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Strigolactone (SL), a plant hormone derived from carotenoids, has been recognized for its pivotal role in regulating plant growth. Nevertheless, the influence of SL on tall fescue (Festuca arundinacea) under low-light conditions remains unclear. This study aimed to investigate the impact of SL on various aspects of tall fescue, including its morphological characteristics, photosynthesis, levels of antioxidant and concentrations of SL, under low light intensity (LI). The findings showed that GR24, an artificial analog of SL, positively influenced several parameters of tall fescue under LI. In particular, it enhanced the morphological features such as plant height, leaf width, and biomass, while reducing the number of tillers. Furthermore, it improved the efficiency of photosynthetic by enhancing chlorophyll fluorescence and the gas exchange parameters, mitigating cell damage and improving the contents of antioxidants by increasing the levels of antioxidant enzymes and non-enzymatic antioxidant compounds. Moreover, treatment with SL led to elevated concentrations of this hormone and the levels of gene expression in related pathways. Owing to the immaturity of the genetic transformation system in tall fescue, partial validation through transgenic and mutant materials was obtained using Arabidopsis (Arabidopsis thaliana). These findings demonstrate that SL alleviates the physiological indicators of tall fescue under LI stress and enhances its tolerance to shade. Additionally, it suggests that SL may regulate the shade tolerance of tall fescue through the involvement of FaD14., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

Genome mining in association with the OSMAC (one strain, many compounds) approach provides a feasible strategy to extend the chemical diversity and novelty of natural products. In this study, we identified the biosynthetic gene cluster (BGC) of restricticin, a promising antifungal agent featuring a reactive primary amine, from the fungus Aspergillus sclerotiorum LZDX-33-4 by genome mining. Combining heterologous expression and the OSMAC strategy resulted in the production of a new hybrid product ( 1 ), along with N -acetyl-restricticin ( 2 ) and restricticinol ( 3 ). The structure of 1 was determined by spectroscopic data, including optical rotation and electronic circular dichroism (ECD) calculations, for configurational assignment. Compound 1 represents a fusion of restricticin and phytotoxic cichorin. The biosynthetic pathway of 1 was proposed, in which the condensation of a primary amine of restricticin with a precursor of cichorine was postulated. Compound 1 at 5 mM concentration inhibited the growth of the shoots and roots of Lolium perenne , Festuca arundinacea , and Lactuca sativa with inhibitory rates of 71.3 and 88.7% for L. perenne , 79.4 and 73.0% for F. arundinacea , and 58.2 and 52.9% for L. sativa. In addition, compound 1 at 25 μg/mL showed moderate antifungal activity against Fusarium fujikuroi and Trichoderma harzianum with inhibition rates of 22.6 and 31.6%, respectively. These results suggest that heterologous expression in conjunction with the OSMAC approach provides a promising strategy to extend the metabolite novelty due to the incorporation of endogenous metabolites from the host strain with exogenous compounds, leading to the production of more complex compounds and the acquisition of new physiological functions.

Background: Festuca kryloviana is a significant native grass species in the Qinghai Lake region, and its low emergence rate is a primary factor limiting the successful establishment of cultivated grasslands. The region's arid and low-rainfall climate characteristics result in reduced soil moisture content at the surface. Despite the recognized impact of water availability on plant growth, the specific role of moisture in seedling development remains not fully elucidated. This study aims to investigate the germination rate and seedling growth velocity of F. kryloviana seeds under varying moisture conditions, and to integrate physiological and transcriptomic analyses of seedlings under these conditions to reveal the mechanisms by which water influences seedling development., Results: The emergence rate of F. kryloviana seedlings exhibited an initial increase followed by a decrease with increasing moisture content. The highest emergence rate, reaching 75%, was observed under 20% soil moisture conditions. By the eighth day of the experiment, the lengths of the plumules and radicles under the optimal emergence rate (full water, FW) were 21.82% and 10.87% longer, respectively, than those under closely matching the soil moisture content during the background survey (stress water, SW). The differential development of seedlings under varying moisture regimes is attributed to sugar metabolism within the seeds and the accumulation of abscisic acid (ABA). At FW conditions, enhanced sugar metabolism, which generates more energy for seedling development, is facilitated by higher activities of α-amylase, sucrose synthase, and trehalose-6-phosphate synthase compared to SW conditions. This is reflected at the transcriptomic level with upregulated expression of the α-amylase (AMY2) gene and trehalose-6-phosphate synthase (TPS6), while genes associated with ABA signaling and transduction are downregulated. Additionally, under FW conditions, the expression of genes related to the chloroplast thylakoid photosystems, such as photosystem II (PSII) and photosystem I (PSI), is upregulated, enhancing the seedlings' light-capturing ability and photosynthetic efficiency, thereby improving their autotrophic capacity. Furthermore, FW treatment enhances the expression of the non-enzymatic antioxidant system, promoting metabolism within the seeds. In contrast, SW treatment increases the activity of the enzymatic antioxidant system, including peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT), to cope with water stress., Conclusions: Our experiment systematically evaluated the impact of moisture conditions on the growth and development of F. kryloviana seedlings. Physiological and transcriptomic data collectively indicate that adequate water (20%) supply enhances seedling growth and development by reducing ABA levels and increasing α-amylase activity within seeds, thereby boosting sugar metabolism and promoting the growth of seedling, which in turn leads to an improved emergence rate. Considering water management in future cultivation practices may be a crucial strategy for enhancing the successful establishment of F. kryloviana in grassland ecosystems., (© 2024. The Author(s).)

Background: Seed retention is the basic prerequisite for seed harvest. However, only little breeding progress has been achieved for this trait in the major forage grasses. The aim of this study was to evaluate the potential of plant genetic resources of the important fodder grasses Festuca pratensis Huds. and Lolium perenne L. as source for seed retention in the breeding process. Furthermore, the morphology of the abscission zone, where shattering occurs, was studied on the cell tissue level in different developmental stages of contrasting accessions., Results: 150 and 286 accessions of Festuca pratensis and Lolium perenne were screened for seed retention, respectively. Contrasting accessions were selected to be tested in a second year. We found a great variation in seed retention in Festuca pratensis and Lolium perenne, ranging from 13 to 71% (average: 35%) and 12 to 94% (average: 49%), respectively, in the first year. Seed retention was generally lower in the second year. Cultivars were within the accessions with highest seed retention in Festuca pratensis, but had lower seed retention than ecotypes in Lolium perenne. Field-shattered seeds had a lower thousand grain weight than retained seeds. Cell layers of the abscission zone appeared already in early seed stages and were nested within each other in accessions with high seed retention, while there were two to three superimposed layers in accessions with low seed retention., Conclusions: Plant genetic resources of Lolium perenne might be a valuable source for breeding varieties with high seed retention. However, simultaneous selection for high seed weight is necessary for developing successful commercial cultivars., (© 2024. The Author(s).)

The study investigated compounds present in the invasive grass Hordeum murinum L. subsp. murinum and tested the allelopathic potential of this plant against common meadow species Festuca rubra L. and Trifolium repens L. Gas chromatography-mass spectrometry (GC-MS) performed separately on the ears and stalks with leaves of wall barley revealed 32 compounds, including secondary metabolites, that may play an important role in allelopathy. Two compounds, N-butylbenzenesulfonamide (NBBS) and diphenylsulfone (DDS), were described for the first time for wall barley and the Poaceae family. The presence of 6,10,14-trimethylpentadecan-2-one (TMP) has also been documented. Aqueous extracts of H. murinum organs (ears and stalks with leaves) at concentrations of 2.5%, 5%, and 7.5% were used to evaluate its allelopathic potential. Compared to the control, all extracts inhibited germination and early growth stages of meadow species. The inhibitory effect was strongest at the highest concentration for both the underground and aboveground parts of the seedlings of the meadow species tested. Comparing the allelopathic effect, Trifolium repens proved to be more sensitive. In light of the results of the study, the removal of wall barley biomass appears to be important for the restoration of habitats where this species occurs due to its allelopathic potential.

