Arbuscular mycorrhizal fungi (AMF) represent an important soil microbial group playing a fundamental role in many terrestrial ecosystems. We explored the effects of deterministic (soil characteristics, host plant life stage, neighbouring plant communities) and stochastic processes on AMF colonization, richness and community composition in roots of Knautia arvensis (Dipsacaceae) plants from three serpentine grasslands and adjacent nonserpentine sites. Methodically, the study was based on 454-sequencing of the ITS region of rDNA. In total, we detected 81 molecular taxonomical operational units (MOTUs) belonging to the Glomeromycota. Serpentine character of the site negatively influenced AMF root colonization, similarly as higher Fe concentration. AMF MOTUs richness linearly increased along a pH gradient from 3.5 to 5.8. Contrary, K and Cr soil concentration had a negative influence on AMF MOTUs richness. We also detected a strong relation between neighbouring plant community composition and AMF MOTUs richness. Although spatial distance between the sampled sites (c. 0.3-3 km) contributed to structuring AMF communities in K. arvensis roots, environmental parameters were key factors in this respect. In particular, the composition of AMF communities was shaped by the complex of serpentine conditions, pH and available soil Ni concentration. The composition of AMF communities was also dependent on host plant life stage (vegetative vs. generative). Our study supports the dominance of deterministic factors in structuring AMF communities in heterogeneous environment composed of an edaphic mosaic of serpentine and nonserpentine soils.
- MeSH
- Dipsacaceae mikrobiologie MeSH
- DNA fungální genetika MeSH
- ekosystém * MeSH
- fylogeneze MeSH
- kořeny rostlin mikrobiologie MeSH
- mezerníky ribozomální DNA genetika MeSH
- mykorhiza klasifikace genetika MeSH
- pastviny * MeSH
- půda chemie MeSH
- půdní mikrobiologie * MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Serpentine soils have naturally elevated concentrations of certain heavy metals, including nickel. This study addressed the role of plant origin (serpentine vs. non-serpentine) and symbiosis with arbuscular mycorrhizal fungi (AMF) in plant Ni tolerance. A semi-hydroponic experiment involving three levels of Ni and serpentine and non-serpentine AMF isolates and populations of a model plant species (Knautia arvensis) revealed considerable negative effects of elevated Ni availability on both plant and fungal performance. Plant growth response to Ni was independent of edaphic origin; however, higher Ni tolerance of serpentine plants was indicated by a smaller decline in the concentrations of photosynthetic pigments and restricted root-to-shoot Ni translocation. Serpentine plants also retained relatively more Mg in their roots, resulting in a higher shoot Ca/Mg ratio. AMF inoculation, especially with the non-serpentine isolate, further aggravated Ni toxicity to host plants. Therefore, AMF do not appear to be involved in Ni tolerance of serpentine K. arvensis plants.
Many recent studies have explored the effects of present and past landscape structure on species distribution and diversity. However, we know little about the effects of past landscape structure on distribution of genetic diversity within and between populations of a single species. Here we describe the relationship between present and past landscape structure (landscape connectivity and habitat size estimated from historical maps) and current genetic structure in a perennial herb, Succisa pratensis. We used allozymes as co-dominant markers to estimate genetic diversity and deviation from Hardy-Weinberg equilibrium in 31 populations distributed within a 5 km(2) agricultural landscape. The results showed that current genetic diversity of populations was related to habitat suitability, habitat age, habitat size and habitat connectivity in the past. The effects of habitat age and past connectivity on genetic diversity were in most cases also significant after taking the current landscape structure into account. Moreover, current genetic similarity between populations was affected by past connectivity after accounting for current landscape structure. In both cases, the oldest time layer (1850) was the most informative. Most populations showed heterozygote excess, indicating disequilibrium due to recent gene flow or selection against homozygotes. These results suggest that habitat age and past connectivity are important determinants of distribution of genetic diversity between populations at a scale of a few kilometres. Landscape history may significantly contribute to our understanding of distribution of current genetic structure within species and the genetic structure may be used to better understand landscape history, even at a small scale.
