scholarly journals Epichloë Endophyte-Promoted Seed Pathogen Increases Host Grass Resistance Against Insect Herbivory

2022 ◽  
Vol 12 ◽  
Author(s):  
Miika Laihonen ◽  
Kari Saikkonen ◽  
Marjo Helander ◽  
Beatriz R. Vázquez de Aldana ◽  
Iñigo Zabalgogeazcoa ◽  
...  
Keyword(s):  
Pathogenic Fungus ◽  
Insect Herbivory ◽  
Common Garden ◽  
Trophic Levels ◽  
Context Dependency ◽  
Research Station ◽  
Natural Setting ◽  
Plant Seed ◽  
Aphid Infestation ◽  
Red Fescue

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 study we recorded the occurrence of the plant seed pathogenic fungus Claviceps purpurea and aphids (Sitobion sp.) on an established field experiment with red fescue (Festuca rubra) plants symbiotic to a seed transmitted endophytic fungus Epichloë festucae (E+) or non-symbiotic (E–). Both fungi are known to produce animal-toxic alkaloids. The study was conducted in a semi-natural setting, where E+ and E– plants from different origins (Spain and Northern Finland) were planted in a randomized design in a fenced common garden at Kevo Subarctic Research Station in Northern Finland. The results reveal that 45% of E+ plants were infected with Claviceps compared to 31% of E– plants. Uninfected plants had 4.5 times more aphids than Claviceps infected plants. By contrast, aphid infestation was unaffected by Epichloë symbiosis. Claviceps alkaloid concentrations correlated with a decrease in aphid numbers, which indicates their insect deterring features. These results show that plant mutualistic fungi can increase the infection probability of a pathogenic fungus, which then becomes beneficial to the plant by controlling herbivorous insects. Our study highlights the complexity and context dependency of species–species and multi-trophic interactions, thus challenging the labeling of species as plant mutualists or pathogens.

scholarly journals Insect herbivory facilitates the establishment of an invasive plant pathogen

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Martin M. Gossner ◽  
Ludwig Beenken ◽  
Kirstin Arend ◽  
Dominik Begerow ◽  
Derek Peršoh
Keyword(s):  
Invasive Plant ◽  
Pathogenic Fungus ◽  
Feeding Activity ◽  
Insect Herbivory ◽  
Forest Health ◽  
Mechanical Damage ◽  
Pathogenic Fungi ◽  
Fungal Colonization ◽  
Feeding Damage ◽  
The Impact

AbstractPlants can be severely affected by insect herbivores and phytopathogenic fungi, but interactions between these plant antagonists are poorly understood. We analysed the impact of feeding damage by the abundant herbivore Orchestes fagi on infection rates of beech (Fagus sylvatica) leaves with Petrakia liobae, an invasive plant pathogenic fungus. The fungus was not detected in hibernating beetles, indicating that O. fagi does not serve as vector for P. liobae, at least not between growing seasons. Abundance of the fungus in beech leaves increased with feeding damage of the beetle and this relationship was stronger for sun-exposed than for shaded leaves. A laboratory experiment revealed sun-exposed leaves to have thicker cell walls and to be more resistant to pathogen infection than shaded leaves. Mechanical damage significantly increased frequency and size of necroses in the sun, but not in shade leaves. Our findings indicate that feeding damage of adult beetles provides entry ports for fungal colonization by removal of physical barriers and thus promotes infection success by pathogenic fungi. Feeding activity by larvae probably provides additional nutrient sources or eases access to substrates for the necrotrophic fungus. Our study exemplifies that invasive pathogens may benefit from herbivore activity, which may challenge forest health in light of climate change.

scholarly journals Context-dependency in biodiversity-multifunctionality relationships is driven by nitrogen availability and plant functional composition

2020 ◽  
Author(s):  
Noémie A. Pichon ◽  
Seraina L. Cappelli ◽  
Santiago Soliveres ◽  
Tosca Mannall ◽  
Thu Zar Nwe ◽  
...  
Keyword(s):  
Species Richness ◽  
Plant Species ◽  
Functional Diversity ◽  
Experimental Studies ◽  
Plant Species Richness ◽  
Trophic Levels ◽  
Context Dependency ◽  
Composition Gradient ◽  
Nitrogen Enrichment ◽  
Functional Composition

