Marjo Helander

Marjo Helander
University of Turku | UTU · Department of Biology

About

159
Publications
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Publications

Publications (159)
Article
Conventional agricultural practices favoring the use of glyphosate-based herbicides (GBHs) increase the risk of GBH residues ending up in animal feed, feces, and, eventually, manure. The use of poultry manure as organic fertilizer in the circular food economy increases the unintentional introduction of GBH residues into horticultural and agricultur...
Article
• Glyphosate is the most widely used non‐selective herbicide in the world. Glyphosate residues in soil can affect plant quality by modifying plant physiology, hormonal pathways, and traits, with potential consequences for plants’ interactions with herbivores. • We explored these indirect effects in the context of plant‐herbivore interactions in a p...
Article
Full-text available
Glyphosate is the world’s most widely used agrochemical. Its use in agriculture and gardening has been proclaimed safe because humans and other animals do not have the target enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). However, increasing numbers of studies have demonstrated risks to humans and animals because the shikimate metaboli...
Article
Full-text available
Purpose In cold climates, glyphosate residues may linger in soils, with effects on plant–microbe interactions and, consequently, plant performance. Here, we explore the influence of glyphosate residues on the endophytic microbiota (bacteria and fungi) and performance of the perennial nitrogen-fixing weed Lupinus polyphyllus. Methods In a common ga...
Article
Full-text available
Glyphosate is the most widely used herbicide with a yearly increase in global application. Recent studies report glyphosate residues from diverse habitats globally where the effect on non-target plants are still to be explored. Glyphosate disrupts the shikimate pathway which is the basis for several plant metabolites. The central role of phytohormo...
Article
Full-text available
Plants host taxonomically and functionally complex communities of microbes. However, ecological studies on plant-microbe interactions rarely address the role of multiple co-occurring plant-associated microbes. Here, we contend that plant-associated microbes interact with each other and can have joint consequences for higher trophic levels. In this...
Article
Glyphosate-based products (GBP) are the most common broad-spectrum herbicides worldwide. The target of glyphosate is the enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) in the shikimate pathway, which is virtually universal in plants. The inhibition of the enzyme stops the production of three essential amino acids: phenylalanine, tyrosin...
Article
Full-text available
Epichloë festucae is a common symbiont of the perennial and widely distributed cool season grass, Festuca rubra . The symbiosis is highly integrated involving systemic growth of the fungus throughout above-ground host parts and vertical transmission from plant to its offspring via host seeds. However, the nature of symbiosis is labile ranging from...
Article
Plant roots are abundantly colonized by dark septate endophytic (DSE) fungi in virtually all ecosystems. DSE fungi are functionally heterogeneous and their relationships with plants range from antagonistic to mutualistic. Here, we consider the role of by-product benefits in DSE and other root–fungal symbioses. We compared host investments against s...
Article
Full-text available
Glyphosate has become the best-selling herbicide used in agriculture, horticulture, silviculture, and urban environments. It disrupts the shikimate metabolic pathway and thereby blocks the production of aromatic amino acids, which are the basis for several plant metabolites. Glyphosate residues are reported in soils from diverse environments, but t...
Article
Full-text available
Glyphosate is the leading herbicide worldwide, but it also affects prokaryotes because it targets the central enzyme (5-enolpyruvylshikimate-3-phosphate, EPSP) of the shikimate pathway in the synthesis of the three essential aromatic amino acids in bacteria, fungi and plants. Our results reveal that bacteria may easily become resistant to glyphosat...
Article
Full-text available
Glyphosate is the most common broad-spectrum herbicide. It targets the key enzyme of the shikimate pathway, 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), which synthesizes three essential aromatic amino acids (phenylalanine, tyrosine and tryptophan) in plants. Because the shikimate pathway is also found in many prokaryotes and fungi, the wid...
Article
Many symbiotic microbes can aid their host plant's defense against herbivores and pathogens either directly or indirectly through plant-mediated mechanisms. Thus, microbes are of interest to agricultural research. In this study, we used vertically transmitted Epichloë species because these fungal endophytes of grasses produce alkaloids that have be...
Article
Full-text available
Glyphosate-based herbicides (GBHs) are the most frequently used herbicides globally. They were launched as a safe solution for weed control, but recently, an increasing number of studies have shown the existence of GBH residues and highlighted the associated risks they pose throughout ecosystems. Conventional agricultural practices often include th...
