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

Abstract

F₁seedlings 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 26C but not at 37C. Reactive oxygen intermediates, O₂^- and H₂O₂, were generated more abundantly in the plants grown at 26C than 37C. Pharmacological experiments, including application of catalase, inhibitors of NADPH oxidase, superoxide dismutase (SOD) or mangan-desferrioxamine, suggested that H₂O₂ is more directly involved in the cell death process. The F₁ hybrids of N.gossei x transgenic N. tabacm expressing rice CuZn-SOD for scavenging O₂^- or rice cytosolic APX for scavenging H₂O₂, were analyzed. The cell death was promoted in the F1 of cross between N. gossei and the transgenic plants with SOD, but it was suppressed in the F₁ with APX. H₂O₂ is causatively linked to the cell death reaction in the hybrid.