Meiotic chromosome segregation is critical for fertility across eukaryotes, and core meiotic processes are well conserved even between kingdoms. Nevertheless, recent work in animals has shown that at least some meiosis genes are highly diverse or strongly differentiated among populations. What drives this remains largely unknown. We previously showed that autotetraploid Arabidopsis arenosa evolved stable meiosis, likely through reduced crossover rates, and that associated with this there is strong evidence for selection in a subset of meiosis genes known to affect axis formation, synapsis, and crossover frequency. Here, we use genome-wide data to study the molecular evolution of 70 meiosis genes in a much wider sample of A. arenosa. We sample the polyploid lineage, a diploid lineage from the Carpathian Mountains, and a more distantly related diploid lineage from the adjacent, but biogeographically distinct Pannonian Basin. We find that not only did selection act on meiosis genes in the polyploid lineage but also independently on a smaller subset of meiosis genes in Pannonian diploids. Functionally related genes are targeted by selection in these distinct contexts, and in two cases, independent sweeps occurred in the same loci. The tetraploid lineage has sustained selection on more genes, has more amino acid changes in each, and these more often affect conserved or potentially functional sites. We hypothesize that Pannonian diploid and tetraploid A. arenosa experienced selection on structural proteins that mediate sister chromatid cohesion, the formation of meiotic chromosome axes, and synapsis, likely for different underlying reasons.

Environmentally induced epigenetic variation has been recently recognized as a possible mechanism allowing plants to rapidly adapt to novel conditions. Despite increasing evidence on the topic, little is known on how epigenetic variation affects responses of natural populations to changing climate. We studied the effects of experimental demethylation (DNA methylation is an important mediator of heritable control of gene expression) on performance of a clonal grass, Festuca rubra, coming from localities with contrasting temperature and moisture regimes. We compared performance of demethylated and control plants from different populations under two contrasting climatic scenarios and explored whether the response to demethylation depended on genetic relatedness of the plants. Demethylation significantly affected plant performance. Its effects interacted with population of origin and partly with conditions of cultivation. The effects of demethylation also varied between distinct genotypes with more closely related genotypes showing more similar response to demethylation. For belowground biomass, demethylated plants showed signs of adaptation to drought that were not apparent in plants that were naturally methylated. The results suggest that DNA methylation may modify the response of this species to moisture. DNA methylation may thus affect the ability of clonal plants to adapt to novel climatic conditions. Whether this variation in DNA methylation may also occur under natural conditions, however, remains to be explored. Despite the significant interactions between population of origin and demethylation, our data do not provide clear evidence that DNA methylation enabled adaptation to different environments. In fact, we obtained stronger evidence of local adaptation in demethylated than in naturally‐methylated plants. As changes in DNA methylation may be quite dynamic, it is thus possible that epigenetic variation can mask plant adaptations to conditions of their origin due to pre‐cultivation of the plants under standardized conditions. This possibility should be considered in future experiments exploring plant adaptations.

Plant‐soil feedback (PSF) represents an important process affecting natural plant communities. While many previous studies demonstrated the variation in the intensity of PSF between species, the mechanisms driving these differences are still largely unexplored. The aim of the study was to explore the importance of species traits and species phylogenetic relationships on the intensity of plant‐soil feedback. To do this we used a classical design to test plant soil feedback, i.e., a two‐phase experiment consisting of conditioning and cultivation phase. In the conditioning phase, we used 30 different species from the Carduoidea subfamily of Asteraceae and conditioned soil by each of these species separately. In the cultivation phase, we observed growth of four of these species in all the soils. We predict that the intensity of PSF will be more intense between plants which are more closely related than between unrelated species. As an alternative, we explore the possibility that the intensity of PFS will be a function of plant traits related to nutrient acquisition by the plant. The intensity of feedback was significantly dependent on phylogeny in several cases indicating that more closely related species show more similar feedback effects. The feedback response was also affected by the chemical composition of the cultivated soil. In addition, the intensity of feedback was affected by height of the cultivating species and its ability to accumulate nitrogen and phosphorus in their leaves. While in most of these cases there is an indication that plants grow better in soils cultivated by smaller species accumulating less nutrients, in some cases the pattern in opposite. The direction and intensity of plant‐soil feedback also strongly differed between life stages with seedling number commonly showing a response which was opposite to the response of the adults. Synthesis: The results supported our expectation that plant‐soil feedback may be affected by species phylogenetic relationships. In addition, we have shown that also plant traits and the effect of the conditioning plant on soil chemistry may be useful factors allowing us to predict the intensity of plant‐soil feedback in the system.