Allopolyploidization entailing the merger of two distinct genomes in a single hybrid organism, is an important process in plant evolution and a valuable tool in breeding programs. Newly established hybrids often experience massive genomic perturbations, including karyotype reshuffling and gene expression modifications. These phenomena may be asymmetric with respect to the two progenitors, with one of the parental genomes being "dominant." Such "genome dominance" can manifest in several ways, including biased homoeolog gene expression and expression level dominance. Here we employed a k-mer-based approach to study gene expression in reciprocal Festuca pratensis Huds. × Lolium multiflorum Lam. allopolyploid grasses. Our study revealed significantly more genes where expression mimicked that of the Lolium parent compared with the Festuca parent. This genome dominance was heritable to successive generation and its direction was only slightly modified by environmental conditions and plant age. Our results suggest that Lolium genome dominance was at least partially caused by its more efficient trans-acting gene expression regulatory factors. Unraveling the mechanisms responsible for propagation of parent-specific traits in hybrid crops contributes to our understanding of allopolyploid genome evolution and opens a way to targeted breeding strategies., (© 2021 The Authors. The Plant Journal published by Society for Experimental Biology and John Wiley & Sons Ltd.)

Ryegrasses (Lolium spp.) and fescues (Festuca spp.) are closely related and widely cultivated perennial forage grasses. As such, resilience in the face of abiotic stresses is an important component of their traits. We have compared patterns of differentially expressed genes (DEGs) in roots and leaves of two perennial ryegrass genotypes and a single genotype of each of a festulolium (predominantly Italian ryegrass) and meadow fescue with the onset of water stress, focussing on overall patterns of DEGs and gene ontology terms (GOs) shared by all four genotypes. Plants were established in a growing medium of vermiculite watered with nutrient solution. Leaf and root material were sampled at 35% (saturation) and, as the medium dried, at 15%, 5% and 1% estimated water contents (EWCs) and RNA extracted. Differential gene expression was evaluated comparing the EWC sampling points from RNAseq data using a combination of analysis methods. For all genotypes, the greatest numbers of DEGs were identified in the 35/1 and 5/1 comparisons in both leaves and roots. In total, 566 leaf and 643 root DEGs were common to all 4 genotypes, though a third of these leaf DEGs were not regulated in the same up/down direction in all 4 genotypes. For roots, the equivalent figure was 1% of the DEGs. GO terms shared by all four genotypes were often enriched by both up- and down-regulated DEGs in the leaf, whereas generally, only by either up- or down-regulated DEGs in the root. Overall, up-regulated leaf DEGs tended to be more genotype-specific than down-regulated leaf DEGs or root DEGs and were also associated with fewer GOs. On average, only 5-15% of the DEGs enriching common GO terms were shared by all 4 genotypes, suggesting considerable variation in DEGs between related genotypes in enacting similar biological processes., Competing Interests: The authors have declared that no competing interests exist.

Soil legacies play an important role for the creation of priority effects. However, we still poorly understand to what extent the metabolome found in the soil solution of a plant community is conditioned by its species composition and whether soil chemical legacies affect subsequent species during assembly. To test these hypotheses, we collected soil solutions from forb or grass communities and evaluated how the metabolome of these soil solutions affected the growth, biomass allocation and functional traits of a forb (Dianthus deltoides) and a grass species (Festuca rubra). Results showed that the metabolomes found in the soil solutions of forb and grass communities differed in composition and chemical diversity. While soil chemical legacies did not have any effect on F. rubra, root foraging by D. deltoides decreased when plants received the soil solution from a grass or a forb community. Structural equation modelling showed that reduced soil exploration by D. deltoides arose via either a root growth-dependent pathway (forb metabolome) or a root trait-dependent pathway (grass metabolome). Reduced root foraging was not connected to a decrease in total N uptake. Our findings reveal that soil chemical legacies can create belowground priority effects by affecting root foraging in later arriving plants., (© 2021 The Authors. Plant, Cell & Environment published by John Wiley & Sons Ltd.)

High temperature damage impairs the growth of tall fescue by inhibiting secondary metabolites. Little is known about the regulation pattern of the fatty acids and carbohydrate metabolism at the whole-transcriptome level in tall fescue under high temperature stress. Here, two tall fescue genotypes, heat tolerant PI578718 and heat sensitive PI234881 were subjected to high temperature stress for 36 h. PI 578718 showed higher SPAD chloroplast value, lower EL and leaf injury than PI 234881 during the first 36 h high-temperature stress. Furthermore, by transcriptomic analysis, 121 genes were found to be induced during the second energy production phase in tall fescue exposed to high-temperature conditions, indicating that there may be one energy-sensing system in cool-season turfgrass to adapt high-temperature conditions. PI 578718 showed higher differentially expressed unigenes involved in fatty acids and carbohydrate metabolism compared with PI 234881 for 36 h heat stress. Interestingly, a metabolomic analysis using GC-MS uncovered that the sugars and sugar alcohol accounted for more than 65.06% of the total 41 metabolites content and high-temperature elevated the rate to 82.89-91.16% in PI 578718. High-temperature damage decreased the rate of fatty acid in the total 41 metabolites content and PI 578718 showed lower content than in PI 234881, which might be attributed to the down-regulated genes in fatty acid biosynthesis pathway in tall fescue. The integration of deep transcriptome and metabolome analyses provides systems-wide datasets to facilitate the identification of crucial regulation factors in cool-season turfgrass in response to high-temperature damage., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Tall fescue (Festuca arundinacea Schreb.) is a major cool-season forage and turfgrass species. The low tiller density and size dramatically limits its turf performance and forage yield. MicroRNAs (miRNA)-genes modules play critical roles in tiller development in plants. In this study, a genome-wide small RNA profiling was carried out in two tall fescue genotypes contrasting for tillering production ('Ch-3', high tiller production rate and 'Ch-5', low tiller production rate) and two types of tissue samples at different tillering development stage (Pre-tillering, grass before tillering; Tillering, grass after tillering). 'Ch-3', 'Ch-5', Pre-tillering, and Tillering samples were analyzed using high-throughput RNA sequencing., Results: A total of 222 million high-quality clean reads were generated and 208 miRNAs were discovered, including 148 known miRNAs belonging to 70 families and 60 novel ones. Furthermore, 18 miRNAs were involved in tall fescue tiller development process. Among them, 14 miRNAs displayed increased abundance in both Ch-3 and Tillering plants compared with that in Ch-5 and Pre-tillering plants and were positive with tillering, while another four miRNAs were negative with tiller development. Out of the three miRNAs osa-miR156a, zma-miR528a-3p and osa-miR444b.2, the rest of 15 miRNAs were newfound and associated with tiller development in plants. Based on our previous full-length transcriptome analysis in tall fescue, 28,927 potential target genes were discovered for all identified miRNAs. Most of the 212 target genes of the 18 miRNAs were dominantly enriched into "ubiquitin-mediated proteolysis", "phagosome", "fatty acid biosynthesis", "oxidative phosphorylation", and "biosynthesis of unsaturated fatty acids" KEGG pathways. In addition, bdi-miR167e-3p targets two kinase proteins EIF2AK4 and IRAK4, and osa-miR397a targets auxin response factor 5, which may be the significant miRNA-genes controllers in tillering development., Conclusions: This is the first genome-wide miRNA profiles analysis to identify regulators involved in tiller development in cool-season turfgrass. Tillering related 18 miRNAs and their 212 target genes provide novel information for the understanding of the molecular mechanisms of miRNA-genes mediated tiller development in cool-season turfgrass.

Intensive grazing increases the profitability and sustainability of small-scale dairy systems by reducing feeding costs. Kikuyu grass is a subtropical species from East Africa that has similar performance compared with temperate grasses when grazed by dairy cows in these systems during the summer rainy season but reduces growth and quality at low temperatures, when temperate species may have an advantage. The objective was to evaluate intensive grazing of kikuyu pastures (KYKY) alone or in association with two varieties of endophyte-free tall fescue, TF-33 (TF33) and Cajun II (CAJN), during the summer-autumn transition period when low temperatures set in, by lactating cows in small-scale dairy farms. Pasture variables were analysed with a split-plot design for sward height, net herbage accumulation and chemical composition, in vitro digestibility of organic matter, and estimated metabolisable energy content of herbage and concentrate. Experimental design for animal variables was a 3 × 3 Latin Square repeated three times with nine Holstein cows and 14 days experimental periods. Cows received 4.65 kg DM/day of a 16% CP commercial concentrate. Milk yield and composition, live weight, and body condition score were recorded. There were no significant differences (P > 0.05) for sward height and net herbage accumulation, nor for important components of chemical composition of herbages. There were no significant differences (P > 0.05) for milk yield (19 kg/cow/day) and composition, although differences (P < 0.05) were detected for live weight and body condition score. The conclusion is that there is no advantage of associating tall fescue with kikuyu in summer-autumn transition period for small-scale dairy systems.

