Soil microbial community responses to the fungal endophyte Neotyphodium in Italian ryegrass

Casas, Cecilia; Omacini, Marina; Montecchia, Marcela Susana; Correa, Olga Susana

doi:10.1007/s11104-010-0607-8

Cited by 58 publications

(30 citation statements)

References 41 publications

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“…To achieve contrasting proportions of endophyte‐symbiotic individuals in Lolium seeds, one year before the experiment, we collected seeds from an old‐field pampean grassland (Carlos Casares, Argentina 34°06′S, 60°25′W) dominated by Lolium with ≈ 95% endophytic individuals (Omacini et al ). For previous studies, we also selected this Lolium population to investigate how fungal endophytes may impact on host population and its interaction with multiple above and belowground ecosystem components (Omacini et al , , , Casas et al ). Half of them were treated with the fungicide triadimenol (0.5 g p.a.…”

Section: Methodsmentioning

confidence: 99%

Multi‐symbiotic systems: functional implications of the coexistence of grass–endophyte and legume–rhizobia symbioses

García-Parisi

Lattanzi

Grimoldi

et al. 2014

Oikos

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The coexistence of symbionts with different functional roles in co‐occurring plants is highly probable in terrestrial ecosystems. Analyses of how plants and microbes interact above‐ and belowground in multi‐symbiotic systems are key to understand community structure and ecosystem functioning. We performed an outdoor experiment in mesocosms to investigate the consequences of the interaction of a provider belowground symbiont of legumes (nitrogen‐fixing bacteria) and a protector aerial fungal symbiont of grasses (Epichloё endophyte) on nitrogen dynamics and aboveground net primary productivity. Four plants of Trifolium repens (Trifolium, a perennial legume) either inoculated or not with Rhizobium leguminosarum, grew surrounded by 16 plants of Lolium multiflorum (Lolium, an annual grass), with either low or high levels of the endophyte Neotyphodium occultans. After five months, we quantified the number of nodules in Trifolium roots, shoot biomass of both plant species, and the contribution of atmospheric nitrogen fixation vs. soil nitrogen uptake to above ground nitrogen in each plant species. The endophyte increased grass biomass production (+ 16%), and nitrogen uptake from the soil – the main source for the grass. Further, it reduced the nodulation of neighbour Trifolium plants (−50%). Notably, due to a compensatory increase in nitrogen fixation per nodule, this reduced neither its atmospheric nitrogen fixation – the main source of nitrogen for the legume – nor its biomass production, both of which were doubled by rhizobial inoculation. In consequence, the total amount of nitrogen in aboveground biomass and aboveground productivity were greatest in mesocosms with both symbionts (i.e. high rhizobia + high endophyte). These results show that, in spite of the deleterious effect of the endophyte on the establishment of the rhizobia–legume symbiosis, the coexistence of these symbionts, leading to additive effects on nitrogen capture and aboveground productivity, can generate complementarity on the functioning of multi‐symbiotic systems.

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Section: Methodsmentioning

confidence: 99%

Multi‐symbiotic systems: functional implications of the coexistence of grass–endophyte and legume–rhizobia symbioses

García-Parisi

Lattanzi

Grimoldi

et al. 2014

Oikos

Self Cite

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“…), whereas above‐ground endophytes may alter PSF through changing root exudation (Casas et al . ). It has been well‐established that plants can integrate physiological responses and biomass allocation to heterogeneity in soil, as well as heterogeneity in light availability (del Pino, Brandt & Burns ).…”

Section: Role Of Psf In the Fieldmentioning

confidence: 97%

“…Herbivory tends to promote positive feedback from the soil decomposer subsystem (Bardgett & Wardle 2003) and can overrule the negative feedback effects (Veen et al 2014). Effects of grazing may also change PSF effects by altering soil organic matter (Burke et al 1998), whereas above-ground endophytes may alter PSF through changing root exudation (Casas et al 2011). It has been well-established that plants can integrate physiological responses and biomass allocation to heterogeneity in soil, as well as heterogeneity in light availability (del Pino, Brandt & Burns 2015).…”

