Transcriptome Analysis of Wounding in the Model Grass Lolium temulentum

For forage and turf grasses, wounding is a predominant stress that often results in extensive loss of vegetative tissues followed by rapid regrowth. Currently, little is known concerning the perception, signaling, or molecular responses associated with wound stress in forage- and turf-related grasses. A transcriptome analysis of Lolium temulentum plants subjected to severe wounding revealed 9413 upregulated and 7704 downregulated, distinct, differentially expressed genes (DEGs). Categories related to signaling, transcription, and response to stimuli were enriched in the upregulated DEGs. Specifically, sequences annotated as enzymes involved in hormone biosynthesis/action and cell wall modifications, mitogen-activated protein kinases, WRKY transcription factors, proteinase inhibitors, and pathogen defense-related DEGs were identified. Surprisingly, DEGs related to heat shock and chaperones were more prevalent in the downregulated DEGs when compared with the upregulated DEGs. This wound transcriptome analysis is the first step in identifying the molecular components and pathways used by grasses in response to wounding. The information gained from the analysis will provide a valuable molecular resource that will be used to develop approaches that can improve the recovery, regrowth, and long-term fitness of forage and turf grasses before/after cutting or grazing.

Evaluation of production efficiencies at pasture of lactating suckler cows of diverse genetic merit and replacement strategy

Feed costs account for the largest proportion of direct cost within suckler beef production systems. By identifying the cow type with enhanced capability of converting grazed herbage to beef output across lactations, suckler cow systems would become more efficient and sustainable. The objective of this study was to estimate grass DM intake (GDMI) and production efficiency among lactating suckler cows of diverse genetic merit for the national Irish maternal index (Replacement Index) which includes cow efficiency components such as milk yield and feed intake. Data from 131 cows of diverse genetic merit within the Replacement Index, across two different replacement strategies (suckler or dairy sourced), were available over two grazing seasons. Milk yield, GDMI, cow live weight (BW) and body condition score (BCS) were recorded during early, mid and late-lactation, with subsequent measures of production efficiency extrapolated. Genetic merit had no significant effect on any variables investigated, with the exception of low genetic merit (LOW) cows being 22 kg heavier in BW than high genetic merit (HIGH) cows (P < 0.05). Beef cows were 55 kg heavier in BW (P < 0.001), had a 0.31 greater BCS (P < 0.05) and 0.30 Unité Fourragère Lait (UFL) greater energy requirement for maintenance compared to dairy sourced beef × dairy crossbred (BDX) cows (P < 0.001). The BDX had 0.8 kg greater GDMI, produced 1.8 kg more milk (P < 0.001), had a 0.8 UFL greater energy requirement for lactation and produced weanlings that were 17 kg heavier in BW than beef cows (P < 0.05). Subsequent efficiency variables of milk per 100 kg BW (P < 0.001), milk per kg GDMI (P < 0.001) and GDMI per 100 kg BW (P < 0.001) were more favourable for BDX. The correlations examined showed GDMI had moderate positive correlations (P < 0.001) with intake per 100 kg BW, net energy intake per kg milk yield, RFI and intake per 100 kg calf weaning weight but was weakly negatively correlated to milk yield per kg GDMI (P < 0.001). No difference was observed across genetic merit for beef cows for any of the traits investigated. Results from the current study showed that, while contrasting replacement strategies had an effect on GDMI and production efficiency, no main effect was observed on cows diverse in genetic merit for Replacement Index. Nonetheless, utilising genetic indexes in the suckler herd is an important resource for selecting breeding females for the national herd and phenotypic performance generated from this study can be included in future genetic evaluations to improve reliability of genetic values.

A unified framework for plant life-history strategies shaped by fire and herbivory

Fire and herbivory both remove aboveground biomass. Environmental factors determine the type and intensity of these consumers globally, but the traits of plants can also alter their propensity to burn and the degree to which they are eaten. To understand plant life-history strategies associated with fire and herbivory we need to describe both response and effect functional traits, and how they sort within communities, along resource gradients, and across evolutionary timescales. Fire and herbivore functional traits are generally considered separately, but there are advances made in understanding fire that relate to herbivory, and vice versa. Moreover, fire and herbivory interact: the presence of one consumer affects the type and intensity of the other. Here, we present a unifying conceptual framework to understand plant strategies that enable tolerance and persistence to fire and herbivory. Using grasses as an example, we discuss how flammability and fire tolerance, palatability, and grazing tolerance traits might organize themselves in ecosystems exposed to these consumers, and how these traits might have evolved with reference to other strong selective processes, like aridity. Our framework can be used to predict both the diversity of life-history strategies and plant species diversity under different consumer regimes.

