The impact of the triploid block on the origin and evolution of polyploid plants

Köhler, Claudia; Scheid, Ortrun Mittelsten; Erilova, Aleksandra

doi:10.1016/j.tig.2009.12.006

Cited by 209 publications

(223 citation statements)

References 86 publications

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“…The few empirical studies available show that the postzygotic barrier, both in terms of rate of hybrid formation and its fitness, is lower among the various polyploid cytotypes than it is between diploids and their polyploid derivatives (Greiner and Oberprieler, 2012;Sonnleitner et al, 2013;Hülber et al, 2015;Sutherland and Galloway, 2017). This corresponds well with the explanation of maternal: paternal genome imbalance in the endosperm as a primary cause of the postzygotic barrier (Köhler et al, 2010;Greiner and Oberprieler, 2012). Because the magnitude of endosperm imbalance in tetraploid-hexaploid hybrids is approximately one third lower than in diploidtetraploid hybrids (Sonnleitner et al, 2013) these higher-ploidy hybrids may be more fit than diploid-tetraploid hybrids.…”

Section: Sampling Of Standing Variation From Local Introgressionsupporting

confidence: 61%

“…Thus, gene flow in the 4x -> 2x direction is less likely as it involves two separate crossing steps (4x -> 3x and 3x -> 2x). Moreover, the triploid hybrid is often either non-viable (triploid block) or unfit (Ramsey and Schemske, 1998;Köhler et al, 2010). Indeed, the few available empirical genetic studies document either much stronger (in autopolyploid systems : Ståhlberg, 2009;Jørgensen et al, 2011;Arnold et al, 2015) or exclusively unidirectional gene flow from the diploid into the polyploid (in allopolyploid systems: Slotte et al, 2008;Chapman and Abbott, 2010;Zohren et al, 2016).…”

Section: Sampling Of Standing Variation From Local Introgressionmentioning

confidence: 99%

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The “Polyploid Hop”: Shifting Challenges and Opportunities Over the Evolutionary Lifespan of Genome Duplications

et al. 2018

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The duplication of an entire genome is no small affair. Whole genome duplication (WGD) is a dramatic mutation with long-lasting effects, yet it occurs repeatedly in all eukaryotic kingdoms. Plants are particularly rich in documented WGDs, with recent and ancient polyploidization events in all major extant lineages. However, challenges immediately following WGD, such as the maintenance of stable chromosome segregation or detrimental ecological interactions with diploid progenitors, commonly do not permit establishment of nascent polyploids. Despite these immediate issues some lineages nevertheless persist and thrive. In fact, ecological modeling commonly supports patterns of adaptive niche differentiation in polyploids, with young polyploids often invading new niches and leaving their diploid progenitors behind. In line with these observations of polyploid evolutionary success, recent work documents instant physiological consequences of WGD associated with increased dehydration stress tolerance in first-generation autotetraploids. Furthermore, population genetic theory predicts both short-and long-term benefits of polyploidy and new empirical data suggests that established polyploids may act as "sponges" accumulating adaptive allelic diversity. In addition to their increased genetic variability, introgression with other tetraploid lineages, diploid progenitors, or even other species, further increases the available pool of genetic variants to polyploids. Despite this, the evolutionary advantages of polyploidy are still questioned, and the debate over the idea of polyploidy as an evolutionary dead-end carries on. Here we broadly synthesize the newest empirical data moving this debate forward. Altogether, evidence suggests that if early barriers are overcome, WGD can offer instantaneous fitness advantages opening the way to a transformed fitness landscape by sampling a higher diversity of alleles, including some already preadapted to their local environment. This occurs in the context of intragenomic, population genomic, and physiological modifications that can, on occasion, offer an evolutionary edge. Yet in the long run, early advantages can turn into long-term hindrances, and without ecological drivers such as novel ecological niche availability or agricultural propagation, a restabilization of the genome via diploidization will begin the cycle anew.

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Section: Sampling Of Standing Variation From Local Introgressionsupporting

confidence: 61%

Section: Sampling Of Standing Variation From Local Introgressionmentioning

confidence: 99%

The “Polyploid Hop”: Shifting Challenges and Opportunities Over the Evolutionary Lifespan of Genome Duplications

et al. 2018

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“…For instance, crosses with triploids revealed that euploid gametes of triploids can be 1x, 2x or 3x (Husband, 2004;Van Huylenbroeck et al, 2005). Although these 2x gametes are not exactly 2n gametes (they are 3x gametes), they result in higher ploidy levels of the progeny and mostly act as a bridge between diploids and tetraploids (Köhler et al, 2010).…”

Section: Sources Of 2n Gametesmentioning

confidence: 99%

Use of 2n Gametes in Plant Breeding

Dewitte¹,

Laere²,

Huylenbroeck³

2012

Plant Breeding

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“…This suggests that polyspermic zygotes in the embryo sac can develop into mature triploid embryos if the balance of male to female genomes in the endosperm is within a permissible range. 52 Polyspermy in angiosperms might be a pathway for the formation of triploid plants, which can contribute significantly to the formation of autopolyploids.…”

Section: Resultsmentioning

confidence: 99%