Section: Role Of Psf In the Fieldmentioning

confidence: 99%

Where, when and how plant–soil feedback matters in a changing world

et al. 2016

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Summary 1.It is increasingly acknowledged that plant-soil feedbacks may play an important role in driving the composition of plant communities and functioning of terrestrial ecosystems. However, the mechanistic understanding of plant-soil feedbacks, as well as their roles in natural ecosystems in proportion to other possible drivers, is still in its infancy. Such knowledge will enhance our capacity to determine the contribution of plant-soil feedback to community and ecosystem responses under global environmental change. 2. Here, we review how plant-soil feedbacks may develop under extreme drought and precipitation events, CO 2 and nitrogen enrichment, temperature increase, land use change and plant species loss vs. gain. We present a framework for opening the 'black box of soil' considering the responses of the various biotic components (enemies, symbionts and decomposers) of plant-soil feedback to the global environmental changes, and we discuss how to integrate these components to understand and predict the net effects of plant-soil feedbacks under the various scenarios of change. 3. To gain an understanding of how plant-soil feedback plays out in realistic settings, we also use the framework to discuss its interaction with other drivers of plant community composition, including competition, facilitation, herbivory, and soil physical and chemical properties. 4. We conclude that understanding the role that plant-soil feedback plays in shaping the responses of plant community composition and ecosystem processes to global environmental changes requires unravelling the individual contributions of enemies, symbionts and decomposers. These biotic factors may show different response rates and strengths, thereby resulting in different net magnitudes and directions of plant-soil feedbacks under various scenarios of global change. We also need tests of plant-soil feedback under more realistic conditions to determine its contribution to changes in patterns and processes in the field, both at ecologically and evolutionary relevant time-scales.

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“…The third mechanism would be via root exudation. Although Neotyphodium endophytes inhabit only in aerial plant tissues, effects on root-feeding herbivores and soil-dwelling organisms (Latch 1993;Bernard et al 1997) suggest that endophyte compounds might be exuded by the roots of infected plants affecting the soil microflora (Omacini et al 2004;Casas et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Evidence for leaf endophyte regulation of root symbionts: effect of Neotyphodium endophytes on the pre-infective state of mycorrhizal fungi

et al. 2011

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Neotyphodium endophytes and arbuscular mycorrhizal (AM) fungi are common constituents of natural grasslands. The plant-endophyte symbiosis can introduce changes in soil conditions that affect the density and activity of different functional groups of soil organisms. In the present work we performed in vitro assays to evaluate the effect of root and endophyte exudates on the pre-infective state of mycorrhizal fungi (Gigaspora margarita and G. rosea). Plant roots of Bromus setifolius from populations of Patagonia, and four strains of Neotyphodium were used to obtain the exudates. Root exudates of infected plants, at a high concentration, significantly increased AMF hyphal branches and length relative to exudates from naturally endophyte free plants. The effect of Neotyphodium endophyte exudates on AMF mycelial length varied depending on strain and the concentration used, suggesting a differential interaction between endophyte and AMF species. AMF hyphal branches were increased by Neotyphodium fungal exudates in both mycorrhizal species. A few previous studies have suggested that Neotyphodium endophytes can reduce mycorrhizal sporulation and colonization of host roots in commonlycultivated agronomic hosts. In this study we report the opposite effect in B. setifolius. This study reports the direct and positive effect of root exudates from plants in symbiosis with Neotyphodium, on AMF pre-infective state. Further, identical effects were detected using exudates from Neotyphodium endophytes.

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Soil microbial community responses to the fungal endophyte Neotyphodium in Italian ryegrass

Abstract: Cool-season grasses commonly harbor fungal endophytes in their aerial tissues. However

Cited by 58 publications

References 41 publications

Multi‐symbiotic systems: functional implications of the coexistence of grass–endophyte and legume–rhizobia symbioses

Multi‐symbiotic systems: functional implications of the coexistence of grass–endophyte and legume–rhizobia symbioses

Where, when and how plant–soil feedback matters in a changing world

Evidence for leaf endophyte regulation of root symbionts: effect of Neotyphodium endophytes on the pre-infective state of mycorrhizal fungi

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