Article
Full-text available
Controversial glyphosate-based herbicides (GBHs) are the most frequently used herbicides globally. GBH residues in the wild, in animal and human food may expose non-target organisms to health risks, yet the developmental and cumulative effects of GBHs on physiology and reproduction remain poorly understood. We present the first long-term study on t...
Preprint
Full-text available
Glyphosate is the leading herbicide worldwide, but it also affects prokaryotes because it targets the central enzyme (EPSPS) of the shikimate pathway in the synthesis of the three essential aromatic amino acids in autotrophs. Our results reveal that bacteria easily become resistant to glyphosate through changes in the EPSPS active site. This indica...
Article
Full-text available
Variation in plant communities is likely to modulate the feeding and oviposition behavior of herbivorous insects, and plant‐associated microbes are largely ignored in this context. Here, we take into account that insects feeding on grasses commonly encounter systemic and vertically transmitted (via seeds) fungal Epichloë endophytes, which are regar...
Article
Glyphosate is the most used herbicide worldwide, targeting physiological pathways in plants. Recent studies have shown that glyphosate can also cause toxic effects in animals. We investigated the glyphosate-based herbicide (GBH)-induced changes in potato (Solanum tuberosum) plant chemistry and the effects of a GBH on the survival rate and oxidative...
Preprint
Full-text available
Glyphosate is the most common broad-spectrum herbicide. It targets the key enzyme of the shikimate pathway, 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), which synthesizes three essential aromatic amino acids (phenylalanine, tyrosine and tryptophan) in plants. Because the shikimate pathway is also found in many prokaryotes and fungi, the wid...
Article
Full-text available
Controversial glyphosate-based herbicides (GBHs) are the most frequently used herbicides globally. GBH residues are detected in soil, water, crops, and food products, potentially exposing non-target organisms to health risks; these organisms include wildlife, livestock, and humans. However, the potential for GBH-related parental effects are poorly...
Article
Here we examined whether glyphosate affects the microbiota of herbivores feeding on non-target plants. Colorado potato beetles (Leptinotarsa decemlineata) were reared on potato plants grown in pots containing soil treated with glyphosate-based herbicide (GBH) or untreated. Per the manufacturer's safety recommendations, the GBH soil treatments were...
Article
Full-text available
Microbes have driven eco-evolutionary adaptations organizing biodiversity from the origin of life. They are ubiquitous and abundant, facilitating the biochemical processes that make Earth habitable and shape ecosystem structures, functions, and services. Recent studies reveal that commensalistic and beneficial microbes associated with wild and dome...
Article
Full-text available
Glyphosate-based herbicides (GBH) are the most widely used pesticides globally. Their persistence in soils and effects on non-target organisms have become a concern in agricultural and natural ecosystems. We experimentally studied, whether residues of GBH (Roundup Gold) or pure glyphosate in soils affect the germination or sprouting and growth of c...
Preprint
Full-text available
Controversial glyphosate-based herbicides (GBHs) are the most frequently used herbicides across the globe. In an increasing number of studies, researchers have identified GBH residues in soil, water, crops, and food products exposing non-target organisms to health risks; these organisms include wildlife, livestock, and humans. However, GBH-related...
Article
Controversial glyphosate-based herbicides (GBHs) are the most frequently used herbicides globally. An increasing number of studies have identified GBH residues in soil, water and even human food that may expose non-target organism including wildlife, livestock, and humans to health risks. After a heated debate, European Union allowed the use of GBH...
Article
Full-text available
Many grasses (Poaceae) have symbiotic fungal endophytes, which affect livestock by producing unpalatable or harmful secondary compounds. Less is known about the repelling effects of fungal endophytes on avian grazers despite potential wildlife management implications. Herbivorous goose (Branta spp.) species may become a nuisance in recreational use...
Article
Full-text available
Background: Phenotypic variation within species challenges the identification of meaningful taxonomic units and the quantification of evolutionarily relevant biodiversity. Aims: We studied usefulness of the present taxonomic classification of species and subspecies within Festuca rubra complex. Methods: We categorised F. rubra s. l. plants collecte...