SummaryThe ability of an ecosystem to deliver multiple functions at high levels (multifunctionality) typically increases with biodiversity but there is substantial variation in the strength and direction of biodiversity effects, suggesting context-dependency. However, the drivers of this context dependency have not been identified and understood in comparative meta-analyses or experimental studies. To determine how different factors modulate the effect of diversity on multifunctionality, we conducted a large grassland experiment with 216 communities, crossing a manipulation of plant species richness (1-20 species) with manipulations of resource availability (nitrogen enrichment), plant functional composition (gradient in mean specific leaf area [SLA] to manipulate abundances of fast vs. slow species), plant functional diversity (variance in SLA) and enemy abundance (fungal pathogen removal). We measured ten functions, above and belowground, related to productivity, nutrient cycling and energy transfer between trophic levels, and calculated multifunctionality. Plant species richness and functional diversity both increased multifunctionality, but their effects were context dependent. Species richness increased multifunctionality, but only when communities were assembled with fast growing (high SLA) species. This was because slow species were more redundant in their functional effects, whereas fast species tended to promote different functions. Functional diversity also increased multifunctionality but this effect was dampened by nitrogen enrichment, however, unfertilised, functionally diverse communities still delivered more functions than low diversity, fertilised communities. Our study suggests that a shift towards exploitative communities will not only alter ecosystem functioning but also the strength of biodiversity-functioning relationships, which highlights the potentially complex effects of global change on multifunctionality.

scholarly journals A cascade of evolutionary change alters consumer-resource dynamics and ecosystem function

2012 ◽  
Vol 279 (1741) ◽  
pp. 3184-3192 ◽  
Author(s):  
Matthew R. Walsh ◽  
John P. DeLong ◽  
Torrance C. Hanley ◽  
David M. Post
Keyword(s):  
Life History ◽  
Ecosystem Function ◽  
Life History Evolution ◽  
Evolutionary Change ◽  
Ecological Impacts ◽  
Trophic Levels ◽  
Natural Setting ◽  
Resource Dynamics ◽  
History Evolution ◽  
Consumer Resource

It is becoming increasingly clear that intraspecific evolutionary divergence influences the properties of populations, communities and ecosystems. The different ecological impacts of phenotypes and genotypes may alter selection on many species and promote a cascade of ecological and evolutionary change throughout the food web. Theory predicts that evolutionary interactions across trophic levels may contribute to hypothesized feedbacks between ecology and evolution. However, the importance of ‘cascading evolutionary change’ in a natural setting is unknown. In lakes in Connecticut, USA, variation in migratory behaviour and feeding morphology of a fish predator, the alewife ( Alosa pseudoharengus ), drives life-history evolution in a species of zooplankton prey ( Daphnia ambigua ). Here we evaluated the reciprocal impacts of Daphnia evolution on ecological processes in laboratory mesocosms. We show that life-history evolution in Daphnia facilitates divergence in rates of population growth, which in turn significantly alters consumer-resource dynamics and ecosystem function. These experimental results parallel trends observed in lakes. Such results argue that a cascade of evolutionary change, which has occurred over contemporary timescales, alters community and ecosystem processes.

scholarly journals Biotic predictors complement models of bat and bird responses to climate and tree diversity in European forests

2019 ◽  
Vol 286 (1894) ◽  
pp. 20182193 ◽  
Author(s):  
Luc Barbaro ◽  
Eric Allan ◽  
Evy Ampoorter ◽  
Bastien Castagneyrol ◽  
Yohan Charbonnier ◽  
...  
Keyword(s):  
Functional Diversity ◽  
Environmental Changes ◽  
Insect Herbivory ◽  
Biotic Interactions ◽  
Trophic Levels ◽  
Explained Variance ◽  
Spider Abundance ◽  
Insect Activity ◽  
Bat Diversity ◽  
Functional Evenness

Bats and birds are key providers of ecosystem services in forests. How climate and habitat jointly shape their communities is well studied, but whether biotic predictors from other trophic levels may improve bird and bat diversity models is less known, especially across large bioclimatic gradients. Here, we achieved multi-taxa surveys in 209 mature forests replicated in six European countries from Spain to Finland, to investigate the importance of biotic predictors (i.e. the abundance or activity of defoliating insects, spiders, earthworms and wild ungulates) for bat and bird taxonomic and functional diversity. We found that nine out of 12 bird and bat diversity metrics were best explained when biotic factors were added to models including climate and habitat variables, with a mean gain in explained variance of 38% for birds and 15% for bats. Tree functional diversity was the most important habitat predictor for birds, while bats responded more to understorey structure. The best biotic predictors for birds were spider abundance and defoliating insect activity, while only bat functional evenness responded positively to insect herbivory. Accounting for potential biotic interactions between bats, birds and other taxa of lower trophic levels will help to understand how environmental changes along large biogeographical gradients affect higher-level predator diversity in forest ecosystems.

scholarly journals Ubiquity of Insect-Derived Nitrogen Transfer to Plants by Endophytic Insect-Pathogenic Fungi: an Additional Branch of the Soil Nitrogen Cycle

