BACKGROUND AND AIMS: Polyploidy is an important driver of plant diversification and adaptation to novel environments. As a consequence of genome doubling, polyploids often exhibit greater colonizing ability or occupy a wider ecological niche than diploids. Although elevation has been traditionally considered as a key driver structuring ploidy variation, we do not know if environmental and phenotypic differentiation among ploidy cytotypes varies along an elevational gradient. Here, we tested for the consequences of genome duplication on genetic diversity, phenotypic variation and habitat preferences on closely related diploid and tetraploid populations that coexist along approx. 2300 m of varying elevation. METHODS: We sampled and phenotyped 45 natural diploid and tetraploid populations of Arabidopsis arenosa in one mountain range in Central Europe (Western Carpathians) and recorded abiotic and biotic variables at each collection site. We inferred genetic variation, population structure and demographic history in a sub-set of 29 populations genotyped for approx. 36 000 single nucleotide polymorphisms. KEY RESULTS: We found minor effects of polyploidy on colonization of alpine stands and low genetic differentiation between the two cytotypes, mirroring recent divergence of the polyploids from the local diploid lineage and repeated reticulation events among the cytotypes. This pattern was corroborated by the absence of ecological niche differentiation between the two cytotypes and overall phenotypic similarity at a given elevation. CONCLUSIONS: The case of A. arenosa contrasts with previous studies that frequently showed clear niche differentiation between cytotypes. Our work stresses the importance of considering genetic structure and past demographic processes when interpreting the patterns of ploidy distributions, especially in species that underwent recent polyploidization events.

• Klíčová slova
• Arabidopsis arenosa, Alpine adaptation, RAD-sequencing, genetic variation, multivariate statistics, niche differentiation, polyploidy,
• MeSH
• Arabidopsis * MeSH
• ekosystém MeSH
• lidé MeSH
• ploidie MeSH
• polyploidie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Evropa MeSH

BACKGROUND AND AIMS: The origin of different cytotypes by autopolyploidy may be an important mechanism in plant diversification. Although cryptic autopolyploids probably comprise the largest fraction of overlooked plant diversity, our knowledge of their origin and evolution is still rather limited. Here we study the presumed autopolyploid aggregate of Aster amellus, which encompasses diploid and hexaploid cytotypes. Although the cytotypes of A. amellus are not morphologically distinguishable, previous studies showed spatial segregation and limited gene flow between them, which could result in different evolutionary trajectories for each cytotype. METHODS: We combine macroevolutionary, microevolutionary and niche modelling tools to disentangle the origin and the demographic history of the cytotypes, using chloroplast and nuclear markers in a dense population sampling in central Europe. KEY RESULTS: Our results revealed a segregation between diploid and hexaploid cytotypes in the nuclear genome, where each cytotype represents a monophyletic lineage probably homogenized by concerted evolution. In contrast, the chloroplast genome showed intermixed connections between the cytotypes, which may correspond to shared ancestral relationships. Phylogeny, demographic analyses and ecological niche modelling supported an ongoing differentiation of the cytotypes, where the hexaploid cytotype is experiencing a demographic expansion and niche differentiation with respect to its diploid relative. CONCLUSIONS: The two cytotypes may be considered as two different lineages at the onset of their evolutionary diversification. Polyploidization led to the occurrence of hexaploids, which expanded and changed their ecological niche.

• MeSH
• Aster genetika   MeSH
• biologická evoluce * MeSH
• biologické modely MeSH
• DNA chloroplastová analýza   MeSH
• fylogeneze * MeSH
• fylogeografie MeSH
• genetické markery MeSH
• mezerníky ribozomální DNA analýza   MeSH
• polyploidie * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Evropa MeSH
• Názvy látek
• DNA chloroplastová MeSH
• genetické markery MeSH
• mezerníky ribozomální DNA MeSH

Plant-soil feedback (PSF) is a fundamental mechanism explaining plant community composition. Two-phase experiments, i.e., conditioning and feedback, represent a common methodology to study PSF. The duration of the conditioning phase varies among studies and the PSF observed is often explained by its biotic component. Little is known about the temporal variation of PSF and its abiotic component. As early life stages are crucial for plant establishment, we grew Rorippa austriaca in soil conditioned over 2, 4, 6 or 8 weeks by a conspecific or a co-occurring species, Agrostis capillaris. For each conditioning duration, we analysed the soil chemical properties and the direction and intensity of intra- or inter-specific feedbacks. With increasing duration, the negative intra- and inter-specific feedbacks became stronger and weaker, respectively. The inter-specific feedback was more negative than the intra-specific feedback at 2 weeks and this reversed thereafter. The Mg content decreased with conditioning duration whatever the conditioning species was. With increasing duration, conditioning by R. austriaca strongly decreased pH, while A. capillaris did not affect pH. The K and P contents were not affected by the conditioning duration and were higher in R. austriaca soil than in A. capillaris soil. Our results suggest that not only conditioning species but also duration of conditioning phase may affect the magnitude of PSF. The changes in soil chemical properties linked to the conditioning species or the conditioning phase duration may drive the feedbacks by affecting plant growth directly or via the interacting microbial communities.