Persistence of the clinical effect of grass allergen peptide immunotherapy after the second and third grass pollen seasons

BACKGROUND

Grass allergen peptides are in development for the treatment of grass pollen-induced allergic rhinoconjunctivitis. A previous randomized, placebo-controlled study demonstrated that grass allergen peptides significantly improved total rhinoconjunctivitis symptom scores (TRSSs) after posttreatment challenge (PTC) to rye grass in an environmental exposure unit after 1 intervening grass pollen season (GPS1).

OBJECTIVE

We sought to evaluate the efficacy/safety of 4 dosing regimens of grass allergen peptides after a second (GPS2) and third (GPS3) intervening GPS in the environmental exposure unit.

METHODS

Eligible subjects who were randomized in the parent study (GPS1) during the first year of recruitment were invited to participate in GPS2 and GPS3, which took place 1 and 2 years after treatment cessation, respectively. Participants were not treated further, and both participants and study personnel remained blinded. The primary efficacy end point was the change in mean TRSS (reported every 30 minutes) from GPS1 baseline to the follow-up PTC calculated across all time points over days 2 to 4 for GPS2 and across hours 1 to 3 over days 2 to 4 for GPS3. Secondary efficacy end points and safety were also assessed.

RESULTS

One hundred twenty-two and 85 participants were enrolled in GPS2 and GPS3, respectively. A numerically greater, but not statistically significant improvement from baseline in mean TRSS at PTC was observed in the group receiving one 6-nmol intradermal injection every 2 weeks for 14 weeks group compared with the placebo at GPS2 (-6.0 vs -3.6, P = .0535) and GPS3 (-6.2 vs -3.6, P = .1128). Similar findings were observed for the group receiving one 6-nmol intradermal injection every 2 weeks for 14 weeks at GPS3 (-6.4 vs -3.6, P = .0759). No adverse safety signals were detected.

CONCLUSION

Treatment with grass allergen peptides led to an improvement in allergic rhinoconjunctivitis symptoms after 3 intervening GPSs, corresponding to up to 2 years off treatment.

Shrub persistence and increased grass mortality in response to drought in dryland systems

Droughts in the southwest United States have led to major forest and grassland die-off events in recent decades, suggesting plant community and ecosystem shifts are imminent as native perennial grass populations are replaced by shrub- and invasive plant-dominated systems. These patterns are similar to those observed in arid and semiarid systems around the globe, but our ability to predict which species will experience increased drought-induced mortality in response to climate change remains limited. We investigated meteorological drought-induced mortality of nine dominant plant species in the Colorado Plateau Desert by experimentally imposing a year-round 35% precipitation reduction for eight continuous years. We distributed experimental plots across numerous plant, soil, and parent material types, resulting in 40 distinct sites across a 4,500 km² region of the Colorado Plateau Desert. For all 8 years, we tracked c. 400 individual plants and evaluated mortality responses to treatments within and across species, and through time. We also examined the influence of abiotic and biotic site factors in driving mortality responses. Overall, high mortality trends were driven by dominant grass species, including Achnatherum hymenoides, Pleuraphis jamesii, and Sporobolus cryptandrus. Responses varied widely from year to year and dominant shrub species were generally resistant to meteorological drought, likely due to their ability to access deeper soil water. Importantly, mortality increased in the presence of invasive species regardless of treatment, and native plant die-off occurred even under ambient conditions, suggesting that recent climate changes are already negatively impacting dominant species in these systems. Results from this long-term drought experiment suggest major shifts in community composition and, as a result, ecosystem function. Patterns also show that, across multiple soil and plant community types, native perennial grass species may be replaced by shrubs and invasive annuals in the Colorado Plateau Desert.