- MeSH
- alely MeSH
- Dipsacaceae genetika MeSH
- ekosystém * MeSH
- genetická variace * MeSH
- genetické markery genetika MeSH
- genetické struktury * MeSH
- heterozygot MeSH
- inbreeding MeSH
- izoenzymy genetika MeSH
- populační genetika * MeSH
- regresní analýza MeSH
- rostlinné proteiny genetika MeSH
- selekce (genetika) MeSH
- tok genů MeSH
- životní prostředí MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Arbuscular mycorrhizal (AM) symbiosis is among the factors contributing to plant survival in serpentine soils characterised by unfavourable physicochemical properties. However, AM fungi show a considerable functional diversity, which is further modified by host plant identity and edaphic conditions. To determine the variability among serpentine AM fungal isolates in their effects on plant growth and nutrition, a greenhouse experiment was conducted involving two serpentine and two non-serpentine populations of Knautia arvensis plants grown in their native substrates. The plants were inoculated with one of the four serpentine AM fungal isolates or with a complex AM fungal community native to the respective plant population. At harvest after 6-month cultivation, intraradical fungal development was assessed, AM fungal taxa established from native fungal communities were determined and plant growth and element uptake evaluated. AM symbiosis significantly improved the performance of all the K. arvensis populations. The extent of mycorrhizal growth promotion was mainly governed by nutritional status of the substrate, while the effect of AM fungal identity was negligible. Inoculation with the native AM fungal communities was not more efficient than inoculation with single AM fungal isolates in any plant population. Contrary to the growth effects, a certain variation among AM fungal isolates was revealed in terms of their effects on plant nutrient uptake, especially P, Mg and Ca, with none of the AM fungi being generally superior in this respect. Regardless of AM symbiosis, K. arvensis populations significantly differed in their relative nutrient accumulation ratios, clearly showing the plant's ability to adapt to nutrient deficiency/excess.
- MeSH
- biomasa MeSH
- Dipsacaceae růst a vývoj mikrobiologie fyziologie MeSH
- fylogeneze MeSH
- houby klasifikace izolace a purifikace fyziologie MeSH
- molekulární sekvence - údaje MeSH
- mykorhiza klasifikace izolace a purifikace fyziologie MeSH
- očkovadla agrotechnická klasifikace genetika izolace a purifikace fyziologie MeSH
- půda chemie MeSH
- symbióza MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Polyploidization is one of the leading forces in the evolution of land plants, providing opportunities for instant speciation and rapid gain of evolutionary novelties. Highly selective conditions of serpentine environments act as an important evolutionary trigger that can be involved in various speciation processes. Whereas the significance of both edaphic speciation on serpentine and polyploidy is widely acknowledged in plant evolution, the links between polyploid evolution and serpentine differentiation have not yet been examined. To fill this gap, we investigated the evolutionary history of the perennial herb Knautia arvensis (Dipsacaceae), a diploid-tetraploid complex that exhibits an intriguing pattern of eco-geographic differentiation. Using plastid DNA sequencing and AFLP genotyping of 336 previously cytotyped individuals from 40 populations from central Europe, we unravelled the patterns of genetic variation among the cytotypes and the edaphic types. Diploids showed the highest levels of genetic differentiation, likely as a result of long term persistence of several lineages in ecologically distinct refugia and/or independent immigration. Recurrent polyploidization, recorded in one serpentine island, seems to have opened new possibilities for the local serpentine genotype. Unlike diploids, the serpentine tetraploids were able to escape from the serpentine refugium and spread further; this was also attributable to hybridization with the neighbouring non-serpentine tetraploid lineages. The spatiotemporal history of K. arvensis allows tracing the interplay of polyploid evolution and ecological divergence on serpentine, resulting in a complex evolutionary pattern. Isolated serpentine outcrops can act as evolutionary capacitors, preserving distinct karyological and genetic diversity. The serpentine lineages, however, may not represent evolutionary 'dead-ends' but rather dynamic systems with a potential to further influence the surrounding populations, e.g., via independent polyplodization and hybridization. The complex eco-geographical pattern together with the incidence of both primary and secondary diploid-tetraploid contact zones makes K. arvensis a unique system for addressing general questions of polyploid research.
- MeSH
- analýza polymorfismu délky amplifikovaných restrikčních fragmentů MeSH
- biologická evoluce * MeSH
- chrysotilový azbest MeSH
- Dipsacaceae genetika metabolismus MeSH
- ekosystém MeSH
- fenotyp MeSH
- fylogeneze MeSH
- genom rostlinný MeSH
- haplotypy MeSH
- plastidy genetika MeSH
- polyploidie * MeSH
- půda chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Evropa MeSH
- MeSH
- Chelidonium MeSH
- Colchicum MeSH
- Dipsacaceae MeSH
- léčivé rostliny MeSH
- lidé MeSH
- nádory terapie MeSH
- protinádorové látky MeSH
- Check Tag
- lidé MeSH
