PlantSoilAdapt - Evolutsioonilised muutused taimede ja mulla vahelistes interaktsioonides maakasutuse muutudes: tagajärjed mulla funktsioneerimisele ja põuakindlusele

Selle kollektsiooni püsiv URIhttps://hdl.handle.net/10062/105254

Projekt uurib kuidas evolutsioonilised muutused taimede ja mulla vahelistes interaktsioonides maakasutuse muutudes mõjutavad mulla funktsioneerimist ja rohumaade põuakindlust.

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Plant phylogeny, traits and fungal community composition asdrivers of plant–soil feedbacks
(2025) J. Sweeney, Christopher; Semchenko, Marina; de Vries, Franciska T.; van Dongen, Bart E.; Bardgett, Richard D.
Plant–soil feedbacks (PSFs) are key drivers of plant community dynamics. However, our understanding of the factors moderating PSFs remains limited. We examined how plant phylogenetic relatedness and functional traits determine PSFs via their influence on rhizosphere fungal communities, especially arbuscular mycorrhizal fungi (AMF) and fungal pathotrophs. We conducted a glasshouse PSF experiment using 21 temperate grassland plant species, where each focal species was exposed to soils conditioned by heterospecific plants of increasing phylogenetic dissimilarity. We tested whether phylogenetic distance between plant species, functional traits or the degree to which species associate with AMF or fungal pathotrophs, explained the magnitude and direction of PSF responses. None of the measured plant traits explained PSFs, although the relative abundance of AMF was weakly and positively related to PSFs. Across all plant species, phylogenetic relatedness did not explain PSFs. However, species-specific effects of phylogenetic relatedness on the outcome of PSFs were detected. In particular, significant relationships with phylogenetic relatedness were observed only for species characterised by the highest rhizosphere relative abundance of AMF or fungal pathotrophs. For Centaurea nigra and Vicia cracca (both high AMF abundance) and Anthoxanthum odoratum (high pathotroph abundance), we found that PSF became more positive with increased phylogenetic distance between focal and conditioning species, showing a shift towards increased performance in conspecific than heterospecific soils. Meanwhile, as phylogenetic dissimilarity between Poa trivialis (high pathotroph abundance) and the soil conditioning species increased, more negative PSFs were observed, indicating improved performance in soils conditioned by increasingly distant heterospecific species. Synthesis. Our results suggest that plant traits and phylogenetic relatedness are poor predictors of plant–soil feedbacks (PSFs) among temperate grassland plant species. Hence, despite known effects of these factors in shaping rhizosphere microbial communities, the way plant species respond to these microbial communities is not related to the same characteristics. The occurrence of significant relationships between phylogenetic distance and PSFs in species with high relative abundances of mycorrhizal or pathogenic fungi suggests that the tendency to accumulate fungal mutualists or pathotrophs may be an important moderator of the relationship between plant phylogenetic relatedness and the magnitude and direction of PSFs.
Plant mycorrhizal status indicates partner selectivity in arbuscular mycorrhizal interaction networks
(2024) Koorem, Kadri; Sepp, Siim-Kaarel; Bueno, C. Guillermo; Davison, John; Liu, Siqiao; Meng, Yiming; Semchenko, Marina; Vasar, Martti; Zobel, Martin; Moora, Mari
Mycorrhizal symbiosis, specifically arbuscular mycorrhiza, is one of Earth's oldest and most widespread symbiosis. Existing evidence suggests that plant species differ in their associations with mycorrhizal partners, with different species reported to be always (obligately mycorrhizal, OM), sometimes (facultatively mycorrhizal, FM) or never (non-mycorrhizal, NM) associating with arbuscular mycorrhizal (AM) fungi and this plant reliance on AM fungi is called plant mycorrhizal status. However, very little is known about how host plant mycorrhizal status shapes the network topology of interacting AM fungi. Here, we use a standardized sampling scheme to test whether plant species with different mycorrhizal statuses differ in mean AM fungal hyphal colonization and various indices of the AM fungal networks such as nestedness rank and resource range. We collected the roots and rhizosphere soil of 19 plant species representing five families. Each plant species was sampled from three distinct habitats. We determined AM fungal colonization in the roots and AM fungal community composition in roots and rhizosphere soil using molecular methods. We found that previously reported NM plant species had lower mean AM fungal colonization than FM plant species, but no differences were found between FM and OM plant species. Network analyses indicated that AM fungal communities in the roots of FM plant species had higher nestedness rank and resource range than networks associated with OM plant species, suggesting that OM plant species are more generalist regarding partner selection and interact with a wider range of fungal partners. Our results suggest that plant mycorrhizal status conveys useful information about the characteristics of AM fungal interaction networks, revealing that plant species consistently associated with AM fungi are less selective towards their fungal partners.
Interactive effects of leaf pathogens and plant mycorrhizal type on plant diversity–productivity relationships
(2025) Xi, Nianxun; Zhao, Yansong; Semchenko, Marina