Extreme Diversity of Mycoviruses Present in Isolates of Rhizoctonia solani AG2-2 LP From Zoysia japonica From Brazil

Zoysia japonica, in Brazil, is commonly infected by Rhizoctonia solani (R. solani) in humid and cool weather conditions. Eight isolates of R. solani, previously identified as belonging to the AG2-2 LP anastomosis group, isolated from samples from large path symptoms, were collected from three counties in São Paulo state (Brazil) and investigated for the presence of mycoviruses. After detection of double-strand RNA (dsRNA) in all samples, RNA_Seq analysis of ribosomal RNA-depleted total RNA from in vitro cultivated mycelia was performed. Forty-seven partial or complete viral unique RNA dependent-RNA polymerase (RdRp) sequences were obtained with a high prevalence of positive sense ssRNA viruses. Sequences were sufficiently different from the first match in BLAST searches suggesting that they all qualify as possible new viral species, except for one sequence showing an almost complete match with Rhizoctonia solani dsRNA virus 2, an alphapartitivirus. Surprisingly four large contigs of putative viral RNA could not be assigned to any existing clade of viruses present in the databases, but no DNA was detected corresponding to these fragments confirming their viral replicative nature. This is the first report on the occurrence of mycoviruses in R. solani AG2-2 LP in South America.

Clothing the Emperor: Dynamic Root-Shoot Allocation Trajectories in Relation to Whole-Plant Growth Rate and in Response to Temperature

We quantified how root-shoot biomass allocation and whole-plant growth rate co-varied ontogenetically in contrasting species in response to cooling. Seven grass and four forb species were grown for 56 days in hydroponics. Growth was measured repeatedly before and after day/night temperatures were reduced at 28 days from 20 °C/15 °C to 10 °C/5 °C; controls remained unchanged. Sigmoid trajectories of root and shoot growth were reconstructed from the experimental data to derive continuous whole-plant relative growth rates (RGRs) and root mass fractions (RMFs). Root mass fractions in cooled plants generally increased, but this originated from unexpected and previously uncharacterised differences in response among species. Root mass fraction and RGR co-trajectories were idiosyncratic in controls and cooled plants. The RGR-RMF co-trajectories responded to cooling in grasses, but not forbs. The RMF responses of stress-tolerant grasses were predictably weak but projected to eventually out-respond faster-growing species. Sigmoid growth constrains biomass allocation. Only when neither root nor shoot biomass is near-maximal can biomass allocation respond to environmental drivers. Near maximum size, plants cannot adjust RMF, which then reflects net above- and belowground productivities. Ontogenetic biomass allocations are not equivalent to those based on interspecific surveys, especially in mature vegetation. This reinforces the importance of measuring temporal growth dynamics, and not relying on "snapshot" comparisons to infer the functional significance of root-shoot allocation.

Proteomic Profiling for Metabolic Pathways Involved in Interactive Effects of Elevated Carbon Dioxide and Nitrogen on Leaf Growth in a Perennial Grass Species

Elevated atmospheric CO₂ and nitrogen are major environmental factors affecting shoot growth. The objectives of this study are to determine the interactive effects of elevated CO₂ and nitrogen on leaf growth in tall fescue ( Festuca arundinacea) and to identify major proteins and associated metabolic pathways underlying CO₂-regulation of leaf growth under insufficient and sufficient nitrate conditions using proteomic analysis. Plants of tall fescue treated with low nitrate level (0.25 mM, LN), moderate nitrate level (4 mM, MN) and high nitrate level (32 mM, HN) were exposed to ambient (400 μmol mol^-1) and elevated (800 μmol mol^-1) CO₂ concentrations in environment-controlled growth chambers. Increased atmospheric CO₂ concentration increased leaf length and shoot biomass, which corresponded to increased content of indo-acetic acid, gibberellic acid, cytokinins and reduced content of abscisic acid under sufficient nitrate conditions (MN and HN conditions). Low nitrate supply limited shoot growth and hormonal responses to elevated CO₂. Proteomic analysis of plants exposed to elevated CO₂ under LN and MN conditions demonstrated the increases in the abundance of many proteins due to elevated CO₂ under MN condition involved with cell cycle and proliferation, transcription and translation, photosynthesis (ribosomal and chlorophyll a/b-binding proteins), amino acids synthesis, sucrose and starch metabolism, as well as ABA signaling pathways (ABA-induced proteins). Our results revealed major proteins and associated metabolic pathways associated with the interactive effects of elevated CO₂ and nitrate regulating leaf growth in a perennial grass species.

