Cell death in lethality of species hybrids of Nicotiana is subjected to its own cellular signaling cue and pathway

Abstract

Cell death was compared between two cultured cell lines of interspecific hybrids of Nicotiana. Both lines grow at 37C, but die at 26C. The line TAH5 from N. tabacum x N. africana died faster than GTH4 from N. gossei x N. tabacum. The ROI generated primarily in the cells was H₂O₂ for GTH4 and O₂^- for TAH5. The treatment of DPI and catalase suppressed death of TAH5 and GTH4, respectively. Cell death of GTH4 was promoted by inhibitors of protein phosphatase, and suppressed by inhibitors of protein kinase. However, these treatments did not affect the viability of TAH5. On the other hand, the treatment of inter- and intra-cellular suppressors of Ca²⁺ signaling attenuated the cell death of TAH5, but not GTH4. The results suggest that the execution of cell death in hybrid lethality is under the control of different cellular signaling pathways, depending on the genotype of each F₁ hybrid.