• Klíčová slova
• Brassicaceae, Conditioning, Native species, Negative feedback, Plant-soil feedback indices,
• MeSH
• půda * MeSH
• půdní mikrobiologie MeSH
• rostliny * MeSH
• vývoj rostlin MeSH
• zpětná vazba MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• půda * MeSH

Vicia cracca diploids and autotetraploids are highly parapatric in Europe; tetraploids reside in western and northern part, whereas diploids occupy much drier south-eastern part. They meet together in a Central European contact zone. This distribution pattern raised questions about a transformative effect of polyploidization on plant performance and environmental tolerances. We investigated plant survival, growth, and seed production in two water regimes in a common garden experiment using seeds collected from five localities in the Central European contact zone where diploids and tetraploids occur in sympatry. Obtained data imply that tetraploids of V. cracca are not generally superior in performance to diploids. Significantly larger seeds from tetraploid mother plants collected in the field were not correlated with greater stature of the seedlings. Nonetheless, tetraploids might have a potential to out-compete diploids in the long run due to the tetraploids' ability of greater growth which manifested in the second year of cultivation. Considering the response of diploids and tetraploids to water supply, drought stressed tetraploids but not diploids produced a higher proportion of aborted seeds than watered ones, which implies that tetraploids are more drought susceptible than diploids. On the other hand, decreased plant height in drought stresses tetraploids, which simultaneously increased total seed production, may suggest that tetraploids have a greater ability to avoid local extinction under unfavourable conditions by enhancing biomass allocation into production of seeds at the cost of lower growth. The significant interaction between ploidy level and locality in several traits suggests possible polyfyletic origin of tetraploids and the necessity to clarify the history of the tetraploids in Europe.

• Klíčová slova
• Drought stress, Polyploid, Seed production, Seed weight, Sympatric, Vegetative growth,
• MeSH
• biomasa MeSH
• diploidie MeSH
• ploidie MeSH
• semena rostlinná genetika   růst a vývoj   MeSH
• semenáček genetika   růst a vývoj   MeSH
• sympatrie MeSH
• tetraploidie MeSH
• vikev genetika   růst a vývoj   MeSH
• zahrady MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Evropa MeSH

Areas of immediate contact of different cytotypes offer a unique opportunity to study evolutionary dynamics within heteroploid species and to assess isolation mechanisms governing coexistence of cytotypes of different ploidy. The degree of reproductive isolation of cytotypes, that is, the frequency of heteroploid crosses and subsequent formation of viable and (partly) fertile hybrids, plays a crucial role for the long-term integrity of lineages in contact zones. Here, we assessed fine-scale distribution, spatial clustering, and ecological niches as well as patterns of gene flow in parental and hybrid cytotypes in zones of immediate contact of di-, tetra-, and hexaploid Senecio carniolicus (Asteraceae) in the Eastern Alps. Cytotypes were spatially separated also at the investigated microscale; the strongest spatial separation was observed for the fully interfertile tetra- and hexaploids. The three main cytotypes showed highly significant niche differences, which were, however, weaker than across their entire distribution ranges in the Eastern Alps. Individuals with intermediate ploidy levels were found neither in the diploid/tetraploid nor in the diploid/hexaploid contact zones indicating strong reproductive barriers. In contrast, pentaploid individuals were frequent in the tetraploid/hexaploid contact zone, albeit limited to a narrow strip in the immediate contact zone of their parental cytotypes. AFLP fingerprinting data revealed introgressive gene flow mediated by pentaploid hybrids from tetra- to hexaploid individuals, but not vice versa. The ecological niche of pentaploids differed significantly from that of tetraploids but not from hexaploids.