Diversity–productivity relationships can differ between forests dominated by different mycorrhizal types and be modulated by specialist and generalist pathogens. However, little is known about how these factors interact to modulate biodiversity effects. We addressed this knowledge gap with a 2-year experiment combining the manipulation of plant richness (one, two, four, eight species) and mycorrhizal tree type (arbuscular mycorrhizal [AM] tree-dominated; ecto-mycorrhizal [ECM] tree-dominated) with fungicide application for leaf pathogens (added or control). Biodiversity effects were quantified for community productivity and its two components (shoots and roots). We observed nonlinear diversity–productivity relationships, with the productivity of ECM tree-dominated communities increasing at low to intermediate diversity and declining at the highest species richness. Foliar fungicide application reduced positive complementarity effects and increased productivity in both ECM tree monocultures as well as eight-species mixtures. This finding suggests that the dilution effects of specialized pathogens may dominate at low diversity, while the spillover effects of generalist pathogens may become dominant at high diversity, resulting in unimodal diversity–productivity relationships. In AM tree-dominated communities, aboveground productivity strongly increased in response to leaf pathogen suppression in eight-species mixtures, and the release from leaf pathogens benefited most of the species that were most productive in fungicide-treated monocultures. This agrees with the prediction that spillover effects of generalist pathogens in diverse plant communities could differentially suppress highly productive species due to the trade-off between growth and defense. In addition, positive biodiversity effects on root production were significantly stronger in AM tree- than ECM tree-dominated communities. Our results demonstrate that relationships between plant diversity and productivity can be nonlinear due to the combined effects of specialized and generalized plant–fungal interactions, depend on plant mycorrhizal type, and differ between aboveground and belowground compartments.
Intraspecific plant–soil feedback in four tropical tree species is inconsistent in a field experiment
(2024) Eck, Jenalle L.; Hassan, Lourdes Hernández; Comita, Liza S.
Premise Soil microbes can influence patterns of diversity in plant communities via plant–soil feedbacks. Intraspecific plant–soil feedbacks occur when plant genotype leads to variations in soil microbial composition, resulting in differences in the performance of seedlings growing near their maternal plants versus seedlings growing near nonmaternal conspecific plants. How consistently such intraspecific plant–soil feedbacks occur in natural plant communities is unclear, especially in variable field conditions. Methods In an in situ experiment with four native tree species on Barro Colorado Island (BCI), Panama, seedlings of each species were transplanted beneath their maternal tree or another conspecific tree in the BCI forest. Mortality and growth were assessed at the end of the wet season (~4 months post-transplant) and at the end of the experiment (~7 months post-transplant). Results Differences in seedling performance among field treatments were inconsistent among species and eroded over time. Effects of field environment were detected at the end of the wet season in two of the four species: Virola surinamensis seedlings had higher survival beneath their maternal tree than other conspecific trees, while seedling survival of Ormosia macrocalyx was higher under other conspecific trees. However, these differences were gone by the end of the experiment. Conclusions Our results suggest that intraspecific plant–soil feedbacks may not be consistent in the field for tropical tree species and may have a limited role in determining seedling performance in tropical tree communities. Future studies are needed to elucidate the environmental and genetic factors that determine the incidence and direction of intraspecific plant–soil feedbacks in plant communities.
A trait-based framework linking the soil metabolome to plant–soil feedbacks
(2023) Delory, Benjamin M.; Callaway, Ragan M.; Semchenko, Marina
By modifying the biotic and abiotic properties of the soil, plants create soil legacies that can affect vegetation dynamics through plant–soil feedbacks (PSF). PSF are generally attributed to reciprocal effects of plants and soil biota, but these interactions can also drive changes in the identity, diversity and abundance of soil metabolites, leading to more or less persistent soil chemical legacies whose role in mediating PSF has rarely been considered. These chemical legacies may interact with microbial or nutrient legacies to affect species coexistence. Given the ecological importance of chemical interactions between plants and other organisms, a better understanding of soil chemical legacies is needed in community ecology. In this Viewpoint, we aim to: highlight the importance of belowground chemical interactions for PSF; define and integrate soil chemical legacies into PSF research by clarifying how the soil metabolome can contribute to PSF; discuss how functional traits can help predict these plant–soil interactions; propose an experimental approach to quantify plant responses to the soil solution metabolome; and describe a testable framework relying on root economics and seed dispersal traits to predict how plant species affect the soil metabolome and how they could respond to soil chemical legacies.
Symbiont plasticity as a driver of plant success
(2024) Zobel, Martin; Koorem, Kadri; Moora, Mari; Semchenko, Marina; Davison, John
We discuss which plant species are likely to become winners, that is achieve the highest global abundance, in changing landscapes, and whether plant-associated microbes play a determining role. Reduction and fragmentation of natural habitats in historic landscapes have led to the emergence of patchy, hybrid landscapes, and novel landscapes where anthropogenic ecosystems prevail. In patchy landscapes, species with broad niches are favoured. Plasticity in the degree of association with symbiotic microbes may contribute to broader plant niches and optimization of symbiosis costs and benefits, by downregulating symbiosis when it is unnecessary and upregulating it when it is beneficial. Plasticity can also be expressed as the switch from one type of mutualism to another, for example from nutritive to defensive mutualism with increasing soil fertility and the associated increase in parasite load. Upon dispersal, wide mutualistic partner receptivity is another facet of symbiont plasticity that becomes beneficial, because plants are not limited by the availability of specialist partners when arriving at new locations. Thus, under conditions of global change, symbiont plasticity allows plants to optimize the activity of mutualistic relationships, potentially allowing them to become winners by maximizing geographic occupancy and local abundance.

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