In plants, tolerance to cadmium (Cd) stress is closely related to indole-3-acetic acid (IAA) and hydrogen peroxide (H 2 O 2 ). However, it is unclear whether Cd-resistant and -sensitive varieties respond differently to Cd stress. In this study, the effects of dimethylthiourea (DMTU, a H 2 O 2 scavenger) and p-chlorophenoxy isobutyric acid (PCIB, an IAA signaling inhibitor) on root growth, endogenous hormones and antioxidant system were investigated to decipher how DMTU and PCIB treatments alleviate the inhibition of root elongation in Cd-resistant (Commander) and -sensitive (Crossfire III) tall fescue varieties under Cd stress. Both varieties subjected to 10 μM Cd treatments for 12 h presented a substantial decrease in root elongation coupled with a reduction in brassinosteroid (BR) and zeatin riboside (ZR) contents, but the changes in IAA and abscisic acid (ABA) contents under Cd stress were opposite in the two varieties. In addition, the H 2 O 2 content and antioxidant enzyme activities significantly increased in both varieties. However, pretreatment with PCIB or DMTU mitigated the inhibition of root elongation caused by Cd, accompanied by the significant changes of aforementioned physiological parameters. PCIB significantly reduced the IAA content in 'Commander', while DMTU significantly increased the IAA content in 'Crossfire III' and effectively relieved the inhibition of root elongation. But both treatments decreased the Cd-induced H 2 O 2 accumulation. These results indicated that DMTU or PCIB can alleviate the Cd-inhibited root elongation in two varieties whose resistance differed under Cd stress, but they presented differences in the response of hormones, especially IAA, which may be due to the different adaptation mechanisms of two varieties in response to Cd stress., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Ecological theory produces opposing predictions about whether differences in the timing of life-history transitions, or "phenology," promote or limit coexistence. Phenological separation is predicted to create temporal niche differences, increasing coexistence, yet phenological separation could also competitively favor one species, increasing fitness differences and hindering coexistence. We experimentally manipulated relative germination timing, a critical phenological event, of two annual grass species, Vulpia microstachys and V. octoflora , to test these contrasting predictions. We parameterized a competition model to estimate within-season niche differences, fitness differences, and coexistence and to estimate coexistence when year-to-year fluctuations of germination timing occur. Increasing germination separation caused parallel changes in niche and fitness differences, with the net effect of weakening within-year coexistence. Both species experienced a competitive advantage by germinating earlier, and a 4-day head start allowed the generally inferior competitor to exclude the otherwise superior competitor. The overall consequence of germination separation was to limit coexistence within a given year, although year-to-year variation in the relative timing of germination was sufficient to support long-term coexistence. Our results clarify how phenological differences structure competitive interactions and highlight the need to quantify year-to-year variation in these differences to better understand species coexistence.

Grass endophytes have been shown to confer enhanced environmental resilience to symbiont cultivars with reports of modified growth. If inoculating with an endophyte (E+) made an accession morphologically distinct from its registered endophyte free (E-) accession, there could be protection and ownership issues for testing authorities and breeders. This study investigated if, in official Plant Breeders Rights (PBR) field trials, the morphological characteristics of E+and E- accessions of perennial ryegrass and tall fescue cultivars were sufficiently modified to designate them as mutually distinct and also distinct from their definitive accessions (Def), held by the testing authorities. Testing perennial ryegrass on 17 characters at 2 sites generated 48,960 observations and for tall fescue on 9 characters at 1 site, 12,960 observations (each for 3 accessions of 4 cultivars × 60 plants × 2 growing cycles). Distinctness required a p < 0.01 difference in a single character from the combined over years analysis (COYD). A few significant differences were recorded between E- and E+accessions. Cultivar Carn E+ was smaller than Carn E- for Infloresence Length (p < 0.01) in both years but COYD analysis (p < 0.05) was insufficient to declare distinctiveness. Overall, the number of observed differences between E-/E+ accessions was less or similar to the number expected purely by chance. In contrast, comparisons between Def and E- or E+ accessions showed a number of significant differences that were substantially more numerous than expected by chance. These results showed no conclusive evidence of endophyte inclusion creating false PBR distinctions but unexpectedly, several E- and E+ accessions were distinguished from their official definitive stock.

Due to the presence of toxic pollutants, soils in former military areas need remedial actions with environmentally friendly methods. Greenhouse experiments were conducted to investigate the aided phytostabilization of multi-heavy metals (HMs), i.e. Cd, Cr, Cu, Ni, Pb, Zn, in post-military soil by Festuca rubra and three mineral amendments (diatomite, dolomite and halloysite). The amendments were applied at 0 and 3.0% to each pot filled with 5 kg of polluted soil. After seven weeks of the phytostabilization, selected soil properties, biomass yield of F. rubra and immobilization of HMs by their accumulation in plant and redistribution among individual fractions in soil were determined. In addition, ecotoxicology parameters of non-amended and amended soil were established using Phytotoxkit (Sinapsis alba) and Ostracodtoxkit (Heterocypris incongruens) tests. The addition of halloysite significantly increased F. rubra biomass. Diatomite significantly increased both the Cd, Cu, Pb and Cr concentrations in the roots and the pH of the soil. The application of halloysite significantly decreased the Cd and Zn contents of the soil after the completion of the experiment. Dolomite and halloysite were more effective in HM immobilization in soil by decreasing their content in an exchangeable fraction than diatomite. These soil amendments significantly differentiated the length of S. alba roots and had a positive effect on the development of H. incongruens., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Lead is one of the most hazardous pollutants to both the environment as well as human beings. As one of the approaches to enhance phytoremediation, brassinosteroids are predicted as a potential candidate phytohormone for assisted phytoremediation. Few studies have focused on the physiological regulations of tall fescue plants (Festuca arundinacea Schreb.), a potential phytoremediation species, for its responses to applications of brassinosteroids under lead stress. Therefore, the objectives of this study were to investigate the effects of foliar application of 24-epibrassinolide, a brassinosteroids analogue, on reactive oxygen species accumulation and antioxidative defense systems of tall fescue when exposed to lead, and ultimately its potential to be used in phytoremediation. When exposed to lead (1000 mg/kg) for 80 d, decreases in shoot and root biomass of tall fescue biomass as well as chlorophyll and carotenoid productions were found. Foliar application of 24-epibrassinolide at three rates and five applications every 7 d improved the biomass of both shoots and roots, and increased the photosynthetic pigments. The improved lead tolerance in tall fescue plants after 24-epibrassinolide applications was associated with reduced H 2 O 2 and O 2 .- accumulations and increased antioxidative enzyme activities including superoxide dismutase, catalase, and guaiacol peroxidase. Additionally, osmoprotectants increased and lipid peroxidation decreased. Ultimately, foliar applications of 24-epibrassinolide enhanced the lead recovery rate of tall fescue plants, proving its potential role in phytoremediation for soil contaminated with heavy metals such as lead., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Inoculation of hybrid bermudagrass with plant growth-promoting rhizobacteria (PGPR) can increase plant growth and influence relationships with above-ground herbivores like fall armyworms. However, few experiments have evaluated PGPR applications relative to root herbivory. Root-feeding white grubs cause severe damage to grasses, especially in tall fescue pastures, golf courses, and lawns. Since bacterial inoculants enhance root growth, the goal of this study was to determine if the inoculation of hybrid bermudagrass by rhizobacteria can increase the tolerance of tall fescue and hybrid bermudagrass to damage from white grub feeding, and if PGPR are compatible with neonicotinoid insecticides commonly used for white grub control., Results: In trials with tall fescue and hybrid bermudagrass, grasses were treated with the PGPR strain mixture Blend 20 or nitrogen or left non-treated and were then infested with Japanese beetle grubs. Grasses treated with PGPR and nitrogen fertilizer produced significantly more top growth than the non-treated grub-infested controls. Tall fescue and hybrid bermudagrass treated with Blend 20 produced root mass similar to or greater than nitrogen fertilized grasses. Both grasses treated with Blend 20 had greater root mass than non-treated infested grass. No treatment negatively impacted grub survival, and weight gains of grubs were similar for all treatments. Bacterial strains were typically compatible with insecticides used to control white grubs., Conclusion: PGPR and nitrogen fertilization stimulate root growth resulting in tolerance of tall fescue and hybrid bermudagrass to white grub infestation. PGPR, acting as biostimulants to increase root biomass on grasses, may have utility for IPM of root herbivores. © 2019 Society of Chemical Industry., (© 2019 Society of Chemical Industry.)