• Klíčová slova
• Asymmetric gene flow, Senecio carniolicus (Asteraceae), contact zone, ecological niche, hybrid cytotypes, polyploidy,
• Publikační typ
• časopisecké články MeSH

Due to increased levels of heterozygosity, polyploids are expected to have a greater ability to adapt to different environments than their diploid ancestors. While this theoretical pattern has been suggested repeatedly, studies comparing adaptability to changing conditions in diploids and polyploids are rare. The aim of the study was to determine the importance of environmental conditions of origin as well as target conditions on performance of two Anthericum species, allotetraploid A. liliago and diploid A. ramosum and to explore whether the two species differ in the ability to adapt to these environmental conditions. Specifically, we performed a common garden experiment using soil from 6 localities within the species' natural range, and we simulated the forest and open environments in which they might occur. We compared the performance of diploid A. ramosum and allotetraploid A. liliago originating from different locations in the different soils. The performance of the two species was not affected by simulated shading but differed strongly between the different target soils. Growth of the tetraploids was not affected by the origin of the plants. In contrast, diploids from the most nutrient poor soil performed best in the richest soil, indicating that diploids from deprived environments have an increased ability to acquire nutrients when available. They are thus able to profit from transfer to novel nutrient rich environments. Therefore, the results of the study did not support the general expectation that the polyploids should have a greater ability than the diploids to adapt to a wide range of conditions. In contrast, the results are in line with the observation that diploids occupy a wider range of environments than the allotetraploids in our system.

• MeSH
• diploidie MeSH
• ekosystém MeSH
• fyziologická adaptace * MeSH
• liliovité klasifikace   genetika   fyziologie   MeSH
• polyploidie MeSH
• půda chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• půda MeSH

Many plant populations have adapted to local soil conditions. However, the role of arbuscular mycorrhizal fungi is often overlooked in this context. Only a few studies have used reciprocal transplant experiments to study the relationships between soil conditions, mycorrhizal colonisation and plant growth. Furthermore, most of the studies were conducted under controlled greenhouse conditions. However, long-term field experiments can provide more realistic insights into this issue. We conducted a five-year field reciprocal transplant experiment to study the relationships between soil conditions, arbuscular mycorrhizal fungi and plant growth in the obligate mycotrophic herb Aster amellus. We conducted this study in two regions in the Czech Republic that differ significantly in their soil nutrient content, namely Czech Karst (region K) and Ceske Stredohori (region S). Plants that originated from region S had significantly higher mycorrhizal colonisation than plants from region K, indicating that the percentage of mycorrhizal colonisation has a genetic basis. We found no evidence of local adaptation in Aster amellus. Instead, plants from region S outperformed the plants from region K in both target regions. Similarly, plants from region S showed more mycorrhizal colonisation in all cases, which was likely driven by the lower nutrient content in the soil from that region. Thus, plant aboveground biomass and mycorrhizal colonisation exhibited corresponding differences between the two target regions and regions of origin. Higher mycorrhizal colonisation in the plants from region with lower soil nutrient content (region S) in both target regions indicates that mycorrhizal colonisation is an adaptive trait. However, lower aboveground biomass in the plants with lower mycorrhizal colonisation suggests that the plants from region K are in fact maladapted by their low inherent mycorrhizal colonization. We conclude that including mycorrhizal symbiosis in local adaptation studies may increase our understanding of the mechanisms by which plants adapt to their environment.

• MeSH
• aklimatizace fyziologie   MeSH
• Aster fyziologie   MeSH
• kořeny rostlin MeSH
• mykorhiza růst a vývoj   MeSH
• půdní mikrobiologie MeSH
• symbióza fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH

The potential for gene exchange across ploidy levels has long been recognized, but only a few studies have explored the rate of gene flow among different cytotypes. In addition, most of the existing knowledge comes from contact zones between diploids and tetraploids. The purpose of this paper was to investigate relationships between diploid and hexaploid individuals within the Aster amellus aggregate. A. amellus is known to occur in diploid and hexaploid cytotypes in Europe, with a complex contact zone in central Europe. Patterns of genetic diversity were investigated using seven microsatellite loci at three different spatial scales: (1) in the single known mixed-ploidy population; (2) in populations at the contact zone and (3) in a wider range of populations across Europe. The results show clear separation of the cytotypes at all three spatial scales. In addition, analysis of molecular variance strongly supported a model predicting a single origin of the hexaploids, with no or very limited gene flow between the cytotypes. Some hexaploid individuals found in the mixed-ploidy population, however, fell into the diploid cluster. This could suggest recurrent polyploid formation or occasional cross-pollination between cytotypes; however, there are strong post-zygotic breeding barriers between the two cytotypes, making the latter less plausible. Overall, the results suggest that the cytotypes could represent two cryptic species. Nevertheless, their formal separation is difficult as they cannot be distinguished morphologically, occupy very similar habitat conditions and have largely overlapping distribution ranges. These results show that polyploid complexes must be treated with caution as they can hide biological diversity and can have different adaptation potentials, evolving independently.

• MeSH
• analýza hlavních komponent MeSH
• Aster genetika   MeSH
• Bayesova věta MeSH
• diploidie * MeSH
• fylogeografie MeSH
• genetická variace MeSH
• mikrosatelitní repetice MeSH
• modely genetické MeSH
• polyploidie * MeSH
• rostlinné geny MeSH
• tok genů * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Evropa MeSH