on the substitution of oxygen with carbon dioxide. High carbon dioxide concentration alone does not induce the promoter in the presence of oxygen and light. If anaerobic conditions are generated under complete darkness or if plants are submerged, no induction above background is observed. When transgenic tobacco harbouring a GapC4 promoter-reporter gene construct is analysed for light dependent anaerobic induction, the results are indistinguishable from those with arabidopsis. The implications for using the GapC4 promoter as an anaerobic reporter for monitoring alterations in the anaerobic signal transduction pathway are discussed.