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Plants employ various strategies to mitigate the impact of herbivory and one such strategy involves the associations with fungal endophytes. Some cool‐season forage grasses benefit from protection against herbivores by Epichloë fungal endophytes. However, since the maintenance of symbiosis relies on the plant, costs of hosting endophytes have been also observed. This becomes particularly crucial when forage varieties, inoculated with endophytes that are nontoxic to livestock but still protect host against insect herbivores, experience significant foliage loss (defoliation). We investigated the impact of a nontoxic Epichloë endophyte on the responses of tall fescue plants to defoliation across two morphotype varieties, Continental and Mediterranean, and different seasonal contexts. Under specific defoliation treatments, endophyte‐symbiotic plants showed reduced postdefoliation recovery, indicating the costs of hosting the endophyte for host plants. However, these conditions were not the most severe for plant growth. Regardless of the endophyte's presence, plants from Continental morphotype exhibited superior recovery than those from Mediterranean morphotype, an effect that was more pronounced in summer. Notably, the endophyte promoted plant growth after defoliation in winter for both morphotypes. Our study offers insights into mitigating endophyte‐associated costs on plant recovery postdefoliation by strategically managing cutting intensity and frequency, considering the seasonal variation. [ABSTRACT FROM AUTHOR]

Managing ecosystems to sequester soil carbon requires a thorough understanding of complex soil processes. Here, we integrate these soil processes through the metaphor of a game—one that moves through multiple dimensions (from macro‐aggregates to micropores and clay particles) and scales (from centimeters to nanometers) of the soil. The rules of the game are based on current understanding of soil carbon persistence, which differs from the classic humus concept of molecular complexity. The game's objective is to win points, by keeping "tokens" (plant‐derived organic compounds) within the soil organic matter for as long as possible. The game begins when tokens enter different "pool‐levels" (plant litter, particulate organic matter, dissolved organic matter, and mineral‐associated organic matter) of the soil, either directly or after metabolic transformation by soil biota. Points are lost through either respiration by soil biota or leaching. We invite readers to play this game and explore different natural ecosystems and land‐use scenarios to better comprehend complex soil processes. [ABSTRACT FROM AUTHOR]

Crucial to our understanding of plant ecology is the consideration of the eco‐physiological responses and constraints of plant–fungal symbioses throughout the native distribution range of their host.We examined key eco‐physiological roles of two co‐occurring fungal symbionts [Epichloë endophytes and arbuscular mycorrhizal fungi (AMF)] in the endemic grass Hordeum comosum across a wide bioclimatic gradient and contrasting grazing severity. We sampled H. comosum plants along four humid‐to‐arid transects in Patagonia, Argentina, covering its entire distribution range and determined Epichloë presence, AMF root colonization, nitrogen and phosphorus concentration, intrinsic water‐use efficiency (iWUE, the ratio of photosynthesis to stomatal conductance) and 18O‐enrichment of cellulose in shoots.Root colonization by AMF increased with Epichloë presence. All plants hosted Epichloë in the humid range of the gradient, but symbioses occurrence decreased towards arid sites which also displayed severe grazing symptoms at site level.Symbiosis with Epichloë correlated positively with shoot nitrogen concentration in the centre of the distribution range, and with shoot phosphorus concentration across the entire distribution range.The site‐level relationship of AMF colonization with 18O‐enrichment and iWUE suggested that mycorrhiza boosted stomatal conductance in humid environments but curbed it in arid environments.While the interpretation of interactions and potential causalities from observational studies should be done with caution, this study demonstrates distinct correlations between plant–fungal symbiont associations and key resource parameters (phosphorus, nitrogen and iWUE vs. 18O‐enrichment). Such correlations may suggest particular functional roles for these symbionts in the ecology of their host plant. A free Plain Language Summary can be found within the Supporting Information of this article. [ABSTRACT FROM AUTHOR]

This study aimed at investigating the effects of an autochthonous microbial inoculant microencapsulated by spray‐drying on fermentation parameters, microbiological composition, mycotoxin level and aerobic stability of maize and lucerne silages. Experiment 1, a completely randomized design with a 2 × 2 × 4 factorial arrangement of treatments, evaluated inoculation (control or Lactobacillus plantarum Hv75, Pediococcus acidilactici 3903 and Lactobacillus buchneri B463), packing density (148.5 kg dry matter (DM)/m3 or 181.5 kg DM/m3) and storage period (0, 1, 30 or 60 days) in maize silage. Lactic acid bacteria (LAB) supplementation produced higher DM and lower acetic acid and deoxynivalenol contents compared to the control (p < 0.05). However, these differences were small in terms of practical applications. Experiment 2 evaluated effects of microbial inoculation (similar as in experiment 1), wilting time (3 or 21 h) and storage period (0, 3, 30 or 60 days) in lucerne silage. LAB supplementation increased DM and lactic acid content, reduced pH and concentrations of acetic acid, ethanol and ammonia nitrogen/total nitrogen compared to the control (p < 0.05). In addition, inoculation increased total LAB population and decreased yeast and mould counts (p < 0.05). Although the strains displayed potential to be used as a bio‐inoculant at different lucerne moisture levels, prolonged wilting positively influenced DM, crude protein and fibre degradation (p < 0.05). Therefore, the addition of this spray‐dried inoculant to lucerne silages with longer wilting could be recommended for the attainment of silage quality. [ABSTRACT FROM AUTHOR]