Article
Full-text available
Despite an increasing concern of consequences of using vast amounts of glyphosate-based herbicides in agroecosystems, their potential effects on non-target soil organisms and soil functioning are mostly unknown. It has also been argued that fields in northern latitudes should be under special surveillance as the short active period of decomposers m...
Poster
Full-text available
Glyphosate is the globally most used herbicide against a wide range of weeds. Glyphosate has been considered safe to animals as it mainly targets physiological pathways in plants. However, recent toxicological studies have shown that glyphosate can cause various toxic effects also on animals. Glyphosate can also affect directly the synthesis of pla...
Article
Background: Systemic Epichloë endophytes are common fungal symbionts of many cool-season grasses. They are known for their capability of increasing host plant tolerance against biotic and abiotic stressors, including grass pathogens. However, results on endophyte-mediated disease resistance have been ambiguous, and the underlying mechanisms of dise...
Article
Full-text available
Recent work on microbiomes is revealing the wealth and importance of plant-microbe interactions. Microbial symbionts are proposed to have profound effects on fitness of their host plants and vice versa, especially when their fitness is tightly linked. Here we studied local adaptation of host plants and possible fitness contribution of such symbiosi...
Data
Number of genotypes per population. Number of genotypes per population included in the reciprocal transplant experiment of Festuca rubra with and without Epichloë symbiont. (DOCX)
Data
Number of flowering culms in the field. Distribution of genotypic means for number of flowering culms for the host plant Festuca rubra from northern Finland, Faroe Islands, southern Finland and Spain in the first year in northern Finland, Faroe Islands and southern Finland and Spain in a four-way reciprocal transplant experiment in local environmen...
Data
Fitness data for the reciprocal transplant experiment. Data for Festuca rubra genotypes at the four transplantation sites used in the analysis including explanations for the data columns (XLSX)
Data
Descriptive statistics by region. Descriptive statistics (proportion/mean ± SD) and sample size (n; number of plants and number of genotypes in brackets) by region of origin for fitness estimates at each reciprocal transplant site. (DOCX)
Data
Descriptive statistics by Epichloë status. Descriptive statistics (proportion/mean ± SD) and sample size (n; number of plants and number of genotypes) by Epichloë status, region of origin for fitness estimates at each reciprocal transplant site. (DOCX)
Data
Phenotypic plasticity in biomass. Reaction norms for mean biomass for Festuca rubra genotypes across sites. (TIF)
Data
Significance of fitness differences between plants with and without Epichloë. Results of likelihood ratio tests between generalized linear models in R testing for effect of presence of Epichloë in flowering propensity and biomass in second year at each reciprocal transplant site of Festuca rubra in northern and southern Finland, Faroe Islands and S...
Data
Flowering propensity in the field. Mean flowering propensity of survivors in a four-way reciprocal transplant experiment of the host plant Festuca rubra from northern Finland, Faroe Islands, southern Finland and Spain in their local environments in three study years. (TIF)
Article
Full-text available
Keystone microbial species have driven eco-evolutionary processes since the origin of life. However, due to our inability to detect the majority of microbiota, members of diverse microbial communities of fungi, bacteria and viruses have largely been ignored as keystone species in past literature. Here we tested whether heritable Epichloë species of...
Article
Full-text available
We conducted a large‐scale population genetic survey of genetic diversity of the host grass Festuca rubra s.l., which fitness can be highly dependent on its symbiotic fungus Epichloë festucae, to evaluate genetic variation and population structure across the European range. The 27 studied populations have previously been found to differ in frequenc...
Article
Glyphosate is the globally most used herbicide against a wide range of weeds. Glyphosate has been considered safe to animals as it mainly targets physiological pathways in plants. However, recent toxicological studies have revealed that glyphosate can cause various toxic effects also on animals. In this study, we investigated the direct toxic effec...
Article
Full-text available
Our aim was to study the effects of glyphosate, tilling practice and cultivation history on mycorrhizal colonization and growth of target (weeds) and non-target (crops) plants. Glyphosate, the world's most widely used pesticide, inhibits an enzyme found in plants but also in microbes. We examined the effects of glyphosate treatment applied in the p...
Article
Full-text available
Microbial plant symbionts have been suggested to mediate plant-soil feedback and affect ecosystem functions. Systemic Epichloë fungal endophytes of grasses are found to mediate litter decomposition. These effects are often linked to alkaloids produced by Epichloë species, which are hypothesized to negatively affect decomposers. Although endophytes...
