Ecological studies of polyploidy in the 100 years following its discovery

Abstract

Polyploidy is a mutation with profound phenotypic consequences and thus hypothesized to have transformative effects in plant ecology. This is most often considered in the context of geographical and environmental distributions—as achieved from divergence of physiological and life-history traits—but may also include species interactions and biological invasion. This paper presents a historical overview of hypotheses and empirical data regarding the ecology of polyploids. Early researchers of polyploidy (1910s–1930s) were geneticists by training but nonetheless savvy to its phenotypic effects, and speculated on the importance of genome duplication to adaptation and crop improvement. Cytogenetic studies in the 1930s–1950s indicated that polyploids are larger (sturdier foliage, thicker stems and taller stature) than diploids while cytogeographic surveys suggested that polyploids and diploids have allopatric or parapatric distributions. Although autopolyploidy was initially regarded as common, influential writings by North American botanists in the 1940s and 1950s argued for the principle role of allopolyploidy; according to this view, genome duplication was significant for providing a broader canvas for hybridization rather than for its phenotypic effects per se . The emphasis on allopolyploidy had a chilling effect on nascent ecological work, in part due to taxonomic challenges posed by interspecific hybridization. Nonetheless, biosystematic efforts over the next few decades (1950s–1970s) laid the foundation for ecological research by documenting cytotype distributions and identifying phenotypic correlates of polyploidy. Rigorous investigation of polyploid ecology was achieved in the 1980s and 1990s by population biologists who leveraged flow cytometry for comparative work in autopolyploid complexes. These efforts revealed multi-faceted ecological and phenotypic differences, some of which may be direct consequences of genome duplication. Several classical hypotheses about the ecology of polyploids remain untested, however, and allopolyploidy—regarded by most botanists as the primary mode of genome duplication—is largely unstudied in an ecological context.

Can enemy release explain the invasion success of the diploid Leucanthemum vulgare in North America?

“…The two root-feeding weevils D. stolidum and C. trisulcatus were both more often found in L. vulgare than in L. ircutianum populations while the opposite pattern was found for the rootgalling tephritid fly O. nebulosa. Yet, in contrast to a generally larger plant size of polyploids (Ramsey and Ramsey 2014), the diploid L. vulgare produced more shoots and flower heads than the tetraploid L. ircutianum and our results suggest that the higher number of shoots of L. vulgare contributed to the higher attack rates of L. vulgare by D. stolidum and C. trisulcatus. Several field studies found differences in herbivore attack between closely related taxa differing in ploidy level (Thompson et al 1997;Nuismer and Thompson 2001;Münzbergová 2006;Arvanitis et al 2008;Halverson et al 2008;Arvanitis et al 2010;Richardson and Hanks 2011;Münzbergová et al 2015).…”

Impacts of Nitrogen and Phosphorus: From Genomes to Natural Ecosystems and Agriculture

“…These differences in genome size reflect underlying genomic processes such as (retro)transposon amplification and deletion and whole-genome duplication (polyploidy). All of these processes can influence molecular evolution, gene expression, and organismal phenotype (Neiman et al, 2009(Neiman et al, , 2013aGerstein, 2013;Mayfield-Jones et al, 2013;Ramsey and Ramsey, 2014;Dodsworth et al, 2015;Selmecki et al, 2015;Soltis and Soltis, 2016). Polyploidy in particular has been implicated in the remarkably successful radiations of angiosperms (Soltis et al, 2009;Jiao et al, 2011;Albert et al, 2013;Tank et al, 2015;Van de Peer et al, 2017) and teleost fish (Van de Peer et al, 2009;Braasch and Postlethwait, 2012).…”

The legacy of diploid progenitors in allopolyploid gene expression patterns

“…Gottlieb ([2], p. 91) A common phenomenon in plant evolution is the hybridization of two diploid species, accompanied by whole-genome duplication, to produce an allotetraploid species with two homoeologous sub-genomes (see contributions by Soltis et al [3], Ramsey & Ramsey [4], Vanneste et al [5], Jiao & Paterson [6]). New allotetraploids contain duplicate copies of every gene that was present in both their parents.…”