OsMYB108 loss-of-function enriches p-coumaroylated and tricin lignin units in rice cell walls

Breeding approaches to enrich lignins in biomass could be beneficial to improving the biorefinery process because lignins increase biomass heating value and represent a potent source of valuable aromatic chemicals. However, despite the fact that grasses are promising lignocellulose feedstocks, limited information is yet available for molecular-breeding approaches to upregulate lignin biosynthesis in grass species. In this study, we generated lignin-enriched transgenic rice (Oryza sativa), a model grass species, via targeted mutagenesis of the transcriptional repressor OsMYB108 using CRISPR/Cas9-mediated genome editing. The OsMYB108-knockout rice mutants displayed increased expressions of lignin biosynthetic genes and enhanced lignin deposition in culm cell walls. Chemical and two-dimensional nuclear magnetic resonance (NMR) analyses revealed that the mutant cell walls were preferentially enriched in γ-p-coumaroylated and tricin lignin units, both of which are typical and unique components in grass lignins. NMR analysis also showed that the relative abundances of major lignin linkage types were altered in the OsMYB108 mutants.

Strigolactones Promote Leaf Elongation in Tall Fescue through Upregulation of Cell Cycle Genes and Downregulation of Auxin Transport Genes in Tall Fescue under Different Temperature Regimes

Strigolactones (SLs) have recently been shown to play roles in modulating plant architecture and improving plant tolerance to multiple stresses, but the underlying mechanisms for SLs regulating leaf elongation and the influence by air temperature are still unknown. This study aimed to investigate the effects of SLs on leaf elongation in tall fescue (Festuca arundinacea, cv. ‘Kentucky-31’) under different temperature regimes, and to determine the interactions of SLs and auxin in the regulation of leaf growth. Tall fescue plants were treated with GR24 (synthetic analog of SLs), naphthaleneacetic acid (NAA, synthetic analog), or N-1-naphthylphthalamic acid (NPA, auxin transport inhibitor) (individually and combined) under normal temperature (22/18 °C) and high-temperature conditions (35/30 °C) in controlled-environment growth chambers. Exogenous application of GR24 stimulated leaf elongation and mitigated the heat inhibition of leaf growth in tall fescue. GR24-induced leaf elongation was associated with an increase in cell numbers, upregulated expression of cell-cycle-related genes, and downregulated expression of auxin transport-related genes in elongating leaves. The results suggest that SLs enhance leaf elongation by stimulating cell division and interference with auxin transport in tall fescue.

Soil Bacterial Function Associated With Stylo (Legume) and Bahiagrass (Grass) Is Affected More Strongly by Soil Chemical Property Than by Bacterial Community Composition

Soil microbes are driver of nutrient cycling, with microbial function affected by community composition and soil chemical property. Legume and grass are ubiquitous in many ecosystems, however, their differential effects on microbial function are less understood. Here we constructed compartmented rhizobox planted with stylo (Stylosanthes guianensis, legume) or bahiagrass (Paspalum natatum, grass) to compare their influences on bacterial function and to investigate the determinant of bacterial function. Soils in root compartment and in near (0–5 mm from root compartment) or far (10–15 mm from root compartment) rhizosphere were sampled. Soil chemical properties, bacterial community composition and function were characterized. Results indicate that plant species and distance significantly affected bacterial function. The activities of beta-xylosidase, nitrate reductase and phosphomonoesterase were higher in stylo soil than in bahiagrass soil, while leucine-aminopeptidase activity and nosZ abundance were vice versa. Rhizosphere effect was obvious for the activities of beta-glucosidase, beta-xylosidase, chitinase, and the abundances of AOB-amoA, nirS, nosZ. Statistical analysis revealed that soil chemical property was significantly associated with bacterial function, with a higher coefficient than bacterial community composition. These data suggest that stylo and bahiagrass differentially affect bacterial function, which is affected more strongly by soil chemical property than by community composition.