Pot experiments were conducted under abiotic conditions to investigate the interactive influence of decabromodiphenyl ether (BDE-209) and lead (Pb) on the seed germination, germ length, root exudation and physiological characteristics of tall fescue (Festuca arundinaceae), and the uptake, accumulation of Pb and BDE-209 in the plant tissues. Results show that seed germination and germ length were impacted by Pb but less influenced by BDE-209. BDE-209 spiking (10 and 50 mg/L) could alleviate the toxicity of high Pb concentration on seed germination and growth. The chlorophyll content was significantly increased at 500 mg/kg Pb but declined at 2000 mg/kg Pb. Low-level Pb contamination (500 mg/kg) activated antioxidase activity; however, 2000 mg/kg Pb significantly reduced the antioxidase activity. Plant biomass slightly decreased at 500 mg/kg Pb but significantly declined at 2000 mg/kg Pb. The addition of a moderate dosage of BDE-209 (10-50 mg/kg) lessened Pb phytotoxicity, leading to improved plant growth relative to the case of Pb spiking alone. The exudate secretion was significantly enhanced by Pb addition, but BDE-209 spiking only caused slightly increased secretion. Pb could interfere with BDE-209 adsorption and translocation of tall fescue by affecting physiological behavior of the plant, but BDE-209 exhibited little influence on the Pb fate in the plant. Overall, BDE-209 had slight interference on the impact of Pb towards tall fescue. The results demonstrate the complex interactive effects of organic pollutants and heavy metals in the soil-plant system., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Tiller production in grass species is controlled by both axillary bud initiation and bud outgrowth, which may be regulated by plant hormones. However, how gibberellic acid (GA) affects tillering in perennial grass species is still unclear. This study aims to elucidate the roles and the underlying mechanisms of GA in regulating tiller development. Tall fescue seedlings were treated with different concentrations of GA3 by foliar application, dose-dependent inhibitory effects of GA on tiller production were observed. GA3 (25 μM) slowed down the transition from axillary buds to tillers by specifically inhibiting the outgrowth of axillary buds. GA-inhibition of tillering were not related to endogenous content for auxin or strigolactone, but was mainly due to the antagonistic interaction with cytokinins (CK), as shown by the decreased CK content and up-regulation expression of CK degradation genes in GA3-treated plants. Furthermore, GA could act through regulating the expression of FaTB1 specifically expressed in axillary buds to repress bud outgrowth. These results provide insights for the regulatory mechanisms of GA for tiller bud outgrowth through crosstalks with CK and signaling of FaTB1 expression., (Copyright © 2019 The Authors. Published by Elsevier B.V. All rights reserved.)

Tall fescue ( Festuca arundinacea ), an accumulator that is able to accumulate and excrete cadmium (Cd), has attracted much attention for its possible use in phytoremediation of heavy metal contaminated soils. In the present study, the interaction between Cd and Zn, and their uptake, translocation and accumulation under external Cd and Zn treatment in tall fescue were investigated. The concentrations of K, Ca, Mg in xylem sap under Cd and Zn treatment were measured to determine the level of mineral nutrients and their relationship with Cd alleviation. The result showed that Cd and Zn antagonized each other in the roots, while Cd antagonized Zn and Zn synergized Cd in the shoots of tall fescue. Compared with Cd only treatment, the concentrations of Ca, Mg and K in xylem sap increased after the addition of Zn, and they increased the most in the guttation. This result indicated that the addition of Zn facilitates the level of mineral elements to alleviate Cd toxicity, which might be used to improve the phytoremediation efficiency of Cd contaminated soils by tall fescue.

This study investigated effects of seed aging and imbibition on sugar metabolite concentrations in Epichloë endophyte-infected and endophyte-free seed of tall fescue ( Festuca arundinacea Schreb.). Two treatments, namely, accelerated aging and imbibition, were applied to the seeds, with embryo and endosperm tissues analyzed separately. Gas chromatography with flame ionization detection was employed for analysis of sugar metabolites within the seed tissues. Mannitol, ribitol, and trehalose were more abundant in embryo than endosperm tissues and were identified at consistently higher concentrations within endophyte-infected compared to endophyte-free seeds. The ratio of raffinose to sucrose significantly increased with seed aging in both endophyte-free and endophyte-infected embryo tissues, while significantly lower concentrations of trehalose were detected in tissues dissected from aged-seed regardless of endophyte status. This research provides fundamental insight into the metabolic details of endophyte survival in seed and provides a first evaluation of key carbohydrates present in the fungal-plant symbiosis.

Drought resistance is a crucial attribute of plants and to properly decipher its mechanisms, a valuable plant model is required. Lolium multiflorum is a forage grass characterized by a low level of abiotic stress resistance, whereas Festuca arundinacea is recognized as a species with drought resistance, including both stress avoidance and tolerance strategies. These two species can be crossed with each other. Two closely related L. multiflorum/F. arundinacea introgression forms with distinct levels of field drought resistance were involved, thus enabling the dissection of this complex trait into its crucial components. The processes occurring in roots were shown to be the most significant for the expression of drought resistance. Thus, the analysis was focused on the root architecture and the accumulation of selected hormones, primary metabolites and glycerolipids in roots. The introgression form, with a higher resistance to field water deficit was characterized by a deeper soil penetration by its roots, and it had a higher accumulation level of primary metabolites, including well recognized osmoprotectants, such as proline, sucrose or maltose, and an increase in phosphatidylcholine to phosphatidylethanolamine ratio compared to the low resistant form. A comprehensive model of root performance under water deficit conditions is presented here for the first time for the grass species of the Lolium-Festuca complex., (Copyright © 2019 Elsevier B.V. All rights reserved.)

In order to evaluate the resistance of lawn plant to Co 2+ at germination stage and discuss its concentration property at adult stage, four kinds of lawn plant which have some growth advantages in Co 2+ polluted environment were selected as experimental materials in this research. They are tall fescue, timothy grass, inflorescences, and annual ryegrass. The results show that the evaluation of resistance to Co 2+ of tall fescue's seed is the highest; the evaluation of resistance to Co 2+ of annual ryegrass seed is the lowest. The low consistence Co 2+ could improve the seed germination. With Co 2+ concentration increase, the accumulation coefficient of four plants increased at first and decreased later; the accumulation coefficient of underground portion is higher than the accumulation coefficient of aboveground; with Co 2+ concentration increase, the transfer coefficient of four plants have a remarkable decline. In these plants, the accumulation coefficient of tall fescue and annual ryegrass is bigger than other two plants. As the concentration of Co 2+ treatment increased to 100 mg/kg, the aboveground enrichment of Co 2+ in F. elata reached 75 mg/kg, followed by L. multiflorum (68.9 mg/kg), P. pratense (48.8 mg/kg), and D. glomerata (27.2 mg/kg).The highest underground enrichment of Co 2+ in F. elata reached 836.46 mg/kg, in contrast to the lowest underground enrichment in D. glomerata, 264.67 mg/kg. It shows that fescue and annual ryegrass have a better enrichment property to Co 2+ and have a better prospect for the treatment of cobalt-contaminated soil. This research could provide some scientific basis and main technical approach for the soil contaminated by Co 2+ .

Objectives: The objective of this study was to establish transcriptome assemblies of Festulolium hybrids under salt stress, and identify genes regulated across the hybrids in response to salt stress. The development of transcriptome assemblies for Festulolium hybrids and cataloguing of genes regulated under salt stress will facilitate further downstream studies., Results: Plants were grown at three salt concentrations (0.5%, 1% and 1.5%) and phenotypic and transcriptomic data was collected. Salt stress was confirmed by progressive loss of green leaves as salt concentration increased from 0 to 1.5%. We generated de-novo transcriptome assemblies for two Festulolium pabulare festucoid genotypes, for a single Festulolium braunii genotype, and a single F. pabulare loloid genotype. We also identified 1555 transcripts that were up regulated and 1264 transcripts that were down regulated in response to salt stress in the Festulolium hybrids. Some of the identified transcripts showed significant sequence similarity with genes known to be regulated during salt and other abiotic stresses.

