Evolutionary Consequences, Constraints and Potential of Polyploidy in Plants

Abstract

Polyploidy, the possession of more than 2 complete genomes, is a major force in plant evolution known to affect the genetic and genomic constitution and the phenotype of an organism, which will have consequences for its ecology and geography as well as for lineage diversification and speciation. In this review, we discuss phylogenetic patterns in the incidence of polyploidy including possible underlying causes, the role of polyploidy for diversification, the effects of polyploidy on geographical and ecological patterns, and putative underlying mechanisms as well as chromosome evolution and evolution of repetitive DNA following polyploidization. Spurred by technological advances, a lot has been learned about these aspects both in model and increasingly also in nonmodel species. Despite this enormous progress, long-standing questions about polyploidy still cannot be unambiguously answered, due to frequently idiosyncratic outcomes and insufficient integration of different organizational levels (from genes to ecology), but likely this will change in the near future. See also the sister article focusing on animals by Choleva and Janko in this themed issue.

Structural polymorphisms and distinct genomic composition suggest recurrent origin and ongoing evolution of B chromosomes in the Prospero autumnale complex (Hyacinthaceae)

“…This may be related to the higher amounts of genome restructuring in polyploids than in diploids within this species complex (Jang, 2013; Weiss‐Schneeweiss et al ., 2013). No comparable data yet exist for other plant genera.…”

Toward breeding new land-sea plant hybrid species irrigable with seawater for dry regions

“…Although allopolyploidy may produce desirable environmental characteristic to enhance environmental stress tolerance and increase photosynthetic efficiency, 2,17 it also might produce undesirable effects, relating mainly to genome instability, sterility and dwarfism. Admitting also that a new species irrigable with sea water is successfully created, another issue would arise relating to soil salinization in the seawater-irrigated regions.…”

“…After longtime considered as a hindrance in the route of higher plants evolution, it is admitted now that the polyploidy is a major evolution force that affects plant diversification and speciation, and shape the geographical range of species. 2 Moreover, many crop species are considered as relatively recent allopolyploids, resulting from interspecific hybridization and polyploidy duplications. 3 Due to fusion-compatibility and possible genome combinations, it was recently found that the mitochondrial genome of Amborella trichopoda (a small angiosperm tree) seems to contain genetic material acquired from green algae, mosses and other angiosperms, 4 suggesting that genome fusion may be conceivable between lower and higher distant species.…”

Two reported cytotypes of the emergent orchid model species Erycina pusilla are two different species

“…The most common cytotypes in a species are those with different chromosome numbers, such as polyploids that have resulted from whole-genome duplications. Polyploidy has been shown to be a common event in the evolution of most angiosperms (De Bodt et al 2005;Soltis et al 2008;Jiao et al 2011;Weiss-Schneeweiss et al 2013). Polyploids are assumed to have aided survival for land species during and/or after the Cretaceous-Tertiary mass extinction (Fawcett et al 2009).…”