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Whilst transgenerational effects (TGE) of abiotic conditions are becoming generally accepted in plants, those of biotic interactions remain largely unexplored. We therefore investigated the influence of TGE due to arbuscular mycorrhiza, the most widespread mutualistic interaction of plants with microorganisms, on clonal and sexual offspring of Fragaria vesca. We hypothesized that the ecological and evolutionary significance of TGE will vary between clonal and sexual offspring based on mycorrhizal status and phosphorus (P) availability experienced by the parent. In a two‐generation greenhouse experiment, parental plants were exposed to full‐factorial combinations of mycorrhizal status and high or low P availability. TGE on mycorrhiza establishment and plant performance were evaluated in their clonal and sexual offspring, which experienced the parental or all non‐parental environments. Consistently in both generations, mycorrhiza improved plant growth at low P availability, but had no or even negative effect at high P availability, concomitantly with decreased root colonization by the arbuscular mycorrhizal (AM) fungus. TGE due to mycorrhiza was generally stronger in sexually derived offspring, both on mycorrhiza formation and plant growth. In sexual offspring, parental mycorrhizal status was adaptive if the offspring's mycorrhizal status was of disadvantage: for mycorrhizal offspring growing in high P availability and for non‐mycorrhizal offspring at low P availability. Synthesis: Our results suggest that clonal and sexual reproduction are under different evolutionary pressures, leading to the development of stronger TGE mechanisms in response to mycorrhizal symbiosis in the latter. The complexity of the observed effects highlights the need for disentangling the mechanisms contributing to the TGE in clonal and sexual reproduction. Our study underlines the importance of considering reproductive strategies and the interplay between environmental factors and TGE in understanding the ecological and evolutionary dynamics of plant–symbiotic interactions. [ABSTRACT FROM AUTHOR]

Summary: Due to the accelerating climate change, it is crucial to understand how plants adapt to rapid environmental changes. Such adaptation may be mediated by epigenetic mechanisms like DNA methylation, which could heritably alter phenotypes without changing the DNA sequence, especially across clonal generations. However, we are still missing robust evidence of the adaptive potential of DNA methylation in wild clonal populations.Here, we studied genetic, epigenetic and transcriptomic variation of Fragaria vesca, a predominantly clonally reproducing herb. We examined samples from 21 natural populations across three climatically distinct geographic regions, as well as clones of the same individuals grown in a common garden.We found that epigenetic variation was partly associated with climate of origin, particularly in non‐CG contexts. Importantly, a large proportion of this variation was heritable across clonal generations. Additionally, a subset of these epigenetic changes affected the expression of genes mainly involved in plant growth and responses to pathogen and abiotic stress. These findings highlight the potential influence of epigenetic changes on phenotypic traits.Our findings indicate that variation in DNA methylation, which can be environmentally inducible and heritable, may enable clonal plant populations to adjust to their environmental conditions even in the absence of genetic adaptation. [ABSTRACT FROM AUTHOR]

An accumulating body of evidence indicates that natural plant populations harbour a large diversity of transposable elements (TEs). TEs, which are especially mobilized under genomic and/or environmental stress, provide genetic and epigenetic variation that can substantially translate into a diversity of plant phenotypes within populations. However, it remains unclear what the potential ecological effects of diversity in TEs within an otherwise genetically uniform population are in terms of phenotypic diversity's effects on coexistence and ecosystem functioning.Using Arabidopsis thaliana as a proof‐of‐concept model, we assembled populations from individuals differing in the number and positions of ONSEN retrotransposon and tested whether the increasing diversity created by the ONSEN retrotransposon increased the phenotypic diversity of populations and enhanced their functioning under different environmental conditions.We demonstrate that TE‐generated variation creates differentiation in ecologically important traits connected to different axes of the plant 'economics' spectrum. In particular, we show that Arabidopsis populations with increasing diversity of individuals differing in the ONSEN retrotransposon had higher phenotypic and functional diversity in resource use‐related traits. Such increased diversity enhanced population productivity and reduced the performance of interspecific competitors.Synthesis. We conclude that TE‐generated phenotypic and functional diversity can have similar effects on ecosystems as are usually documented for other biological diversity effects. The results of our experiment open up new fields of investigation, highlighting the ecological relevance of unexplored sources of phenotypic variability and hopefully inspiring functional trait ecologists and evolutionary biologists to begin exploring new questions at the intersection of their fields. [ABSTRACT FROM AUTHOR]

Summary: The phenotypes of plants can be influenced by the environmental conditions experienced by their parents. However, there is still much uncertainty about how common and how predictable such parental environmental effects really are.We carried out a comprehensive experimental test for parental effects, subjecting plants of multiple Arabidopsis thaliana genotypes to 24 different biotic or abiotic stresses, or combinations thereof, and comparing their offspring phenotypes in a common environment.The majority of environmental stresses caused significant parental effects, with −35% to +38% changes in offspring fitness. The expression of parental effects was strongly genotype‐dependent, and multiple environmental stresses often acted nonadditively when combined. The direction and magnitude of parental effects were unrelated to the direct effects on the parents: Some environmental stresses did not affect the parents but caused substantial effects on offspring, while for others, the situation was reversed.Our study demonstrates that parental environmental effects are common and often strong in A. thaliana, but they are genotype‐dependent, act nonadditively, and are difficult to predict. We should thus be cautious with generalizing from simple studies with single plant genotypes and/or only few individual environmental stresses. A thorough and general understanding of parental effects requires large multifactorial experiments. [ABSTRACT FROM AUTHOR]