The facilitation mechanism maintains ecosystem richness by increasing seedling recruitment. Overgrazed grasslands of northwestern Patagonia are invaded by shrubs that could promote the seedling recruitment of forage species. We investigated the role of Acaena splendens shrubs on the maintenance of diversity and its usefulness as a nurse shrub in the recruitment of Festuca pallescens, a grass of high forage value present with a low cover in degraded grasslands. To test the performance of A.splendens as a nurse plant in non-degraded grassland, we recorded the species richness four years inside of A. splendens senescent shrubs and in gaps among dominant tussock grasses. Species were grouped in four functional groups: annual and biannual herbs and grasses, perennial herbs, perennial grasses and shrubs. To test the usefulness of A. splendens in the restoration of degraded grassland, we monitored the seedling emergence and survival of F. pallescens inside A. splendens and in gaps. We related seedling survival to meteorological and microenvironmental conditions. Species richness was higher in Acaena nurse plants than in gaps. The frequency of functional groups, with exception of annual and biannual herbs and grasses, were higher in Acaena than in gaps. Seedling emergence and survival of F. pallescens were higher in Acaena, but the seedlings died in summer in both microsites. Mean maximum temperature was higher and mean minimum humidity lower in gaps than in Acaena during spring. However, the spring-summer season in which we monitored F. pallescens survival, was exceptionally dry and hot, affecting the survival of F. pallescens seedlings. Our results show that A. splendens act as a nurse species increasing the richness in the non-degraded grassland and facilitating the seedling recruitment of an important forage species in the degraded grassland. Nevertheless, the facilitation mechanism will fail in drought conditions, indicating that this restoration tool is limited by climate., Competing Interests: The authors have declared that no competing interests exist.

Epichloë species are fungal symbionts (endophytes) of cool-season grasses that transmit vertically via inflorescence primordia (IP), ovaries (OV), and ultimately, embryos. Epichloë coenophiala, an endophyte of tall fescue (Schedonorus arundinaceus), provides multiple protective benefits to the grass. We conducted transcriptome analysis of the tall fescue-E. coenophiala symbiosis, comparing IP, OV, vegetative pseudostems (PS), and the lemma and palea (LP) (bracts) of the young floret. Transcriptomes of host OV and PS exhibited almost no significant differences attributable to endophyte presence or absence. Comparison of endophyte gene expression in different plant parts revealed numerous differentially expressed genes (DEGs). The 150 endophyte DEGs significantly higher in PS over OV included genes for alkaloid biosynthesis and sugar or amino acid transport. The 277 endophyte DEGs significantly higher in OV over PS included genes for protein chaperones (including most heat-shock proteins), trehalose synthesis complex, a bax inhibitor-1 protein homolog, the CLC chloride ion channel, catalase, and superoxide dismutase. Similar trends were apparent in the Brachypodium sylvaticum-Epichloë sylvatica symbiosis. Gene expression profiles in tall fescue IP and LP indicated that the endophyte transcriptome shift began early in host floral development. We discuss possible roles of the endophyte DEGs in colonization of reproductive grass tissues.

Soil acidification can alter the biogeochemistry of ecosystems and adversely affect biota; however, there are still many debates about the toxicity of aluminum (Al) fractions and Al species in soil:water extracts to plants. In this study, five crude soils with different pH values (4.92-8.51) were collected, seeded with tall fescue and grown in rhizosphere boxes for 120 days. Then, soil properties, labile Al fractions and Al species in soil:water extracts were determined, and their toxicities to plants were analyzed. Our study showed that a stable exchangeable Al fraction (ExAl) pool exists and is supplied by other labile Al fractions. Dissolution of Al from adsorbed hydroxyl-Al fraction (HyAl) and organic-Al fraction (OrAl) may play important roles in soil Al toxicity, as HyAl and OrAl account for major parts of soil labile Al. Additionally, Al 3+ and mononuclear hydroxyl-Al species in soil:water extracts have few effects to plants. Nevertheless, high negative correlations were found between Al-F - complexes and tall fescue biomass, indicating their toxicity in the natural soil environment. Thus, in many cases, Al 3+ toxicity should not be emphasized because of its lower activity in soil water extracts. Moreover, toxicities of AlF 3 (aq) and AlF 4 - to plants should be emphasized, because they have been confirmed in soil water extracts in this study., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Alien chromosome introgression is used for the transfer of beneficial traits in plant breeding. For temperate forage grasses, much of the work in this context has focused on species within the ryegrasses (Lolium spp.) and the closely related fescues (Festuca spp.) particularly with a view to combining high forage quality with reliability and enhanced environmental services. We have analysed a L. perenne (perennial ryegrass) population containing the majority of a F. pratensis (meadow fescue) genome as introgressed chromosome segments to identify a) marker-trait associations for nutrient use and abiotic stress response across the family, and b) to assess the effects of introgression of F. pratensis genomic regions on phenotype. Using container-based assays and a system of flowing solution culture, we looked at phenotype responses, including root growth, to nitrogen and phosphorus status in the growing medium and abiotic stresses within this festulolium family. A number of significant marker/trait associations were identified across the family for root biomass on chromosomes 2, 3 and 5 and for heading date on chromosome 2. Of particular interest was a region on chromosome 2 associated with increased root biomass in phosphorus-limited conditions derived from one of the L. perenne parents. A genotype containing F. pratensis chromosome 4 as a monosomic introgression showed increased tiller number, shoot and root growth and genotypes with F. pratensis chromosome segment introgressions at different ends of chromosome 4 exhibited differential phenotypes across a variety of test conditions. There was also a general negative correlation between the extent of the F. pratensis genome that had been introgressed and root-related trait performances. We conclude that 1) the identification of alleles affecting root growth has potential application in forage grass breeding and, 2) F. pratensis introgressions can enhance quantitative traits, however, introgression can also have more general negative effects., Competing Interests: The authors have declared that no competing interests exist.

Background and Aims: Grassland-based livestock systems in cool maritime regions are commonly dominated by grass monocultures receiving relatively high levels of fertilizer. The current study investigated whether grass-legume mixtures can improve the productivity, resource efficiency and robustness of yield persistence of cultivated grassland under extreme growing conditions over a period of 5 years., Methods: Monocultures and mixtures of two grasses (Phleum pratense and Festuca pratensis) and two legumes (Trifolium pratense and Trifolium repens), one of which was fast establishing and the other temporally persistent, were sown in a field trial. Relative abundance of the four species in the mixtures was systematically varied at sowing. The plots were maintained under three N levels (20, 70 and 220 kg N ha-1 year-1) and harvested twice a year for five consecutive years. Yields of individual species and interactions between all species present were modelled to estimate the species diversity effects., Key Results: Significant positive diversity effects in all individual years and averaged across the 5 years were observed. Across years, the four-species equi-proportional mixture was 71 % (N20: 20 kg N ha-1 year-1) and 51 % (N70: 70 kg N ha-1 year-1) more productive than the average of monocultures, and the highest yielding mixture was 36 % (N20) and 39 % (N70) more productive than the highest yielding monoculture. Importantly, diversity effects were also evident at low relative abundances of either species group, grasses or legumes in the mixture. Mixtures suppressed weeds significantly better than monocultures consistently during the course of the experiment at all N levels., Conclusions: The results show that even in the less productive agricultural systems in the cool maritime regions grass-legume mixtures can contribute substantially and persistently to a more sustainable agriculture. Positive grass-legume interactions suggest that symbiotic N2 fixation is maintained even under these marginal conditions, provided that adapted species and cultivars are used.

Polycyclic aromatic hydrocarbon (PAH)-contaminated sites have a mixture of PAH of varying concentration which may affect PAH dissipation differently to contamination with a single PAH. In this study, pot experiments investigated the impact of PAH contamination on Medicago sativa, Lolium perenne, and Festuca arundinacea biomass and PAH dissipation from soils spiked with phenanthrene (Phe), fluoranthene (Flu), and benzo[a]pyrene (B[a]P) in single and mixed treatments. Stimulatory or inhibitory effects of PAH contamination on plant biomass yields were not different for the single and mixed PAH treatments. Results showed significant effect of PAH treatments on plant growth with an increased root biomass yield for F. arundinacea in the Phe (175%) and Flu (86%) treatments and a root biomass decrease in the mixed treatment (4%). The mean residual PAHs in the planted treatments and unplanted control for the single treatments were not significantly different. B[a]P dissipation was enhanced for single and mixed treatments (71-72%) with F. arundinacea compared to the unplanted control (24-50%). On the other hand, B[a]P dissipation was inhibited with L. perenne (6%) in the single treatment and M. sativa (11%) and L. perenne (29%) in the mixed treatment. Abiotic processes had greater contribution to PAH dissipation compared to rhizodegradation in both treatments. In most cases, a stimulatory effect of PAH contamination on plant biomass yield without an enhancement of PAH dissipation was observed. Plant species among other factors affect the relative contribution of PAH dissipation mechanisms during phytoremediation. These factors determine the effectiveness and suitability of phytoremediation as a remedial strategy for PAH-contaminated sites. Further studies on impact of PAH contamination, plant selection, and rhizosphere activities on soil microbial community structure and remediation outcome are required.