2013 ◽  
Vol 80 (5) ◽  
pp. 1553-1560 ◽  
Author(s):  
Scott W. Behie ◽  
Michael J. Bidochka
Keyword(s):  
Panicum Virgatum ◽  
Pathogenic Fungus ◽  
Insect Herbivory ◽  
Pathogenic Fungi ◽  
Nitrogen Transfer ◽  
Metarhizium Robertsii ◽  
Content Type ◽  
Lecanicillium Lecanii ◽  
Worldwide Distribution ◽  
Insect Pathogenic Fungi

ABSTRACTThe study of symbiotic nitrogen transfer in soil has largely focused on nitrogen-fixing bacteria. Vascular plants can lose a substantial amount of their nitrogen through insect herbivory. Previously, we showed that plants were able to reacquire nitrogen from insects through a partnership with the endophytic, insect-pathogenic fungusMetarhizium robertsii. That is, the endophytic capability and insect pathogenicity ofM. robertsiiare coupled so that the fungus acts as a conduit to provide insect-derived nitrogen to plant hosts. Here, we assess the ubiquity of this nitrogen transfer in fiveMetarhiziumspecies representing those with broad (M. robertsii,M. brunneum, andM. guizhouense) and narrower insect host ranges (M. acridumandM. flavoviride), as well as the insect-pathogenic fungiBeauveria bassianaandLecanicillium lecanii. Insects were injected with15N-labeled nitrogen, and we tracked the incorporation of15N into two dicots, haricot bean (Phaseolus vulgaris) and soybean (Glycine max), and two monocots, switchgrass (Panicum virgatum) and wheat (Triticum aestivum), in the presence of these fungi in soil microcosms. AllMetarhiziumspecies andB. bassianabut notL. lecaniishowed the capacity to transfer nitrogen to plants, although to various degrees. Endophytic association by these fungi increased overall plant productivity. We also showed that in the field, where microbial competition is potentially high,M. robertsiiwas able to transfer insect-derived nitrogen to plants.Metarhiziumspp. andB. bassianahave a worldwide distribution with high soil abundance and may play an important role in the ecological cycling of insect nitrogen back to plant communities.

scholarly journals Silicon and Plant Natural Defenses against Insect Pests: Impact on Plant Volatile Organic Compounds and Cascade Effects on Multitrophic Interactions

Plants ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 444 ◽  
Author(s):  
Leroy ◽  
Tombeur ◽  
Walgraffe ◽  
Cornélis ◽  
Verheggen
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Insect Pests ◽  
Insect Herbivory ◽  
Trophic Levels ◽  
Soil Parameters ◽  
Biotic Stresses ◽  
Plant Volatile ◽  
Volatile Organic ◽  
Cascade Effects

Environmental factors controlling silicon (Si) accumulation in terrestrial plant are key drivers to alleviate plant biotic stresses, including insect herbivory. While there is a general agreement on the ability of Si-enriched plant to better resist insect feeding, recent studies suggest that Si also primes biochemical defense pathways in various plant families. In this review, we first summarize how soil parameters and climate variables influence Si assimilation in plants. Then, we describe recent evidences on the ability of Si to modulate plant volatile emissions, with potential cascade effects on phytophagous insects and higher trophic levels. Even though the mechanisms still need to be elucidated, Si accumulation in plants leads to contrasting effects on the levels of the three major phytohormones, namely jasmonic acid, salicylic acid and ethylene, resulting in modified emissions of plant volatile organic compounds. Herbivore-induced plant volatiles would be particularly impacted by Si concentration in plant tissues, resulting in a cascade effect on the attraction of natural enemies of pests, known to locate their prey or hosts based on plant volatile cues. Since seven of the top 10 most important crops in the world are Si-accumulating Poaceae species, it is important to discuss the potential of Si mobility in soil-plant systems as a novel component of an integrated pest management.

scholarly journals Interaction between the Bird Cherry-Oat Aphid (Rhopalosiphum padi) and Stagonospora Nodorum Blotch (Parastagonospora nodorum) on Wheat

Insects ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 35
Author(s):  
Belachew Asalf ◽  
Andrea Ficke ◽  
Ingeborg Klingen
Keyword(s):  
Pathogenic Fungus ◽  
Rhopalosiphum Padi ◽  
Stagonospora Nodorum ◽  
Controlled Experiments ◽  
Aphid Infestation ◽  
Pests And Diseases ◽  
Septoria Nodorum Blotch ◽  
Wheat Leaves ◽  
Parastagonospora Nodorum ◽  
New Strategies