Agrobacterium-Mediated Transformation of Brachypodium distachyon

Brachypodium distachyon is an excellent model system for the grasses and has been adopted as a research organism by many laboratories around the world. It has all of the biological traits required for a model system, including small stature, short life cycle, small genome, simple growth requirements, and a close relationship to major crop plants (cereals). In addition, numerous resources have been developed for working with this species, including genome sequences for many lines, sequenced mutant collections, and a large, freely available germplasm collection. Fortunately, among grasses B. distachyon is one of the most easily transformed species, an absolute necessity for a model system. Agrobacterium-mediated transformation is the preferred method to transform plants because it usually results in simple insertions of target DNA. In this article, we describe a method for Agrobacterium-mediated transformation of the inbred B. distachyon lines Bd21 and Bd21-3. Embryogenic callus induced from immature embryos is co-cultivated with Agrobacterium tumefaciens strain AGL1 or Agrobacterium rhizogenes strain 18r12v. Hygromycin and paromomycin are used as selective agents, with comparable transformation efficiencies (defined as the percentage of co-cultivated callus that produce transgenic plants) of 40% to 70%. It takes 20 to 30 weeks to obtain T₁ seeds starting from the initial step of dissecting out immature embryos. This protocol has been shown to be efficient and facile in several studies that resulted in the creation of over 22,000 T-DNA mutants. © 2019 by John Wiley & Sons, Inc.

Alternate Grassy Ecosystem States Are Determined by Palatability-Flammability Trade-Offs

Fire and mammalian grazers both consume grasses, and feedbacks between grass species, their functional traits, and consumers have profound effects on grassy ecosystem structure worldwide, such that savanna and grassland states determined by fire or grazing can be considered alternate states. These parallel savanna-forest alternate states, which likewise have myriad cascading ecosystem impacts.

Lignin characterization of rice CONIFERALDEHYDE 5-HYDROXYLASE loss-of-function mutants generated with the CRISPR/Cas9 system

The aromatic composition of lignin is an important trait that greatly affects the usability of lignocellulosic biomass. We previously identified a rice (Oryza sativa) gene encoding coniferaldehyde 5-hydroxylase (OsCAld5H1), which was effective in modulating syringyl (S)/guaiacyl (G) lignin composition ratio in rice, a model grass species. Previously characterized OsCAld5H1-knockdown rice lines, which were produced via an RNA-interference approach, showed augmented G lignin units yet contained considerable amounts of residual S lignin units. In this study, to further investigate the effect of suppression of OsCAld5H1 on rice lignin structure, we generated loss-of-function mutants of OsCAld5H1 using the CRISPR/Cas9-mediated genome editing system. Homozygous OsCAld5H1-knockout lines harboring anticipated frame-shift mutations in OsCAld5H1 were successfully obtained. A series of wet-chemical and two-dimensional NMR analyses on cell walls demonstrated that although lignins in the mutant were predictably enriched in G units all the tested mutant lines produced considerable numbers of S units. Intriguingly, lignin γ-p-coumaroylation analysis by the derivatization followed by reductive cleavage method revealed that enrichment of G units in lignins of the mutants was limited to the non-γ-p-coumaroylated units, whereas grass-specific γ-p-coumaroylated lignin units were almost unaffected. Gene expression analysis indicated that no homologous genes of OsCAld5H1 were overexpressed in the mutants. These data suggested that CAld5H is mainly involved in the production of non-γ-p-coumaroylated S lignin units, common in both eudicots and grasses, but not in the production of grass-specific γ-p-coumaroylated S units in rice.