Strigolactones (SL) have recently been found to play roles in regulating root development. However, it remains unclear how SL may mediate root elongation of perennial grass species under different temperatures that differentially affect root growth. The objectives of this study were to examine effects of SL on root elongation of tall fescue and to examine the interactive effects of SL and auxin in regulating root growth under both non-stress and heat stress conditions. Tall fescue (cv. 'Kentuck-31') plants were treated with GR24 (a synthetic strigolactones), NAA (α-naphthylacetic acid), or NPA (auxin transport inhibitor N-1-naphthylphalamic acid) or their combination under non-stress control and heat stress (35/30 °C) in growth chamber. Crown root elongation was evaluated by measuring root length. Cell number and length in root tips were measured under confocal microscope. Expression levels of genes related to cell growth, SL signaling and auxin transport were determined. SL promoted crown root elongation in tall fescue under normal temperature and heat stress, and alleviated heat-inhibition of root growth. GR24-enhanced root elongation was accompanied with the increase in cell numbers, up-regulation of cell cycle-related genes, and down-regulation auxin transport-related genes in crown root tips of tall fescue. The positive effects of SL for promoting crown root elongation in tall fescue under both non-stress and heat stress could be mainly due to its regulation of cell division and involve the interference of auxin transport., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background: Tall fescue is a widely used cool season turfgrass and relatively sensitive to high temperature. Chemical compounds like melatonin (MT) and 24-epibrassinolide (EBL) have been reported to improve plant heat stress tolerance effectively., Results: In this study, we reported that MT and EBL pretreated tall fescue seedlings showed decreased reactive oxygen species (ROS), electrolyte leakage (EL) and malondialdehide (MDA), but increased chlorophyll (Chl), total protein and antioxidant enzyme activities under heat stress condition, resulting in improved plant growth. Transcriptomic profiling analysis showed that 4311 and 8395 unigenes were significantly changed after 2 h and 12 h of heat treatments, respectively. Among them, genes involved in heat stress responses, DNA, RNA and protein degradation, redox, energy metabolisms, and hormone metabolism pathways were highly induced after heat stress. Genes including FaHSFA3, FaAWPM and FaCYTC2 were significantly upregulated by both MT and EBL treatments, indicating that these genes might function as the putative target genes of MT and EBL., Conclusions: These findings indicated that heat stress caused extensively transcriptomic reprogramming of tall fescue and exogenous application of MT and EBL effectively improved thermotolerance in tall fescue.

Background: Grasslands are one of the most representative vegetation types accounting for about 20% of the global land area and thus the response of grasslands to climate change plays a pivotal role in terrestrial carbon balance. However, many current climate change models, based on earlier results of the doubling-CO 2 experiments, may overestimate the CO 2 fertilization effect, and as a result underestimate the potentially effects of future climate change on global grasslands when the atmospheric CO 2 concentration goes beyond the optimal level. Here, we examined the optimal atmospheric CO 2 concentration effect on CO 2 fertilization and further on the growth of three perennial grasses in growth chambers with the CO 2 concentration at 400, 600, 800, 1000, and 1200 ppm, respectively., Results: All three perennial grasses featured an apparent optimal CO 2 concentration for growth. Initial increases in atmospheric CO 2 concentration substantially enhanced the plant biomass of the three perennial grasses through the CO 2 fertilization effect, but this CO 2 fertilization effect was dramatically compromised with further rising atmospheric CO 2 concentration beyond the optimum. The optimal CO 2 concentration for the growth of tall fescue was lower than those of perennial ryegrass and Kentucky bluegrass, and thus the CO 2 fertilization effect on tall fescue disappeared earlier than the other two species. By contrast, the weaker CO 2 fertilization effect on the growth of perennial ryegrass and Kentucky bluegrass was sustained for a longer period due to their higher optimal CO 2 concentrations than tall fescue. The limiting effects of excessively high CO 2 concentrations may not only associate with changes in the biochemical and photochemical processes of photosynthesis, but also attribute to the declines in stomatal conductance and nitrogen availability., Conclusions: In this study, we found apparent differences in the optimal CO 2 concentrations for the growth of three grasses. These results suggest that the growth of different types of grasses may respond differently to future elevated CO 2 concentrations through the CO 2 fertilization effect, and thus potentially alter the community composition and structure of grasslands. Meanwhile, our results may also be helpful for improving current process-based ecological models to more accurately predict the structure and function of grassland ecosystems under future rising atmospheric CO 2 concentration and climate change scenarios.

Herbicide drift may have unintended impacts on native vegetation, adversely affecting individual species and plant communities. To determine the potential ecological effects of herbicide drift, small plant community plots were constructed using 9 perennial species found in different Willamette Valley (OR, USA) grassland habitats. Studies were conducted at 2 Oregon State University (Corvallis, OR, USA) farms in 2 separate years, with single and combined treatments of 0.01 to 0.2× field application rates (f.a.r.) of 1119 g ha -1 for glyphosate (active ingredient [a.i.] of 830 g ha -1 acid glyphosate) and 560 g ha -1 a.i. for dicamba. Plant responses were percentage of cover, number of reproductive structures, mature and immature seed production, and vegetative biomass. Herbicide effects differed with species, year, and, to a lesser extent, farm. Generally, 0.1 to 0.2× f.a.r. of the herbicides were required to affect reproduction in Camassia leichtlinii, Elymus glaucus, Eriophyllum lanatum, Festuca idahoensis, Iris tenax, and Prunella vulgaris. Eriophyllum lanatum also had a significant increase in percentage of immature seed dry weight with 0.01× f.a.r. of dicamba or the combination of glyphosate plus dicamba. Other species showed similar trends, but fewer significant responses. These studies indicated potential effects of low levels of herbicides on reproduction of native plants, and demonstrated a protocol whereby species growing in a constructed plant community can be evaluated for ecological responses. Environ Toxicol Chem 2017;36:2799-2813. Published 2017 SETAC. This article is a US government work and, as such, is in the public domain in the United States of America., (Published 2017 SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.)

A feature of cell wall arabinoxylan in grasses is the presence of ferulic acid which upon oxidative coupling by the action of peroxidases forms diferuloyl bridges between formerly separated arabinoxylans. Ferulate cross-linking is suspected of playing various roles in different plant processes. Here we investigate the role of cell wall feruloyaltion in two major processes, that of leaf growth and the turnover of cell wall arabinoxylans on leaf senescence in tall fescue using plants in which the level of cell wall ferulates has been reduced by targeted expression of the Aspergillus niger ferulic acid esterase A (FAEA) to the apoplast or Golgi. Analysis of FAE expressing plants showed that all the lines had shorter and narrower leaves compared to control, which may be a consequence of the overall growth rate being lower and occurring earlier in FAE expressing leaves than in controls. Furthermore, the final length of epidermal cells was shorter than controls, indicating that their expansion was curtailed earlier than in control leaves. This may be due to the observations that the deposition of both ether and ester linked monomeric hydroxycinnamic acids and ferulate dimerization stopped earlier in FAE expressing leaves but at a lower level than controls, and hydroxycinnamic acid deposition started to slow down when peroxidase levels increased. It would appear therefore that one of the possible mechanisms for controlling overall leaf morphology such as leaf length and width in grasses, where leaf morphology is highly variable between species, may be the timing of hydroxycinnamic acid deposition in the expanding cell walls as they emerge from cell division into the elongation zone, controlled partially by the onset of peroxidase activity in this region.

Contamination of soil by copper (Cu) has become a serious problem throughout the world, causing the reduction of agricultural yield and harmful effects on human health by entering the food chain. A glasshouse pot experiment was designed to evaluate the potential use of halloysite as an immobilizing agent in the aided phytostabilization of Cu-contaminated soil, using Festuca rubra L. The content of Cu in plants, i.e., total and extracted by 0.01 M CaCl₂, was determined using the method of spectrophotometry. Cu content in the tested parts of F. rubra differed significantly when halloysite was applied to the soil, as well as with increasing concentrations of Cu. The addition of halloysite significantly increased plant biomass. Cu accumulated in the roots, thereby reducing its toxicity to the aerial parts of the plant. The obtained values of bioconcentration and translocation factors observed for halloysite treatment indicate the effectiveness of using F. rubra in phytostabilization techniques., Competing Interests: The authors declare no conflict of interest.