Wheat plants are under constant attack by multiple pests and diseases. Until now, there are no studies on the interaction between the aphid Rhopalosiphum padi and the plant pathogenic fungus Parastagonospora nodorum causal agent of septoria nodorum blotch (SNB) on wheat. Controlled experiments were conducted to determine: (i) The preference and reproduction of aphids on P. nodorum inoculated and non-inoculated wheat plants and (ii) the effect of prior aphid infestation of wheat plants on SNB development. The preference and reproduction of aphids was determined by releasing female aphids on P. nodorum inoculated (SNB+) and non-inoculated (SNB−) wheat leaves. The effect of prior aphid infestation of wheat plants on SNB development was determined by inoculating P. nodorum on aphid-infested (Aphid+) and aphid free (Aphid−) wheat plants. Higher numbers of aphids moved to and settled on the healthy (SNB−) leaves than inoculated (SNB+) leaves, and reproduction was significantly higher on SNB− leaves than on SNB+ leaves. Aphid infestation of wheat plants predisposed the plants to P. nodorum infection and colonization. These results are important to understand the interactions between multiple pests in wheat and hence how to develop new strategies in future integrated pest management (IPM).

scholarly journals Evaluation of Growth and Yield Characters of Garden Pea Genotypes at Dailekh, Mid-Western Nepal

2021 ◽  
Vol 15 ◽  
pp. 24-33
Author(s):  
Binod Prasad Luitel ◽  
Tul Bahadur Pun ◽  
Bishnu Bahadur Bhandari
Keyword(s):  
Powdery Mildew ◽  
Seed Yield ◽  
Block Design ◽  
Growth And Yield ◽  
Research Station ◽  
Garden Pea ◽  
Plant Seed ◽  
Resistant Genotype ◽  
Main Production ◽  
On Farm

Knowledge of phenotypic variation among the germplasm is important for the breeding program of garden pea. This study was conducted to evaluate the growth and yield traits of garden pea genotypes and to identify high yielding, and powdery mildew resistant genotype at Horticulture Research Station (HRS), Dailekh, Mid-western Nepal. Eleven garden pea genotypes were evaluated in the main production season (2018-2019) and compared with 'Sikkim Local' as standard variety, and the experiment was laid out in randomized complete block design with three replications. The analysis of variance revealed that genotypes had significant variation for all the traits studied except few insignificant traits. Significantly higher number of green pod/plant, green pod yield/plant, seed number/pod and seed yield/plant were recorded in genotypes DGP-12-18-2 and DGP-12-18-1 as compared with other studied genotypes. Genotype DGP-12-18-2, and DGP-12-18-1 exhibited resistant (2) to powdery mildew disease and these genotypes showed 45.8% and 16.6% yield advantage over the standard check 'Sikkim Local' variety. Therefore, genotypes DGP-12-18-2 and DGP-12-18-1 can be recommended to produce for fresh green pod and seed yield at on-farm condition of Mid-Western Nepal.

scholarly journals Characterizing the serotonin biosynthesis pathway upon aphid infestation in Setaria viridis leaves

2019 ◽  
Author(s):  
Anuma Dangol ◽  
Beery Yaakov ◽  
Georg Jander ◽  
Susan R Strickler ◽  
Vered Tzin
Keyword(s):  
Rhopalosiphum Padi ◽  
Foxtail Millet ◽  
Insect Herbivory ◽  
Ectopic Expression ◽  
Enrichment Analysis ◽  
Defense Responses ◽  
Pathway Enrichment Analysis ◽  
Setaria Viridis ◽  
Insect Feeding ◽  
Aphid Infestation

ABSTRACTSetaria viridis (green foxtail millet), a short life-cycle C4 plant in the Gramineae, serves as a resilient crop that provides good yield even in dry and marginal land. Although S. viridis has been studied extensively in the last decade, its defense responses, in particular the chemical defensive metabolites that protect it against insect herbivory, are unstudied. To characterize S. viridis defense responses, we conducted transcriptomic and metabolomic assays of plants infested with aphids and caterpillars. Pathway enrichment analysis indicated massive transcriptomic changes that involve genes from amino acid biosynthesis and degradation, secondary metabolites and phytohormone biosynthesis. The Trp-derived metabolite serotonin was notably induced by insect feeding. Through comparisons with known rice serotonin biosynthetic genes, we identified several predicted S. viridis Trp decarboxylases and cytochrome P450 genes that were up-regulated in response to insect feeding. The function of one Trp decarboxylase was validated by ectopic expression and detection of tryptamine accumulation in Nicotiana tabacum. To validate the defensive properties of serotonin, we used an artificial diet assay to show reduced Rhopalosiphum padi aphid survival with increasing serotonin concentrations. This demonstrated that serotonin is a defensive metabolite in S. viridis and is fundamental for understanding the adaptation of it to biotic stresses.HIGHLIGHTA combined transcriptomic and metabolomic profiling of Setaria viridis leaves response to aphid and caterpillar infestation identifies the genes related to the biosynthesis of serotonin and their function in defense.

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