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Ferron, C.

Publications and source records attributed to Ferron, C..

5 recordsLinked to original sources

The effects of ploidy and mating system on the evolvability of populations: theoretical and empirical investigations

The amount of genetic diversity is a key parameter to understand the adaptive potential of populations. It has been demonstrated both theoretically and empirically that several factors influence genetic variance. In angiosperms, two of those are the ploidy level and the mating system of the populations. Polyploidy is theoretically known to increase adaptive potential in the long term. Self-fertilization has been theoretically associated with a decrease in genetic variance, even if it lacks empirical support. These factors have been studied independently, but are often shared in plants. However, there is a lack of empirical studies about the joint effects of polyploidy and selfing on genetic variance. In this paper, we conducted theoretical simulations to explore how genetic diversity could be affected by the ploidy level and mating system. We compared the simulation results with empirical estimates of genetic variance from the plant species Erysimum incanum, a selfing species from the Western Mediterranean basin exhibiting three different ploidy levels. We measured a series of phenotypic traits in individuals of each ploidy, obtained by controlled crosses and grown in different climatic conditions. While theoretical approaches showed a positive relationship between ploidy and genetic variance in both the short and long term, empirical results show lower evolvability and transgressive segregation for polyploids, both results being dependent on environmental conditions. Genetic variance in E. incanum polyploids could be related to recent establishment and adaptation to harsh environments, which explains the apparent contradiction with theory, where more settled and established populations are considered.

evolutionary biology↗

Ploidy variation modulates outbreeding response and promotes mating system evolution in a selfing plant lineage.

O_LIOutbreeding response, the phenotypic differences observed between selfed parental lines and their outcrossed offspring, can influence the evolution of selfing strategies. However, such effect remains poorly understood in non-crop species. We investigated the phenotypic outbreeding response variation across ploidy levels in Erysimum incanum, a predominantly selfing plant complex with diploid, tetraploid, and hexaploid populations distributed across the Iberian Peninsula and Morocco. C_LIO_LIWe performed controlled within-population crosses to generate offspring with varying heterozygosity levels across ploidy types. We quantified individual, flower, and reproductive traits, and we estimated fitness components, and assessed trait modularity and phenotypic integration to see how heterozygosity affects trait coordination. C_LIO_LITetraploid showed the strongest and most consistently positive outbreeding responses, particularly in gamete production. Trait-specific outbreeding responses were positively associated with fitness across ploidy levels. Increasing heterozygosity was linked to a reduction in phenotypic integration, suggesting a loosening of trait correlations. C_LIO_LIOur results show that outbreeding response is ploidy-dependent and functionally connected to fitness. This suggests it may act as a selective force promoting outcrossing in highly inbred lineages. We suggest that outbreeding response is a dynamic and evolvable trait, with implications for mating system transitions and diversification in selfing plant populations. C_LI

plant biology↗

Plant-animal below-ground interaction modifies plant phenotype and its above-ground interaction: a review and a new case study

Ecological interactions play a role in promoting and maintaining biodiversity. These interactions form complex networks of interconnected species. Therefore, changes resulting from an interaction in one of the partners can have indirect consequences on subsequent interactions with other species. Since the mutualism-antagonism continuum is a gradient, a shift in the strength and sign of an interaction is possible, highlighting the dynamic nature of interaction networks. In flowering plants, a wide variety of below- and above-ground interactions are established with a single host plant. Changes in the host, derived from such interactions, can modulate the outcome of the remaining connections in both strength and sign, and the overall configuration of the network. Thus, a species can mediate community-wide consequences through its interaction with the host by altering the plant phenotype. We present a case study where a root infection has unexpected consequences on the pollination host, driving phenotypic changes. This study provides new data on the dynamism of species interactions and the importance of obtaining a global view of interaction networks. Disentangling the direct and indirect effects of interactions and their impact on the rest of the interactions in wild communities is essential for a good understanding of the evolutionary and ecological mechanisms that promote and maintain biodiversity.

ecology↗

Can changes in ploidy drive the evolution to allogamy in a selfing species complex?

O_LIThe evolution of mating systems in plants is central for understanding the rise of their diversity on Earth. The transition towards self-fertilization is a well-known example of convergent evolution although the opposite direction is expected to be forbidden according to evolutionary theories. We suggest that the ploidy level could promote changes in the reproductive strategies through its effect on traits related to pollination. C_LIO_LIWe performed controlled crosses on several populations from the polyploid Erysimum incanum species complex, described as predominantly selfing, to evaluate the inbreeding depression. Additionally, we measured mating traits such as floral size, herkogamy, anther exertion, the relative investment in male and female components (P:O ratio) and genetic diversity. C_LIO_LIWe described three ploidy levels in the complex - hexaploids were unknown until now. We found significant differences in the self-pollination success among ploidies and even among populations within the same ploidy. Inbreeding depression was present in higher ploidies, accompanied by bigger flowers with higher anther exposure, increased herkogamy and P:O and genetic diversity. C_LIO_LIThese findings suggest that ploidy could be promoting alternative reproductive strategies to selfing, driving mating system diversification within a selfing species, which has not been previously described in the wild. C_LI

plant biology↗

Ploidy effects on the relationship between floral phenotype, reproductive investment and fitness exhibited by an autogamous species complex

PremiseThe relationships between reproductive investment, phenotype and fitness have been broadly studied in cross-pollinated plants in contrast to selfing species, which are considered less interesting in this area because they are supposed to be a dead-end in any evolutionary pathway. Still, selfing plants are unique systems to study these questions since the position of reproductive structures and traits related to flower size play an important role in female and male pollination success. MethodErysimum incanum s.l. is a selfing species complex exhibiting three levels of ploidy: diploids, tetraploids and hexaploids. This species complex shows traits typically associated with the selfing syndrome. Here, we used 1609 plants belonging to these three ploidies to characterize floral phenotype and spatial configuration of reproductive structures, reproductive investment (pollen and ovules production) and plant fitness. Then, we explored the relationship between all these variables using structural equation modelling across ploidy levels. Key ResultsAn increase in ploidy level leads to bigger flowers with more exerted stamens and a greater amount of pollen and ovules. In addition, hexaploid plants exhibit higher absolute values for herkogamy which is positively correlated with fitness. Phenotypic traits and pollen production are indirectly selected by the relationship among ovules and fitness, maintained across ploidies. ConclusionsChanges in floral phenotypes, reproductive investment and fitness with the ploidy level suggests that genome duplication can be a driver for the reproductive strategy transitions by modifying the investment in pollen and ovules and linking them with plant phenotype and fitness.

evolutionary biology↗