A Survey of Culturable Fungal Endophytes From Festuca rubra subsp. pruinosa, a Grass From Marine Cliffs, Reveals a Core Microbiome

Festuca rubra subsp. pruinosa is a perennial grass that inhabits sea cliffs of the Atlantic coasts of Europe. In this unhospitable environment plants grow in rock crevices and are exposed to abiotic stress factors such as low nutrient availability, wind, and salinity. Festuca rubra subsp. pruinosa is a host of the fungal endophyte Epichloë festucae, which colonizes aerial organs, but its root mycobiota is unknown. The culturable endophytic mycobiota of FRP roots was surveyed in a set of 105 plants sampled at five populations in marine cliffs from the northern coast of Spain. In total, 135 different fungal taxa were identified, 17 of them occurred in more than 10% of plants and in two or more populations. Seven taxa belonging to Fusarium, Diaporthe, Helotiales, Drechslera, Slopeiomyces, and Penicillium appeared to be constituents of the core microbiome of Festuca rubra subsp. pruinosa roots because they occurred in more than 20% of the plants analyzed, and at three or more populations. Most fungal strains analyzed (71.8%) were halotolerant. The presence of Epichloë festucae in aboveground tissue was detected in 65.7% of the plants, but its presence did not seem to significantly affect the structure of the core or other root microbiota, when compared to that of plants free of this endophyte. When plants of the grass Lolium perenne were inoculated with fungal strains obtained from Festuca rubra subsp. pruinosa roots, a Diaporthe strain significantly promoted leaf biomass production under normal and saline (200 mM NaCl) watering regimes. These results suggest that the core mycobiome of Festuca rubra subsp. pruinosa could have a role in host plant adaptation, and might be useful for the improvement of agricultural grasses.

Silicon Supplementation of Rescuegrass Reduces Herbivory by a Grasshopper

The theory of coevolution suggests that herbivores play an important role in the diversification and composition of plant communities. A prevalent idea holds that grasses and grazing animals participated in an evolutionary "arms race" as grassland ecosystems started spreading across the continents. In this race, besides other things, silicification in the form of phytoliths occurred in the grasses, and the graminivorous herbivores responded through specialized mandibles to feed on plants rich in phytoliths. It is important to understand whether these mandibles equip the herbivores in different environments or the grasses can augment their defense by channelizing their energy in high resource milieu. Here we used rescuegrass (Bromus catharticus; Family: Poaceae), an alien species of South America, to understand the mechanism of resistance offered by this species against a local insect herbivore (Oxya grandis; Family: Acrididae), graminivorous grasshopper, in different silicon-rich environments. We used different concentrations of silicon and observed the types of phytoliths formed after Si amendments and studied the effect of phytoliths on mandible wear of the grasshopper. Silicon concentrations increased ca. 12 fold in the highest supplementation treatments. The results reveal that higher foliar silica concentration in Si-rich plants did not result in changing the morphology of the phytoliths; still the leaf tissue consumption was lower in higher Si treatments, perhaps due to mandibular wear of the grasshoppers. The study opens a new dimension of investigating the role of Si amendments in reducing herbivory.

Drawing a Line: Grasses and Boundaries

Delineation between distinct populations of cells is essential for organ development. Boundary formation is necessary for the maintenance of pluripotent meristematic cells in the shoot apical meristem (SAM) and differentiation of developing organs. Boundaries form between the meristem and organs, as well as between organs and within organs. Much of the research into the boundary gene regulatory network (GRN) has been carried out in the eudicot model Arabidopsis thaliana. This work has identified a dynamic network of hormone and gene interactions. Comparisons with other eudicot models, like tomato and pea, have shown key conserved nodes in the GRN and species-specific alterations, including the recruitment of the boundary GRN in leaf margin development. How boundaries are defined in monocots, and in particular the grass family which contains many of the world’s staple food crops, is not clear. In this study, we review knowledge of the grass boundary GRN during vegetative development. We particularly focus on the development of a grass-specific within-organ boundary, the ligule, which directly impacts leaf architecture. We also consider how genome engineering and the use of natural diversity could be leveraged to influence key agronomic traits relative to leaf and plant architecture in the future, which is guided by knowledge of boundary GRNs.

