Cytogenetics of Tumor-Bearing Interspecific Triploid Nicotiana glauca-langsdorffii

Ahuja, M. R.; Hagen, George L.

doi:10.1093/oxfordjournals.jhered.a107559

Cited by 5 publications

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“…One of these tumorous interspecific hybrid combinations involving Nicotiana glauca (2n = 24) and N langsdorffii (2n = 18) has been most extensively investigated from the standpoint of genetic nature and physiology of tumour formation (see Ahuja & Hagen, 1967;Bayer, 1982;Smith, 1988). Tumours also occur in hybrids at different ploidy levels invol-*Dedicated to George L. Hagen on his 70th birthday.…”

Section: Introductionmentioning

confidence: 99%

“…However, the tumour expression varies depending on the genomic combination. For example, the tumours are relatively smaller in the triploid GLL compared with the diploid hybrid (GL) or the amphidiploid (GGLL) combinations (Ahuja & Hagen, 1967).…”

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confidence: 99%

“…From these results on the protein profiles and three enzyme systems, it is rather difficult to draw any conclusions regarding the role of specific proteins/enzymes in tumour formation and/or suppression. A detailed cytogenetic analysis by Ahuja & Hagen (1967) of the hybrid derivatives obtained by selfing the partially fertile triploid (GLL) or backcrossing it to N langsdorffii (LL), showed that the tumour expression was enhanced by a threshold of certain N glauca chromosomes on the N langsdorffii background. In other words, the lower the N glauca chromosome number in the hybrid derivatives, the smaller the size of the tumours.…”

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confidence: 99%

“…In a hybrid derivative with a full genome of N langsdorffii along with two glauca chromosomes, very small tumours developed, compared with those in the triploid (GLL). These observations were interpreted to mean that a number of genes on the N glauca chromosomes enhance tumour expression in the N glauca-langsdorffii hybrid combination (Ahuja & Hagen, 1967). Smith (1988) In another experiment, ten plants from the nontumour line (GGLL-NT) were grown in the Further studies on the nature of the nontumour mutant (GGLL-NT) were carried out by Durante et al (1982).…”

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confidence: 99%

“…Progenies of another amphidiploid N debneyi-longiflora, which forms tumours in the greenhouse, do not develop tumours under field conditions. The hybrid N glauca x N longifiora exhibit variable tumour formation in the greenhouse, but tumours fail to develop on plants from the same population grown under field conditions (Ahuja & Hagen, 1967). In a tomato hybrid combination carrying a dominantly inherited gene frosty spot (Frs) from however, tumours failed to develop under field conditions (Doering & Ahuja, 1967).…”

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Genetic nature of a nontumour mutant isolated from tumour-prone amphidiploid Nicotiana glauca-langsdorffii (GGLL): a critical assessment

Ahuja¹

1996

Heredity

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The genetic nature of a nontumour mutant, isolated by Izard (1957) following irradiation of germinating seeds of the tumour-prone amphidiploid Nicotiana glauca-langsdorffii (GGLL-T), is re-examined in the light of previous and current studies on tumour formation in Nicotiana hybrids. As there are lingering questions regarding the dominant nature of the nontumour trait, I shall present experimental evidence and theoretical arguments that suggest that the nontumour condition does not necessarily involve a single dominant gene mutation, but rather mutations affecting tumour expression. In the framework of a genetic model of tumour formation in Nicotiana (Ahuja, 1968), the mutations are probably in those ee loci of N glauca affecting tumour expression, and not in the I element of N langsdorffii, as previously suggested by Smith (1972) and Sekine et a!. (1993). As tumour-prone tissues are highly sensitive to environmental influences, including irradiation, it would be very difficult to obtain a mutation from tumour to a completely nontumour state, as in all likelihood, the irradiation treatments would accelerate tumour formation, or induce variation in the tumour expression. Instead, I propose a different approach for isolating a nontumour mutant, which involves irradiation of haploid cells (pollen) from N langsdorffii (I species) and then pollinating N glauca (ee species) with the irradiated pollen. As the cross N glauca x N langsdorffii normally yields a 100 per cent tumorous progeny, any deviation from this norm, i.e. a nontumour mutant, would be easily detected in the proposed cross. The reciprocal cross involving irradiated pollen from the ee parent N glauca may also be attempted to check the validity of the hypothesis.

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Section: Introductionmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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Genetic nature of a nontumour mutant isolated from tumour-prone amphidiploid Nicotiana glauca-langsdorffii (GGLL): a critical assessment

Ahuja¹

1996

Heredity

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The influence of genomes on autonomous growth of pith cultures of Nicotiana glauca-Langsdorffii hybrids

Cheng

Smith

1973

Planta

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A differential influence of the two parental genomes on cell proliferation and morphogenesis in pith tissue explants can be observed among the various tumorous hybrid combinations between Nicotiana glauca Grah. and N. langsdorffii Weinm.: the F1 hybrid (GL), its amphiploid (GGLL), and two different triploids (GGL and GLL). This influence was evident when the explants were cultured in the presence of exogenous auxin (indole-3-acetic acid, 2.5 μM), supplied either continuously or for a brief period of time. Compared with the F1 and the amphiploid, the higher proportion of N. glauca genomes in GGL cells resulted in greater growth, the higher proportion of N. langsdorffii genomes in GLL cells in lesser growth. In addition, shoots are produced on the GGL callus, while only roots are formed on calli of the other types in the same medium. When, in addition to auxin, a cytokinin [6-(3-methyl-2-butenyl-amino)purine] was added to the culture medium, the differential growth of the different tissue types was less pronounced; at 1.0 μM of the cytokinin, all tissues grew at about the same rate and remained undifferentiated, regardless of their genomic composition.

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An hypothesis and evidence concerning the genetic components controlling tumor formation in Nicotiana

Ahuja

1968

Molec. Gen. Genet.

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Cytogenetics of Tumor-Bearing Interspecific Triploid Nicotiana glauca-langsdorffii

Cited by 5 publications

References 0 publications

Genetic nature of a nontumour mutant isolated from tumour-prone amphidiploid Nicotiana glauca-langsdorffii (GGLL): a critical assessment

Genetic nature of a nontumour mutant isolated from tumour-prone amphidiploid Nicotiana glauca-langsdorffii (GGLL): a critical assessment

The influence of genomes on autonomous growth of pith cultures of Nicotiana glauca-Langsdorffii hybrids

An hypothesis and evidence concerning the genetic components controlling tumor formation in Nicotiana

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