Atmospheric CO 2 concentrations are predicted to double within the next century. Despite this trend, the extent and mechanisms through which elevated CO 2 affects grass-endophyte symbionts remain uncertain. In the present study, the growth, chemical composition and pathogen resistance of endophyte-infected (E+) and uninfected (E-) tall fescue were compared under elevated CO 2 conditions. The results showed that the effect of endophyte infection on the growth of tall fescue was significantly affected by elevated CO 2 . Significant advantage of E+ over E- tall fescue in tiller number, maximum net photosynthetic rate and shoot biomass occurred only under ambient CO 2 . With CO 2 concentration elevated, the beneficial effect of endophyte infection on the growth disappeared. Similarly, endophyte infection reduced lesion number and spore concentration of Curvularia lunata only under ambient CO 2 . These results suggest that the beneficial effect of endophyte infection on the growth and pathogen resistance of tall fescue could be counteracted by elevated CO 2. An explanation for the counteraction may be found in a change in photosynthesis and nutritive quality of leaf tissue.

Roughstalk bluegrass (Poa trivialis) is a weed in cool season grass seed production fields in Oregon. Populations of this weed are often greater in fields prone to waterlogging. A greenhouse study was conducted to investigate the morphological and physiological differences between recently established roughstalk bluegrass and tall fescue (Lolium arundinaceum) plants in response to simulated waterlogging. Differences in root morphological development and root respiration were found between waterlogged tall fescue and roughstalk bluegrass. Plants after 4 weeks of waterlogging, leaf number, plant height, and root biomass were reduced more in tall fescue than in roughstalk bluegrass plants. The root length increased 6% in waterlogged tall fescue plants, and decreased 42% in waterlogged roughstalk bluegrass plants, which lead to a shallower root system in roughstalk bluegrass. Root aerenchyma area increased more in waterlogged roughstalk bluegrass than in tall fescue. Alcohol dehydrogenase and lactate dehydrogenase activities increased in the roots of both species, but not in the leaves. The increases were greater in tall fescue than in roughstalk bluegrass. Turf quality, aboveground biomass, photosynthetic capacity, and water-soluble carbohydrate concentrations were reduced by waterlogging, but there were no differences over time or species. Thus, the shallower root system, larger aerenchyma, and reduced fermentation rates were the characteristics most likely to contribute to better waterlogging tolerance in roughstalk bluegrass compared to tall fescue and invasion of roughstalk bluegrass in waterlogged cool season grass seed fields.

The Festuca genus is thought to be the most numerous genus of the Poaceae family. One of the most agronomically important forage grasses, Festuca pratensis Huds. is treated as a model plant to study the molecular mechanisms associated with tolerance to winter stresses, including frost. However, the precise mapping of the genes governing stress tolerance in this species is difficult as its karyotype remains unrecognized. Only two F. pratensis chromosomes with 35S and 5S rDNA sequences can be easily identified, but its remaining chromosomes have not been distinguished to date. Here, two libraries derived from F. pratensis nuclear DNA with various contents of repetitive DNA sequences were used as sources of molecular probes for fluorescent in situ hybridisation (FISH), a BAC library and a library representing sequences most frequently present in the F. pratensis genome. Using FISH, six groups of DNA sequences were revealed in chromosomes on the basis of their signal position, including dispersed-like sequences, chromosome painting-like sequences, centromeric-like sequences, knob-like sequences, a group without hybridization signals, and single locus-like sequences. The last group was exploited to develop cytogenetic maps of diploid and tetraploid F. pratensis, which are presented here for the first time and provide a remarkable progress in karyotype characterization.

Climate change impacts rainfall patterns which may lead to drought stress in rain-fed agricultural systems. Crops with higher drought tolerance are required on marginal land with low precipitation or on soils with low water retention used for biomass production. It is essential to obtain plant breeding tools, which can identify genotypes with improved drought tolerance and water use efficiency (WUE). In C 3 plant species, the variation in discrimination against 13 C (Δ 13 C) during photosynthesis has been shown to be a potential indicator for WUE, where discrimination against 13 C and WUE were negatively correlated. The aim of this study was to determine the variation in the discrimination against 13 C between species and cultivars of three perennial C 3 grasses (Dactylis glomerata (cocksfoot), Festuca arundinacea (tall fescue) and Phalaris arundinacea (reed canary grass)) and test the relationships between discrimination against 13 C, season-long water use WUE B , shoot and root biomass production in plants grown under well-watered and water-limited conditions. The grasses were grown in the greenhouse and exposed to two irrigation regimes, which corresponded to 25% and 60% water holding capacity, respectively. We found negative relationships between discrimination against 13 C and WUE B and between discrimination against 13 C and shoot biomass production, under both the well-watered and water-limited growth conditions (p < 0.001). Discrimination against 13 C decreased in response to water limitation (p < 0.001). We found interspecific differences in the discrimination against 13 C, WUE B , and shoot biomass production, where the cocksfoot cultivars showed lowest and the reed canary grass cultivars highest values of discrimination against 13 C. Cocksfoot cultivars also showed highest WUE B , shoot biomass production and potential tolerance to water limitation. We conclude that discrimination against 13 C appears to be a useful indicator, when selecting C 3 grass crops for biomass production under drought conditions., (Copyright © 2017 Elsevier Masson SAS. All rights reserved.)

Heat stress transcription factors (HSFs) compose a large gene family, and different members play differential roles in regulating plant responses to abiotic stress. The objectives of this study were to identify and characterize an A2-type HSF, FaHsfA2c, in a cool-season perennial grass tall fescue (Festuca arundinacea Schreb.) for its association with heat tolerance and to determine the underlying physiological functions and regulatory mechanisms of FaHsfA2c imparting plant tolerance to heat stress. FaHsfA2c was localized in nucleus and exhibited a rapid transcriptional increase in leaves and roots during early phase of heat stress. Ectopic expression of FaHsfA2c improved basal and acquired thermotolerance in wild-type Arabidopsis and also restored heat-sensitive deficiency of hsfa2 mutant. Overexpression of FaHsfA2c in tall fescue enhanced plant tolerance to heat by triggering transcriptional regulation of heat-protective gene expression, improving photosynthetic capacity and maintaining plant growth under heat stress. Our results indicated that FaHsfA2c acted as a positive regulator conferring thermotolerance improvement in Arabidopsis and tall fescue, and it could be potentially used as a candidate gene for genetic modification and molecular breeding to develop heat-tolerant cool-season grass species., (© 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.)

Premise of the Study: Current ecological theory can provide insight into the causes and impacts of plant domestication. However, just how domestication has impacted intraspecific genetic variability (ITV) is unknown. We used 50 ecotypes and 35 cultivars from five grassland species to explore how selection drives functional trait coordination and genetic differentiation., Methods: We quantified the extent of genetic diversity among different sets of functional traits and determined how much genetic diversity has been generated within populations of natural ecotypes and selected cultivars., Key Results: In general, the cultivars were larger (e.g., greater height, faster growth rates) and had larger and thinner leaves (greater SLA). We found large (average 63%) and trait-dependent (ranging from 14% for LNC to 95.8% for growth rate) genetic variability. The relative extent of genetic variability was greater for whole-plant than for organ-level traits. This pattern was consistent within ecotypes and within cultivars. However, ecotypes presented greater ITV variability., Conclusions: The results indicated that genetic diversity is large in domesticated species with contrasting levels of heritability among functional traits and that selection for high yield has led to indirect selection of some associated leaf traits. These findings open the way to define which target traits should be the focus in selection programs, especially in the context of community-level selection., (© 2017 Botanical Society of America.)

According to predicted changes in climate, waterlogging events may occur more frequently in the future during autumn and winter at high latitudes of the Northern Hemisphere. If excess soil water coincides with the process of cold acclimation for plants, winter survival may potentially be affected. The effects of waterlogging during cold acclimation on stomatal aperture, relative water content, photochemical activity of photosystem II, freezing tolerance and plant regrowth after freezing were compared for two prehardened overwintering forage grasses, Lolium perenne and Festuca pratensis. The experiment was performed to test the hypothesis that changes in photochemical activity initiated by waterlogging-triggered modifications in the stomatal aperture contribute to changes in freezing tolerance. Principal component analysis showed that waterlogging activated different adaptive strategies in the two species studied. The increased freezing tolerance of F. pratensis was associated with increased photochemical activity connected with stomatal opening, whereas freezing tolerance of L. perenne was associated with a decrease in stomatal aperture. In conclusion, waterlogging-triggered stomatal behavior contributed to the efficiency of the cold acclimation process in L. perenne and F. pratensis., (Copyright © 2016 Elsevier Masson SAS. All rights reserved.)

