Hydrogen peroxide functions as a cell death signal for hybrid lethality in the F1 of Nicotiana gossei x N-tabacum

F, seedlings of Nicotiana gossei Domin x N. tabacum L. show hybrid lethality caused by an expansion of programmed cell death from the base of the hypocotyl. The cell death proceeded at 26 degreesC but not at 37 degreesC. The levels of O-2(-) and H2O2, reactive oxygen intermediates, were higher in the plants grown at 26degreesC than 37degreesC. The cell death was suppressed by the application of catalase or inhibitors of NADPH oxidase, but not by superoxide dismutase (SOD) or mangan-desferrioxamine. This suggests that H2O2 is involved in the cell death process rather than O-2(-). The cell death was promoted in the F, hybrid of N. gossei x transgenic N. tabacum overexpressing the rice CuZn-SOD, whereas it was suppressed in the F, hybrid of N. gossei x transgenic N. tabacum overexpressing the rice cytosolic ascorbate peroxidase. Thus H2O2 causatively links to cell death in the hybrid. (C) 2004 Elsevier Ireland Ltd. All rights reserved.