Apoptotic cell death induces temperature-sensitive lethality in hybrid seedlings and calli derived from the cross of Nicotiana suaveolens × N. tabacum

2015

Plant Biotechnology

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Hybrid lethality is one of the sexual barriers preventing wide hybridization. In the genus Nicotiana, hybrid lethality is observed in some interspecific cross combinations. Interspesific hybridization of Nicotiana stocktonii×N. tabacum has not been carried out from the viewpoint of expression of lethality. N. tabacum has an S subgenome derived from N. sylvestris and a T subgenome derived from N. tomentosiformis. In this study, hybrid seedlings from the cross N. stocktonii×N. tabacum, were obtained by ovule culture. The hybrid seedlings were classified as normal seedlings, tumorous types and vitrified plants, and they did not express lethality. Hybrid seedlings from the cross N. stocktonii×N. sylvestris expressed lethality. Moreover, hybrid seedlings from N. stocktonii×N. tomentosiformis also expressed lethality. This suggests that both the S genome of N. sylvestris and the T genome of N. tomentosiformis have factors causing lethality in hybrids with N. stocktonii. However, hybrid seedlings from N. stocktonii×N. tabacum did not express lethal symptoms in this study. We suggested that the factors responsible for lethality in N. tabacum must have been lost or no longer expressed during the process of speciation, probably due to reorganization and modification of the genomes.

mentioning

confidence: 79%

Characterization of hybrid seedlings from crosses of Nicotiana stocktonii Brandegee×N. tabacum L. and N. stocktonii×progenitors of N. tabacum

Muraida

2015

Plant Biotechnology

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“…Q chromosome may carry a gene or genes that induced lethal hybrid seedlings from a cross between N. tabacum and N. suaveolens. Yamada et al (2000) have recently showed that the cell death of hybrid seedlings between N. suaveolens and N. tabacum was due to apoptosis. A gene or genes on the Q chromosome might be related to the process of apoptotic cell death in this cross.…”

Section: Discussionmentioning

confidence: 99%

“…We have recently reported that hybrid lethality in the genus Nicotiana showed characteristic features of apoptosis (Marubashi et al 1999, Yamada et al 2000. The hybrid seedlings between N. suaveolens and N. tabacum showed DNA fragmentation, chromatin condensation and nuclear fragmentation.…”

Section: Introductionmentioning

confidence: 99%

Q Chromosome Controls the Lethality of Interspecific Hybrids between Nicotiana tabacum and N. suaveolens.

Onosato

2002

Breed. Sci.

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Non-viable hybrid seedlings were produced from a cross between Nicotiana tabacum (2n = 48; SSTT genome) and N. suaveolens (2n = 32). Our objective was to identify a N. tabacum chromosome that carried gene(s) inducing hybrid lethality in this cross. We crossed 10 monosomic lines (2n = 47; Haplo-M to Z, except for Haplo-p and Haplo-V) of N. tabacum to N. suaveolens and produced hybrids by test-tube pollination and ovule culture using synthetic media. We pollinated 178 placentae (13 to 62 per cross), cultured 5215 ovules (136 to 840 per cross), and produced a total of 85 seedlings. Of the 85 seedlings, 81 died before the cotyledonary and leaf-expansion stages of growth, while 4 from a cross to Haplo-Q produced viable hybrids. Three plants grew to maturity and flowered but one plant was infected by fungi and died at the young stage. Chromosome counting, RAPD and LSC analyses revealed that 3 viable plants were true F 1 hybrids. These results suggested that the Q chromosome of the S genome harbored a gene or genes that induced non-viable seedlings from a cross between N. tabacum and N. suaveolens.

“…repanda expressing hybrid lethality. Moreover, Yamada et al (2000) reported that hybrid seedlings and calli derived from the cross N. suaveolensϫN. tabacum showed lethality within 2 weeks after germination at 28°C but not under high temperature conditions (36°C).…”

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confidence: 99%

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

Kobori

Masuda

2005

Plant Biotechnology

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Features of programmed cell death (PCD), including nuclear fragmentation and DNA ladders were detected in hybrid cells of Nicotiana suaveolensϫN. 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. Key words:Heat treatment, hybrid lethality, Nicotiana, programmed cell death. Short Communication Copyright © 2005 The Japanese Society for Plant Cell and Molecular BiologyAbbreviations: BAP, 6-benzylaminopurine; CTAB, cetyltrimethylammonium bromide; HT, heat treatment; PCD, programmed cell death; TLCC, thin layer cell culture.were maintained under the same conditions on a 7 day subculture cycle and used for experiments 3 days after subculturing.To remove old medium from cells maintained in suspension culture, hybrid cells were sieved through a 200 mm nylon mesh and about 0.5 g (fresh weight) of cells was transferred to culture dishes (f90 mm) at a high temperature (36°C). Three ml of fresh medium was added and cells were placed in order to form a single layer of cells. Then about 2 ml of the extra culture medium was removed to expose the cells to air in order to keep the dishes under observation. For HT, the dishes were placed in a water bath at 40, 50, 60 and 80°C for 15 min. Then, the dishes were placed at 28°C for 24 h.Hybrid cells cultured at 36°C were transferred to 28°C, which is the lethal temperature for hybrid seedlings (Manabe et al. 1989), and maintained at 28°C in a thin layer cell culture (TLCC) system (Masuda et al. 2003). Hybrid cells were sieved through a 200 mm nylon mesh to remove the clustered cells and were resuspended in 50 ml fresh medium after centrifugation (2,000 rpm, 10 min). Ten microliters of this cell suspension was dropped on a glass slide and observed by light or fluorescence microscopy. The progression of lethality in hybrid cells was estimated from the percentage of dead cells after 28°C treatment for different intervals over 24 h. Dead cells were scored under a light microscope after staining with 2.5% (w/v) Evans Blue. At least three independent experiments were performed with more than 500 cells counted per condition.For cytometric analysis, nuclei were isolated from hybrid cells cultured with or without HT by chopping them in ice-cold buffer (Michaelson et al. 1991) and filtering the macerated tissue through 70 and 20 mm nylon mesh. The nuclei were collected from the filtrate by centrifugation for 5 min at 2,500 rpm, suspended in the ice-cold buffer supplemented with 5 mg/m...