2004 年 54 巻 4 号 p. 347-350
Interspecific hybrids of Nicotiana repanda × N. tabacum die shortly after germination. Seedlings that are hybrids between N. repanda and N. tomentosiformis, which is a progenitor of N. tabacum, express hybrid lethality when they are cultured at 28°C for 90 days after germination, but seedlings that are hybrids between N. repanda and N. sylvestris, another progenitor of N. tabacum, grow normally. We detected several features of programmed cell death (PCD) in hybrid seedlings of N. repanda × N. tomentosiformis expressing hybrid lethality. Nuclear fragmentation was detected in nuclei isolated from dying shoots and roots of hybrid seedlings expressing lethality. In addition, electrophoresis of total DNA extracted from the shoots and roots of hybrid seedlings showed a distinctive DNA ladder pattern, suggesting cleavage of nuclear DNA into oligonucleosomal fragments. These results indicate that hybrid seedlings of N. repanda × N. tomentosiformis undergo PCD in the process of hybrid lethality. However, in hybrid seedlings of N. repanda × N. sylvestris, no features of PCD were detected. These results suggest that PCD might also be expressed in hybrid seedlings of N. repanda × N. tabacum because N. tomentosiformis is a progenitor of N. tabacum.