BACKGROUND: The effect of plant size (seedlings versus young plants versus adult plants) on the phenotypic level of glyphosate resistance and selection intensity (SI) in Sorghum halepense with and without a reduced glyphosate translocation resistance mechanism was evaluated. RESULTS: Resistance parameters [the 50% lethal dose (LD50) and the dose required to cause a 50% reduction in plant growth (GR50)] in adult plants were notably higher than in seedlings regardless of the resistance status. However, under similar plant size increases, populations comprised of glyphosate‐resistant (R) individuals showed higher survival and growth when glyphosate treated compared with glyphosate‐susceptible (S) plants. An increase in SI was always evident with increasing glyphosate doses. However, the rate of increase in SI was higher under glyphosate selection of young R and S plants, followed by seedlings and adult R and S plants. However, in conditions of R seedlings coexisting with adult S plants under glyphosate treatment (1000–4000 g ha−1), selection against glyphosate resistance was observed. CONCLUSION: Any increase in size from the seedling stage of R plants translates into an amplification of resistance. Depending on the particular size combinations of spatially coexisting R and S plants, selection for glyphosate resistance may be faster, slower or even not evident. © 2018 Society of Chemical Industry Depending on the particular size combination of spatially coexisting glyphosate‐resistant (R) and susceptible (S) plants, the intensity of glyphosate selection may increase or decrease under increasing glyphosate doses. [ABSTRACT FROM AUTHOR]

Waterlogging imposes severe stress to the plant, and the interplay between root and aerial organs in the adjustment to this stress is poorly understood. A set of recombinant inbred lines ( RILs) of L otus japonicus ( Gifu B-129 × Miyakojima MG-20) was subjected to control and waterlogging conditions for 21 d, and 12 traits related to leaf physiological functioning, root aerenchyma formation, shoot and root morphology, and dry mass accumulation were assessed to generate phenomic networks. The phenomic network became more complex under waterlogging as a result of the incorporation of root aerenchyma and dark-adapted Fv/ Fm. Significant waterlogging-induced variation was found for stomatal conductance, dark-adapted Fv/ Fm and aerenchyma. The RILs with stronger induction of aerenchyma in response to waterlogging tended to show reduced negative impact of this stress on root growth but suffered average impact on shoot growth. The RILs that retained higher stomatal conductance under waterlogging tended to retain higher dark-adapted Fv/ Fm and shoot growth under waterlogging conditions but showed average impact on root traits. We propose a model where, although the stress experienced by the roots during waterlogging is transmitted to the shoot, shoots and roots deal with waterlogging in a less interdependent manner than often assumed. [ABSTRACT FROM AUTHOR]

Symbiosis between cool-season grasses and vertically transmitted fungal endophytes are common and significantly impact on ecosystem function. This makes the understanding of the underlying mechanisms to symbiotic individuals frequency in local populations much more interesting. Most studies have been focused on the differential fitness between symbiotic and non-symbiotic counterparts (relative fitness), barely considering other mechanisms. We performed a microcosms experiment to evaluate whether grazing alters the dynamics of the endophyte Neotyphodium occultans in the annual grass Lolium multiflorum by simultaneously modifying the relative fitness and the endophyte efficiency to be transmitted from host plants to seeds. Grazing was simulated by means of clipping and trampling on symbiotic and non-symbiotic plants growing separately, in soils obtained from paddocks, differing in their agronomic management history (natural grassland vs. ryegrass promotion). Seed production showed a complex pattern as it depended on the symbiotic status of the plants, the level of grazing and the agro-ecological context. Grazed plants produced three times fewer seeds than ungrazed plants only in microcosms with endophyte-symbiotic plants in soils from ryegrass promotion. Endophyte benefits on seed production were exclusively observed in ungrazed plants in the same soil. Symbiotic plants produced symbiotic and non-symbiotic seeds in all the treatments. While the production of non-symbiotic seeds by these plants was not affected by grazing and the soil, grazing reduced the production of symbiotic seeds in both contexts. Grazing negative effect on the density of fully infected spikes determined a significant increment in the transmission failures which were not modified by agro-ecological contexts. Therefore, grazing can modulate symbiosis dynamics through reducing seed production and endophyte transmission efficiency. Transmission has been disregarded, but it is a context-dependent process that could lead to a gradual reduction in the symbiotic plants frequency in a population if the mutualism effectiveness does not outweigh transmission failures. [ABSTRACT FROM AUTHOR]