Variation in competitive ability with mating system, ploidy and range expansion in fourCapsellaspecies

Abstract

This preprint has been reviewed and recommended by Peer Community In Evolutionary Biology (https://dx.doi.org/10.24072/pci.evolbiol.100054)Self-fertilization is often associated with ecological traits corresponding to the ruderal strategy in Grime’s Competitive-Stress-tolerant-Ruderal (CSR) classification of ecological strategies. Consequently, selfers are expected to be less competitive than outcrossers, either because of a colonization/competition trade-off or because of the deleterious genetic effects of selfing. Range expansion could reduce further competitive ability while polyploidy could mitigate the effects of selfing. Although suggested by meta-analyses, these predictions have not been directly tested yet. We compared the competitive ability of four Capsella species differing by their mating system and ploidy level. For vegetative traits we found no difference in competitive ability neither among species nor among populations. For flower production, we found that the two diploid selfing species (C. rubella and C. orientalis) were more sensitive to competition than the diploid outcrosser (C. grandiflora), and that the tetraploid selfer (C. bursa-pastoris) was intermediate. Within C. bursa-pastoris, we also found that sensitivity to competition increased in parallel to range expansion. These results highlight the possible roles of ecological context and ploidy in the evolutionary trajectories of selfing species.

Analysis of diversity-dependent species evolution using concepts in population genetics

“…much lower than the species carrying capacity) but diversification would then decrease and eventually be negative through time, as the number of species would increase. This is in agreement with recent empirical observations in the plant genus Capsella that selfing species are more sensitive to competition than outcrossing ones (Petrone Mendoza et al 2018;Yang et al 2018), and a plausible explanation for the hypothesis that selfing and asexual lineages "senesce" in diversification rates (Ho and Agrawal 2017).…”

Towards the new normal: Transcriptomic convergence and genomic legacy of the two subgenomes of an allopolyploid weed (Capsella bursa-pastoris)

“…Hence, being a selfer like its C. orientalis parent, there was a shift in flower tissues of the expression pattern of the C. grandiflora subgenome towards that of C. orientalis . Similarly, it seems also possible that the dominance of the C. grandiflora inherited subgenome in roots and leaves contributed to the high competitive ability of C. bursa-pastoris , which was similar to that of C. grandiflora but much higher than that of C. orientalis and C. rubella , its two self-fertilizing congeners [63, 64]. It therefore seems that the present study, together with those more focused on fitness of C. bursa-pastoris [63, 64] contributed to better understanding of the causes of the correlation pointed out almost 100 years ago by Shull.…”

Recurrent allopolyploidization events diversify eco-physiological traits in marsh orchids

“…The pace of divergence of allopolyploids from the initial, neopolyploid genomic background will depend heavily on population parameters such as gene flow, generation time and mating systems (Yang et al 2018), or phenological parameters such as the number of flowers per individual and the complexity of pollinator interactions. Given their widespread distribution, possibilities for long-range dispersal and the success of both polyploids, we assume genetic drift isolating these species is likely to have been a minor force for these established allopolyploids in the recent past and the present.…”