Breakdown of self-incompatibility due to genetic interaction between a specific S-allele and an unlinked modifier.

Breakdown of self-incompatibility has frequently been attributed to loss-of-function mutations of alleles at the locus responsible for recognition of self-pollen (i.e. the S-locus).

Differences in mating system and predicted parental conflict affect post-pollination reproductive isolation in a flowering plant.

Mating system shifts from outcrossing to selfing are frequent in plant evolution. Relative to outcrossing, selfing is associated with reduced parental conflict over seed provisioning, which may result in postzygotic, asymmetric, reproductive isolation in crosses between populations of different mating systems. To test the hypothesis that post-pollination reproductive isolation between populations increases with increasing differences in mating system and predicted parental conflict, we performed a crossing experiment involving all combinations of three self-compatible populations (with low outcrossing rates), and three self-incompatible populations (with high outcrossing rates) of the arctic-alpine herb Arabis alpina, assessing fitness-related seed and plant traits of the progeny.

Outcrossing rates in an experimentally admixed population of self-compatible and self-incompatible Arabidopsis lyrata.

The transition to self-compatibility from self-incompatibility is often associated with high rates of self-fertilization, which can restrict gene flow among populations and cause reproductive isolation of self-compatible (SC) lineages. Secondary contact between SC and self-incompatible (SI) lineages might re-establish gene flow if SC lineages remain capable of outcrossing. By contrast, intrinsic features of SC plants that reinforce high rates of self-fertilization could maintain evolutionary divergence between lineages.

No evidence for incipient speciation by selfing in North American Arabidopsis lyrata.

Self-fertilization inherently restricts gene flow by reducing the fraction of offspring that can be produced by inter-population matings. Therefore, mating system transitions from outcrossing to selfing could result in reproductive isolation between selfing and outcrossing lineages and provide a starting point for speciation. In newly diverged lineages, for example after a transition to selfing, further reproductive isolation can be caused by a variety of prezygotic and post-zygotic mechanisms that operate before, during and after pollination.

Declines in occurrence of plants characteristic for a nutrient-poor meadow habitat are partly explained by their responses to nutrient addition and competition.

Species losses and local extinctions are alarmingly common, frequently as a consequence of habitat destruction. Nevertheless, many intact habitats also face species losses, most likely due to environmental changes. However, the exact drivers, and why they affect some species more than others in apparently intact habitats, are still poorly understood.

Limited phenological and pollinator-mediated isolation among selfing and outcrossing populations.

Transitions from outcrossing to selfing have been a frequent evolutionary shift in plants and clearly play a role in species divergence. However, many questions remain about the initial mechanistic basis of reproductive isolation during the evolution of selfing. For instance, how important are pre-zygotic pre-pollination mechanisms (e.

Manipulation of cytosine methylation does not remove latitudinal clines in two invasive goldenrod species in Central Europe.

Invasive species frequently differentiate phenotypically in novel environments within a few generations, often even with limited genetic variation. For the invasive plants Solidago canadensis and S. gigantea, we tested whether such differentiation might have occurred through heritable epigenetic changes in cytosine methylation.

Differential Contribution of P5CS Isoforms to Stress Tolerance in Arabidopsis.

Proline accumulation is a widespread response of plants to salt stress as well as drought and cold stress. In most plant species, two isoforms of pyrroline-5-carboxylate synthetase (P5CS) catalyze the first step in proline biosynthesis from glutamate. In Arabidopsis, these isoforms differ in their spatial and temporal expression patterns, suggesting sub-functionalization.

A shift towards the annual habit in selfing .

An annual life history is often associated with the ability to self-fertilize. However, it is unknown whether the evolution of selfing commonly precedes the evolution of annuality, or . Using a 2-year common garden experiment, we asked if the evolution of selfing in the normally perennial was accompanied by a shift towards the annual habit.

Allelopathic effects of native and invasive Brassica nigra do not support the novel-weapons hypothesis.

Premise: The novel-weapons hypothesis predicts that some plants are successful invaders because they release allelopathic compounds that are highly suppressive to naïve competitors in invaded ranges but are relatively ineffective against competitors in the native range. For its part, the evolution of enhanced weaponry hypothesis predicts that invasive populations may evolve increased expression of the allelopathic compounds. However, these predictions have rarely been tested empirically.

Sibling competition does not magnify inbreeding depression in North American Arabidopsis lyrata.

About half of all angiosperms have some form of molecular self-incompatibility to promote outcrossing. If self-incompatibility breaks down, inbreeding depression (δ) is the main barrier to the evolution of self-fertilisation (selfing). If inbreeding depression is lower than 50% (δ < 0.

No evidence for local adaptation and an epigenetic underpinning in native and non-native ruderal plant species in Germany.

Many invasive species have rapidly adapted to different environments in their new ranges. This is surprising, as colonization is usually associated with reduced genetic variation. Heritable phenotypic variation with an epigenetic basis may explain this paradox.

STRUCTURE is more robust than other clustering methods in simulated mixed-ploidy populations.