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 Spain to northernmost Finland and Greenland. Ploidy seemed to be positively and negatively correlated with latitude and productivity, respectively. However, the correlations were nonlinear; 84% of the plants were hexaploids (2n = 6x = 42), and the positive correlation between ploidy level and latitude is the result of only four populations skewing the data. In the southernmost end of the gradient 86% of the plants were tetraploids (2n = 4x = 28), whereas in the northernmost end of the gradient one population had only octoploid plants (2n = 8x = 56). Endophytes were detected in 22 out of the 29 populations. Endophyte frequencies varied among geographic sites, and populations and habitats within geographic sites irrespective of ploidy, latitude or productivity. The highest overall endophyte frequencies were found in the southernmost end of the gradient, Spain, where 69% of plants harbored endophytes. In northern Finland, endophytes were detected in 30% of grasses but endophyte frequencies varied among populations from 0% to 75%, being higher in meadows compared to riverbanks. The endophytes were detected in 36%, 30% and 27% of the plants in Faroe Islands, Iceland and Switzerland, respectively. Practically all examined plants collected from southern Finland and Greenland were endophyte-free, whereas in other geographic sites endophyte frequencies were highly variable among populations. Common to all populations with high endophyte frequencies is heavy vertebrate grazing. We propose that the detected endophyte frequencies and ploidy levels mirror past distribution history of F. rubra after the last glaciation period, and local adaptations to past or prevailing selection forces such as vertebrate grazing., Competing Interests: The authors have declared that no competing interests exist.

Background and Aims: Rhizomes are underground stems with meristematic tissues capable of generating shoots and roots. However, mechanisms controlling rhizome formation and growth are yet to be completely understood. The objectives of this study were to investigate whether rhizome development could be regulated by cytokinins (CKs) and gibberellic acids (GAs), and determine underlying mechanisms of regulation of rhizome formation and growth of tall fescue (Festuca arundinacea) by a CK or GA through proteomic and transcript analysis., Methods: A rhizomatous genotype of tall fescue ('BR') plants were treated with 6-benzylaminopurine (BAP, a synthetic cytokinin) or GA3 in hydroponic culture in growth chambers. Furthermore, comparative proteomic analysis of two-dimensional electrophoresis and mass spectrometry were performed to investigate proteins and associated metabolic pathways imparting increased rhizome number by BAP and rhizome elongation by GA3 KEY RESULTS: BAP stimulated rhizome formation while GA3 promoted rhizome elongation. Proteomic analysis identified 76 differentially expressed proteins (DEPs) due to BAP treatment and 37 DEPs due to GA3 treatment. Cytokinin-related genes and cell division-related genes were upregulated in the rhizome node by BAP and gibberellin-related and cell growth-related genes in the rhizome by GA3 CONCLUSIONS: Most of the BAP- or GA-responsive DEPs were involved in respiratory metabolism and amino acid metabolism. Transcription analysis demonstrated that genes involved in hormone metabolism, signalling pathways, cell division and cell-wall loosening were upregulated by BAP or GA3 The CK and GA promoted rhizome formation and growth, respectively, by activating metabolic pathways that supply energy and amino acids to support cell division and expansion during rhizome initiation and elongation in tall fescue., (© The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

The study was aimed to examine the effects of soil amendment with organic waste materials on the growth of red fescue and the uptake of Cu and Zn by this grass, in view of its potential usage for phytostabilization of Cu-polluted soils. Five soils, containing 301-5180 mg/kg Cu, were collected from the surroundings of copper smelter Legnica, and amended with lignite (LG) and limed sewage sludge (SS). Plant growth and the concentrations of Cu and Zn in the shoots and roots of grass were measured in a pot experiment and related to the results of Pytotoxkit and Microtox® tests performed on soil solution. The effects of soil amendment with LG and SS differed greatly, and depended on soil properties. In some cases, the application of alkaline SS resulted in dramatic increase of Cu phytotoxicity and its enhanced uptake by plants, while application of LG to slightly acidic soil caused increased accumulation of Zn in plants, particularly in their roots. The study confirmed good suitability of red fescue for phytostabilization of Cu-contaminated soils except for those extremely polluted. Organic amendments to be used for metal immobilization should be thoroughly examined prior to application.

Leaf elongation rate (LER) is an important factor controlling plant growth and productivity. The objective of this study was to determine whether genetic variation in LER for a fast-growing ('K-31'), and a dwarf cultivar ('Bonsai') of tall fescue (Festuca arundinacea) and gibberellic acid (GA) regulation of LER were associated with differential expression of cell-expansion genes. Plants were treated with GA3, trinexapac-ethyl (TE) (GA inhibitor), or water (untreated control) in a hydroponic system. LER of 'K-31' was 63% greater than that of 'Bonsai', which corresponded with 32% higher endogenous GA4 content in leaf and greater cell elongation and production rates under the untreated control condition. Exogenous application of GA3 significantly enhanced LER while TE treatment inhibited leaf elongation due to GA3-stimulation or TE-inhibition of cell elongation and production rate in leaves for both cultivars. Real-time quantitative polymerase chain reaction analysis revealed that three α-expansins, one β-expansin, and three xyloglucan endotransglycosylase (XET) genes were associated with GA-stimulation of leaf elongation, of which, the differential expression of EXPA4 and EXPA7 was related to the genotypic variation in LER of two cultivars. Those differentially-expressed expansin and XET genes could play major roles in genetic variation and GA-regulated leaf elongation in tall fescue.

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. Whereas endophyte infection increased tall fescue performance in general, the effects of endophytes on plant growth and reproduction varied among plant origins under different environmental conditions. Naturally endophyte-free Finnish cultivar 'Retu' performed equally well as 'Kentucky-31' in both geographic locations. All Eurasian origin plants performed well in the US. In Finland, plants established well and both cultivars survived over the first winter. However, winter mortality of 'Kentucky-31' plants was higher, particularly in fertilized soils in the subsequent winters. Our results suggest that tall fescue ecotype 'Kentucky-31' that flourishes in North America is poorly adapted to Northern European conditions.

The effects of ultrasonic treatments on the germination and seedling growth of aged tall fescue (Festuca arundinacea) and Russian wild rye (Psathyrostaehys juncea Nevski) seeds were determined using orthogonal matrix experimental design with four ultrasonic factors. The multivariate analysis of variance detected significant differences and coupling effects of the pair-wise factors. The activities of Superoxide Dismutase (SOD) and Peroxidase (POD) and the Malondialdehyde (MDA) content were affected. The ultrasonic treatments had positive effects on the germination percentage (GP) of the aged seeds and the growth of the seedlings (GS) and therefore we provided a basic evidence for the application of ultrasonic treatment to pretreat aged grass seeds. For the four ultrasonic factors, the optimal conditions were a sonication time of 36.7 min, a sonication temperature of 35 °C, an output power of 367 W and a seed soaking time 4.1 h after binary quadratic regressions analyses. The ultrasonic treatment has the potential to improve seedling growth. Moreover, the longevity of the tall fescue and the Russian wild rye seeds was approximately 9.5 and 11.5 years, respectively, under natural conditions of storage. The physiological mechanisms that might contribute to the improved GP and GS were discussed.

Invasive, exotic grasses are increasing in tallgrass prairie and their dominance may be contributing to the decline of grassland butterflies through alterations in forage quality. Tall fescue (Schedonorus arundinaceus (Schreb.) Dumort.), an exotic grass covering millions of acres in the United States, can host a fungal endophyte, Epichloë coenophiala (Morgan-Jones & Gams). Alkaloids produced by the endophyte are known to be toxic to some foliar-feeding pest insects. Endophyte-infected tall fescue is commonly planted in hayfields, pastures, lawns, and is invading natural areas, but effects of the endophyte on nonpest insects such as butterflies are relatively unknown. Our objective was to investigate the role that tall fescue and its endophyte might play in the decline of grass skippers (Hesperiidae). We examined growth and survival parameters of tawny-edged skippers (Polites themistocles (Latreille)) that were reared on endophyte-infected tall fescue (E+), endophyte-free tall fescue (E-), and Kentucky bluegrass (KBG). KBG was included as a comparison because it is a cool season grass known to be palatable to P. themistocles larvae. Interestingly, results showed that the endophyte did not affect growth and survival of larvae compared to uninfected tall fescue, even though significant amounts of loline alkaloids (average 740 ppm) were measured in endophyte-infected plant material. Larvae feeding on KBG grew faster with greater survival rates than larvae on both tall fescue treatments. These results confirm that tall fescue invasion and dominance may be deteriorating the quality of grassland habitats for native pollinators; however, this effect does not appear to be linked to endophyte infection., (© The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)