The Ups and Downs of Genome Size Evolution in Polyploid Species of Nicotiana (Solanaceae)

Leitch, Ilia J.; Hanson, Lynda; Lim, K. Yoong; Kovařı́k, Aleš; Chase, Mark W.; Clarkson, James J.; Leitch, Andrew R.

doi:10.1093/aob/mcm326

Cited by 286 publications

(291 citation statements)

References 54 publications

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“…East (1936) noted: "I have crossed Nicotiana Tabacum [sic] and N. rustica, obtaining plants showing more heterosis than any other crosses I have ever observed." Both tobacco (N. tabacum) and N. rustica are allotetraploids of fairly recent origin (<200,000 years ago) that originated from different pairs of parental species (Leitch et al, 2008). Thus, this cross brings together four different genomes that have diverged from each other.…”

Section: Polyploids Exhibit Progressive Heterosismentioning

confidence: 99%

Heterosis

et al. 2010

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Heterosis refers to the phenomenon that progeny of diverse varieties of a species or crosses between species exhibit greater biomass, speed of development, and fertility than both parents. Various models have been posited to explain heterosis, including dominance, overdominance, and pseudo-overdominance. In this Perspective, we consider that it might be useful to the field to abandon these terms that by their nature constrain data interpretation and instead attempt a progression to a quantitative genetic framework involving interactions in hierarchical networks. While we do not provide a comprehensive model to explain the phenomenology of heterosis, we provide the details of what needs to be explained and a direction of pursuit that we feel should be fruitful.

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Section: Polyploids Exhibit Progressive Heterosismentioning

confidence: 99%

Heterosis

et al. 2010

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“…repanda and N. nudicaulis belong to the same section (Leitch et al 2008). When N. repanda is crossed with the two progenitor species of N. tabacum, N. sylvestris and N. tomentosiformis, hybrid lethality is expressed in seedlings of N. repanda×N.…”

Section: Discussionmentioning

confidence: 99%

Identification of genomic factors responsible for hybrid lethality in hybrids between Nicotiana nudicaulis Watson and N. tabacum L.

Liu¹,

Marubashi²

2013

Plant Biotechnology

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Hybrid lethality was expressed in seedlings from crosses between Nicotiana nudicaulis and N. tabacum at 28°C. To clarify the subgenome responsible for this phenotype, we crossed N. nudicaulis with the two progenitors of N. tabacum (SSTT), N. sylvestris (SS) and N. tomentosiformis (TT). Seedlings of N. nudicaulis×N. tomentosiformis did not show any lethal symptoms, and these hybrid seedlings subsequently grew to maturity. On the other hand, in the cross N. sylvestris×N. nudicaulis, all seedlings cultured at 28°C died immediately after germination, and others cultured at 34°C and 36°C were nonviable or abnormal; only one hybrid plant survived. These findings suggest that the S subgenome in N. tabacum is responsible for the lethality occurring in hybrids between N. nudicaulis and N. tabacum. Furthermore, to determine whether the Q chromosome induces this hybrid lethality, we crossed a monosomic line of N. tabacum lacking the Q chromosome with N. nudicaulis. Subsequently, we determined the presence or absence of the Q-chromosome-specific DNA marker in hybrid seedlings. Hybrid seedlings both possessing and lacking the Q chromosome showed hybrid lethality when seedlings cultured at 34°C were transferred to 28°C. From these results, we concluded that the Q chromosome is not responsible for the hybrid lethality observed in crosses of N. nudicaulis×N. tabacum.

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“…Variation in genome size known as "genome size enigma" has been extensively discussed in many studies and was proved to have no correlation with organism structural complexity [3][4][5][6][7]. Also intraspecific variation in genome size have been documented and correlated with phenotypic variations caused by the percentage of heterochromatin and non-coding repetitive DNA sequences [8].…”

Section: Genome Size Variationmentioning

confidence: 99%