Article
Full-text available
‘Cry for help’ hypothesis predicts that attraction of predators with chemical or visual cues can decrease insect damage of plants. Visual cues involve changes in photosynthetic activity and the reflectance of leaves, and there is some evidence that birds may use these changes as foraging cues. However, changes in the visual properties of leaves hav...
Article
Full-text available
Polyploidy and symbiotic Epichloë fungal endophytes are common and heritable characteristics that can facilitate environmental range expansion in grasses. Here we examined geographic patterns of polyploidy and the frequency of fungal endophyte colonized plants in 29 Festuca rubra L. populations from eight geographic sites across latitudes from Spai...
Data
Endophyte status and cytometric data of the plants with the geographic information, grazing level and mean normalized difference vegetation index (mean NDVI) of the collection sites. (XLS)
Article
Full-text available
Background and aims Systemic Epichloë endophytes produce alkaloids that protect their grass hosts against pathogens and herbivores. These alkaloids, together with other endophyte induced changes in litter quality, may decelerate the decomposition of infected grass litter, but so far no study has tested whether the effects on decomposition rate tran...
Article
Full-text available
Human assisted plant invasions from Europe to North America have been more common than the reverse. We tested endophyte-mediated performance of tall fescue in parallel three year experiments in Europe and the USA using endophyte infected and uninfected wild and cultivated plants. Experimental plants were subjected to nutrient and water treatments....
Data
Seasonal changes in day length at the study sites. (PDF)
Data
Biomass and number of flowerheads of the experimental plants. (XLS)
Data
Growth and reproduction of tall fescue. Biomass (x±S.E.) and number of flowerheads (x±S.E.) of wild origin (A = island of Åland, G = Island of Gotland, S = coastal Sweden) and cultivar (Retu and KY-31) plants treated with water (W), nutrients (N) or their combination (WN). C = control with no water or nutrient applications. (PDF)
Data
The experimental field at the University of Kentucky experimental farm in Eden Shale, Kentucky, USA. (JPG)
Data
The experimental field at Turku Botanical Garden, University of Turku, Finland. (JPG)
Data
Monthly rainfall and mean temperature at the study sites in Kentucky and Finland. (PDF)
Article
Litter decomposition is a key ecosystem process which returns nutrients from dead plant material to mineral forms in the soil. We examined whether systemic fungal endophytes modulate recycling of nutrients directly by altering litter decomposition. We studied litter decomposition mediated by Epichloë endophytes in litter-bag experiments. We examine...
Article
Full-text available
Certain Pooideae species form persistent symbiosis with fungal endophytes of Epichloë genus. Although endophytes are known to impact the ecology and evolution of host species, their effects on parameters related with quality of plant biomass has been elusive. This article provides information about parameters related with the quality of plant litte...
Article
Full-text available
The closely linked fitness of the Epichloë symbiont and the host grass is presumed to align the coevolution of the species towards specialization and mutually beneficial cooperation. Ecological observations demonstrating that Epichloë-grass symbioses can modulate grassland ecosystems via both above- and belowground ecosystem processes support this....
Article
Full-text available
The closely linked fitness of the Epichloë symbiont and the host grass is presumed to align the coevolution of the species towards specialization and mutually beneficial cooperation. Ecological observations demonstrating that Epichloë-grass symbioses can modulate grassland ecosystems via both above- and belowground ecosystem processes support this....
Chapter
Full-text available
The Epichloë fungal endophytes that inhabit grasses have potentially large-scale consequences for macro- and micro-organisms and food chains in agriculture. Over 40 years of study on the benefits of symbiotic Epichloë fungal endophytes for host grasses, investigations have focused on the major agricultural species, tall fescue and perennial ryegras...
Article
There is an urgent need to create new solutions for sustainable agricultural practices that circumvent the heavy use of fertilizers and pesticides and increase the resilience of agricultural systems to environmental change. Beneficial microbial symbionts of plants are expected to play an important role in integrated pest management schemes over the...
Article
Full-text available
Many grass species are symbiotic with systemic, vertically-transmitted, asymptomatic Epichloë endophytic fungi. These fungi often produce alkaloids that defend the host against herbivores. We studied how environmental variables affect alkaloids in endophyte-infected tall fescue (Schedonorus phoenix) from three Northern European wild origins and the...