Analysis of population genetic structure has become a standard approach in population genetics. In polyploid complexes, clustering analyses can elucidate the origin of polyploid populations and patterns of admixture between different cytotypes. However, combining diploid and polyploid data can theoretically lead to biased inference with (artefactual) clustering by ploidy.

DEG10 contributes to mitochondrial proteostasis, root growth, and seed yield in Arabidopsis.

Maintaining mitochondrial proteome integrity is especially important under stress conditions to ensure a continued ATP supply for protection and adaptation responses in plants. Deg/HtrA proteases are important factors in the cellular protein quality control system, but little is known about their function in mitochondria. Here we analyzed the expression pattern and physiological function of Arabidopsis thaliana DEG10, which has homologs in all photosynthetic eukaryotes.

Preferential Homologous Chromosome Pairing in a Tetraploid Intergeneric Somatic Hybrid ( + ) Revealed by Molecular Marker Inheritance.

The creation of intergeneric somatic hybrids between and is an efficient approach for citrus rootstock breeding, offering the possibility of combining beneficial traits from both genera into novel rootstock lineages. These somatic hybrids are also used as parents for further tetraploid sexual breeding. In order to optimize these latter breeding schemes, it is essential to develop knowledge on the mode of inheritance in the intergeneric tetraploid hybrids.

Small reductions in corolla size and pollen: ovule ratio, but no changes in flower shape in selfing populations of the North American Arabidopsis lyrata.

The shift from outcrossing to selfing is often accompanied by striking changes in floral morphology towards a "selfing syndrome", which is characterized by flowers with reduction in size, pollen: ovule (P/O) ratio, and herkogamy. This study aims to test whether such changes have occurred in the North American Arabidopsis lyrata, which is of particular interest because of the relatively recent transitions to selfing in this system. Flower size, flower shape, herkogamy levels, P/O ratio, and floral integration of six self-incompatible (outcrossing) and six self-compatible (selfing) populations of A.

What causes mating system shifts in plants? Arabidopsis lyrata as a case study.

The genetic breakdown of self-incompatibility (SI) and subsequent mating system shifts to inbreeding has intrigued evolutionary geneticists for decades. Most of our knowledge is derived from interspecific comparisons between inbreeding species and their outcrossing relatives, where inferences may be confounded by secondary mutations that arose after the initial loss of SI. Here, we study an intraspecific breakdown of SI and its consequences in North American Arabidopsis lyrata to test whether: (1) particular S-locus haplotypes are associated with the loss of SI and/or the shift to inbreeding; (2) a population bottleneck may have played a role in driving the transition to inbreeding; and (3) the mutation(s) underlying the loss of SI are likely to have occurred at the S-locus.

The Interaction between Root Herbivory and Competitive Ability of Native and Invasive-Range Populations of Brassica nigra.

The evolution of increased competitive ability (EICA) hypothesis predicts that escape from intense herbivore damage may enable invasive plants to evolve higher competitive ability in the invasive range. Below-ground root herbivory can have a strong impact on plant performance, and invasive plants often compete with multiple species simultaneously, but experimental approaches in which EICA predictions are tested with root herbivores and in a community setting are rare. Here, we used Brassica nigra plants from eight invasive- and seven native-range populations to test whether the invasive-range plants have evolved increased competitive ability when competing with Achillea millefolium and with a community (both with and without A.

Admixture between native and invasive populations may increase invasiveness of Mimulus guttatus.

Self-fertilization and admixture of genotypes from different populations can have major fitness consequences in native species. However, few studies have addressed their potential roles in invasive species. Here, we used plants of Mimulus guttatus from seven native North American, three invasive Scottish and four invasive New Zealand populations to address this.

Evolution of the Selfing Syndrome in Arabis alpina (Brassicaceae).

Introduction: The transition from cross-fertilisation (outcrossing) to self-fertilisation (selfing) frequently coincides with changes towards a floral morphology that optimises self-pollination, the selfing syndrome. Population genetic studies have reported the existence of both outcrossing and selfing populations in Arabis alpina (Brassicaceae), which is an emerging model species for studying the molecular basis of perenniality and local adaptation. It is unknown whether its selfing populations have evolved a selfing syndrome.

Inbreeding depression in self-incompatible North-American Arabidopsis lyrata: disentangling genomic and S-locus-specific genetic load.

Newly formed selfing lineages may express recessive genetic load and suffer inbreeding depression. This can have a genome-wide genetic basis, or be due to loci linked to genes under balancing selection. Understanding the genetic architecture of inbreeding depression is important in the context of the maintenance of self-incompatibility and understanding the evolutionary dynamics of S-alleles.

Disentangling the effects of breakdown of self-incompatibility and transition to selfing in North American Arabidopsis lyrata.

A breakdown of self-incompatibility (SI) followed by a shift to selfing is commonly observed in the evolution of flowering plants. Both are expected to reduce the levels of heterozygosity and genetic diversity. However, breakdown of SI should most strongly affect the region of the SI locus (S-locus) because of the relaxation of balancing selection that operates on a functional S-locus, and a potential selective sweep.