Heat treatment temporarily suppresses expression of programmed cell death in hybrid tobacco cells (Nicotiana suaveolens*N. tabacum) expressing hybrid lethality

Features of programmed cell death (PCD), including nuclear fragmentation and DNA ladders were detected in hybrid cells of Nicotiana suaveolens×N. tabacum expressing hybrid lethality at 28°C, but not in cells kept at 36°C. Heat treatment (HT, 50°C for 15 min) before transfer to 28°C from 36°C temporarily suppressed the increase in the percentage of dead cells. In hybrid cells without HT, the percentage of Sub G1 nuclei, corresponding to those with nuclear fragmentation increased at 6 h after transfer to 28°C and DNA ladders were detected at 9 h after transfer to 28°C. On the other hand, in hybrid cells with HT, the percentage of Sub G1 increased and DNA ladders were detected 15 h after transfer to 28°C. These results suggest that HT temporarily suppresses PCD during expression of hybrid lethality.