Stress can be remembered by plants in a form of stress legacy that can alter future phenotypes of previously stressed plants and even phenotypes of their offspring. DNA methylation belongs among the mechanisms mediating the stress legacy. It is however not known for how long the stress legacy is carried by plants. If the legacy is long‐lasting, it can become maladaptive in situations when parental–offspring environment do not match. We investigated for how long after the last exposure of a parental plant to drought can the phenotype of its clonal offspring be altered. We grew parental plants of three genotypes of Trifolium repens for five months either in control conditions or in control conditions that were interrupted with intense drought periods applied for two months in four different time slots. We also treated half of the parental plants with a demethylating agent (5‐azacytidine, 5‐azaC) to test for the potential role of DNA methylation in the stress memory. Then, we transplanted parental cuttings (ramets) individually to control environment and allowed them to produce offspring ramets for two months. The drought stress experienced by parents affected phenotypes of offspring ramets. The stress legacy resulted in enhanced number of offspring ramets originating from plants that experienced drought stress even 56 days before their transplantation to the control environment. 5‐azaC altered transgenerational effects on offspring ramets. We confirmed that drought stress can trigger transgenerational effects in T. repens that is very likely mediated by DNA methylation. Most importantly, the stress legacy in parental plants persisted for at least 8 weeks suggesting that the stress legacy can persist in a clonal plant Trifolium repens for relatively long period. We suggest that the stress legacy should be considered in future ecological studies on clonal plants. [ABSTRACT FROM AUTHOR]

Many plant species protect themselves against herbivores through mechanical or chemical so‐called inducible defences (ID). These are regulated via a hormonal cascade which may be under epigenetic control and in which jasmonic acid (JA) plays a prominent role. In this study, we indirectly tested the role of DNA methylation in the production of ID and the synthesis of hormones involved in the ID signalling cascade. Using different intensities of 5‐azacytidine application, we aimed to produce plants of Trifolium repens with different levels of DNA methylation alteration. We then elicited the plants together with controls, i.e. plants with natural DNA methylation status, with JA and then indirectly recorded ID production in herbivore‐choice trials in which the leaves of plants with different DNA methylation statuses were provided to caterpillars of a generalist herbivore, Spodoptera littoralis. We also analysed the balance of several key defence hormones such as jasmonates, abscisic acid (ABA), indole‐3‐acetic acid (IAA) and salicylic acid in the plants. We found that the S. littoralis preferred demethylated plants over non‐demethylated controls. Demethylation also reduced production of JA, ABA and IAA. We conclude that DNA methylation modulates expression of ID likely via regulation of signalling hormones involved in the establishment of defence. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Abstract: Experimental demethylation of plant DNA enables testing for epigenetic effects in a simple and straightforward way without the use of expensive and laborious DNA sequencing. Plants are commonly demethylated during their germination with the application of agents such as 5‐azacytidine (5‐azaC). However, this approach can cause unwanted effects such as underdeveloped root systems and high mortality of treated plants, hindering a full comparison with untreated plants, and can be applied only on plant reproducing by seeds. Here we test a simple alternative method of plant demethylation designed to overcome the shortcomings of the germinating method. We compared a novel method of demethylating plants, based on periodical spraying of 5‐azaC aqueous solution on established seedlings, with the previous method in which seeds were germinated directly in 5‐azaC solution. We quantified the amount of methylated DNA and measured various aspects of plant performance. Also, we demonstrated its applicability in ecological epigenetic experiments by testing transgenerational effects of plant–plant competition. We found that the spray application had similar DNA‐demethylating efficiency than the germination method, particularly in the earlier phases of plant development, but without unwanted effects. The spray application method did not reduce plant growth and performance compared to untreated plants, as opposed to the traditional method which showed reduced growth. Also, the spray application method equalized the epigenetically modified plant features of seedlings coming from plants grown under competition and plants growing without competition, demonstrating its application in ecological epigenetic experiments. We conclude that regular spraying of 5‐azaC solution onto established seedlings surpassed the germination‐in‐solution method in terms of vigour and fitness of treated plants. This novel method could thus be better suited for experimental studies seeking valuable insights into ecological epigenetics. Furthermore, the spray method can be suitable for clonal species reproducing asexually, and most importantly, it opens the possibility of community‐level experimental demethylation of plants. [ABSTRACT FROM AUTHOR]

Growing evidence shows that epigenetic mechanisms contribute to complex traits, with implications across many fields of biology. In plant ecology, recent studies have attempted to merge ecological experiments with epigenetic analyses to elucidate the contribution of epigenetics to plant phenotypes, stress responses, adaptation to habitat, and range distributions. While there has been some progress in revealing the role of epigenetics in ecological processes, studies with non-model species have so far been limited to describing broad patterns based on anonymous markers of DNA methylation. In contrast, studies with model species have benefited from powerful genomic resources , which contribute to a more mechanistic understanding but have limited ecological realism. Understanding the significance of epigenetics for plant ecology requires increased transfer of knowledge and methods from model species research to genomes of evolutionarily divergent species, and examination of responses to complex natural environments at a more mechanistic level. This requires transforming genomics tools specifically for studying non-model species, which is challenging given the large and often polyploid genomes of plants. Collaboration among molecular geneticists, ecologists and bioinformaticians promises to enhance our understanding of the mutual links between genome function and ecological processes. [ABSTRACT FROM AUTHOR]

PREMISE OF THE study: The phenotype of an individual can be modified by the environment experienced by its predecessors, a phenomenon called trans-generational or maternal effects. These effects are studied mostly across sexual generations and are thought to be mediated also by epigenetic variation. However, we do not know how important transgenerational effects are across asexual generations of clonal plants. METHODS: We investigated the role of different drought intensities and durations experienced by parental plants of Trifolium repens on the growth of offspring ramets after transplantation of clonal cuttings to control conditions. We also treated half of the plants with 5-azacytidine, which is a demethylat-ing agent, to test the potential role of DNA methylation on transgenerational effects. KEY RESULTS: Transgenerational effects were manifested as increased biomass of offspring ramets if parental plants experienced medium drought applied for a short period and decreased biomass of offspring ramets if parental plants experienced intense drought for a short period. These transgenerational effects were not observed for offspring of parents from the same treatments if these were treated with 5-azacytidine, whose application significantly decreased the amount of 5-methyl-2'-deoxycytidine in plants. CONCLUSIONS: Transgenerational effects might play an important role in the clonal plant Trifolium repens and are probably mediated by epigenetic variation. The growth and behavior of clonal plants might be affected not only by the ambient environment but also by environments that are no longer present at the time of clonal reproduction. This phenomenon can have yet unacknowledged ecological and evolutionary implications for clonal plants. [ABSTRACT FROM AUTHOR]

Phenotypes of plants, and thus their ecology and evolution, can be affected by the environmental conditions experienced by their parents, a phenomenon called parental effects or transgenerational plasticity. However, whether such effects are just passive responses or represent a special type of adaptive plasticity remains controversial because of a lack of solid tests of their adaptive significance. Here, we investigated transgenerational effects of different nutrient environments on the productivity, carbon storage and flowering phenology of the perennial plant Plantago lanceolata, and whether these effects are influenced by seasonal variation in the maternal environment. We found that maternal environments significantly affected the offspring phenotype, and that plants consistently produced more biomass and had greater root carbohydrate storage if grown under the same environmental conditions as experienced by their mothers. The observed transgenerational effects were independent of the season in which seeds had matured. We therefore conclude that transgenerational effects on biomass and carbon storage in P. lanceolata are adaptive regardless of the season of seed maturation. [ABSTRACT FROM AUTHOR]

We assessed the role of nutrients and disturbance experienced by mothers (maternal effects) in the growth of progeny in a pot experiment using two Plantago species. Photosynthetic capacity, biomass allocation and fecundity were measured. Offspring of plants grown in nutrient poor conditions produced more leaves, spikes and longer leaves and in case of P. lanceolata, they had also higher photosynthetic capacity. The progeny of P. media mothers that had resprouted after disturbance was favored in nutrient poor conditions whereas the progeny of undisturbed plants was favored in nutrient rich conditions. This study demonstrates that maternal effects may play a role in the success of either a seeding or a resprouting strategy in environments with different nutrient availability. Moreover, we showed that alteration of photosynthetic capacity, even during adult stages, is a mechanism through which maternal plants may impact their progeny. [ABSTRACT FROM AUTHOR]

. Questions: What is the relative role of the bud bank, seed and various species traits in the regeneration of urban plant communities after severe disturbances? Do invasive and exotic species, highly abundant in disturbed communities, regenerate better than native species after disturbance? Methods: Hand tilling was applied to three urban plant communities with and without additional herbicide treatment to exclude regeneration from the bud bank. Plant traits were determined from the literature and databases. Species responses to the treatments were evaluated with RDA analyses in CANOCO. Linear models were applied to identify traits that could predict the responses of species to disturbance. Results: The bud bank played a key role in regeneration in the plots without herbicide. In the plots with herbicide treatment, the seed bank was important in re-establishing vegetation after disturbance. Exclusion of the bud bank by using herbicide allowed the establishment of small annuals, whereas biennials and perennials were successful in plots where the bud bank was not inhibited by herbicide. Exotic species with a long residence time in the local flora were successful in plots where regeneration from the bud bank was excluded, whereas species with short residence times or that were invasive were suppressed by both types of disturbance. Conclusion: In response to various types of disturbance, species with different regeneration strategies (either seeds or bud bank) were promoted. Exotic species were suppressed primarily by disturbance, which suggests that factors other than just regenerative capability contributed to the high abundance of exotics in urban communities. [ABSTRACT FROM AUTHOR]