C4 anatomy can evolve via a single developmental change

C₄ photosynthesis is a complex trait that boosts productivity in warm environments. Paradoxically, it evolved independently in numerous plant lineages, despite requiring specialised leaf anatomy. The anatomical modifications underlying C₄ evolution have previously been evaluated through interspecific comparisons, which capture numerous changes besides those needed for C₄ functionality. Here, we quantify the anatomical changes accompanying the transition between non‐C₄ and C₄ phenotypes by sampling widely across the continuum of leaf anatomical traits in the grass Alloteropsis semialata. Within this species, the only trait that is shared among and specific to C₄ individuals is an increase in vein density, driven specifically by minor vein development that yields multiple secondary effects facilitating C₄ function. For species with the necessary anatomical preconditions, developmental proliferation of veins can therefore be sufficient to produce a functional C₄ leaf anatomy, creating an evolutionary entry point to complex C₄ syndromes that can become more specialised.

Differences in the Nasal Inflammatory Response to Cynodon dactylon From Rural and Urban Areas in Patients With Allergic Rhinitis

Background

Epidemiological and experimental studies suggest that air pollution has a negative impact on human health and modifies the environment. However, the clinical implications of changes in environmental allergens secondary to air pollution have been little studied.

Objectives

To explore if the growth conditions of the Cynodon dactylon (rural vs urban area) modify the inflammatory response among patients with allergic rhinitis.

Methodology: Two extracts were prepared for diagnostic test with Cyn d proteins obtained from rural and urban environment. Skin prick test (SPT), nasal challenge test (NCT), and eosinophil count in nasal mucus were performed in 3 groups: healthy subjects without rhinitis, rhinitis with (+) Cyn d, and rhinitis with (−) Cyn d.

Results

There was a 97% concordance in the positive and negative results of the SPT with the 2 extracts. However, Cyn d-urban extract generated larger wheals (P = .03) and a higher number of patients with rhinitis presented a positive NCT to this extract (n = 7 vs 14, P = .04). Patients with positive NCT had a significant increase in eosinophils in mucus, but there was no difference between the extracts. The healthy controls did not react to the extracts tested in the skin or nasal test.

Conclusion

The findings suggest that the growth conditions in urban area of Cynodon dactylon can generate changes in the protein extract and have clinical implications in patients with allergic rhinitis.

The effect of landing surface on landing error scoring system grades

Different landing surfaces may affect lower extremity biomechanical performance during athletic tasks. The magnitude of this effect on clinical screening measures such as jump-landings is unknown. This study determined the effect of court (CS), grass (GS), and tile (TS) surfaces on Landing Error Scoring System (LESS) grades. A repeated-measures design was used. A total of 40 (21F, 19M; mean age = 23.8 ± 2.4 yr) recreational athletes performed a jump-landing task on three different landing surfaces. 2D videography recorded jump-landings in the frontal and sagittal planes. A 2 × 3 (sex by surface) mixed-model repeated-measures analysis of variance was used to examine main and interaction effects associated with surface and sex. No significant sex by landing surface interactions existed for LESS grades. No significant differences were observed on LESS grades for the main effect of surface (CS = 4.83 ± 1.31 points; GS = 5.01 ± 1.40 points; TS = 5.09 ± 1.86 points; all p > 0.05). Correlations were found between LESS grades among different conditions (r range = 0.587-0.611; all p < 0.001). Commonly used jump-landing surfaces for clinical biomechanical evaluations do not affect LESS grades, suggesting generalisability as a screening tool for anterior cruciate ligament injury risk in different sport environments.

Application of Energy Dispersive X-ray Fluorescence Spectrometry to the Determination of Copper, Manganese, Zinc, and Sulfur in Grass ( Lolium perenne) in Grazed Agricultural Systems

Conventional methods for the determination of major nutrients and trace elements in grass rely on acid digestion followed by analysis using inductively coupled plasma optical emission spectrometry (ICP-OES), which can be both time consuming and costly. Energy dispersive X-ray fluorescence (EDXRF) spectrometry offers a rapid alternative that can determine multiple elements in a single scan. Copper, Mn, Zn, and S in grass samples were determined using EDXRF with a number of different calibration approaches using both empirical standards and the theoretical relationships between concentrations and intensities. Using an existing archive of 467 grass samples of known concentrations, a suite of 30 samples was selected as empirical grass standards to build a calibration set between sample concentrations and EDXRF intensities. The theoretical or standardless approach used the fundamental parameters method to determine element concentrations. To validate the two calibration methods, 59 samples were randomly selected from the same archive and database and analyzed by EDXRF. The measurements of Cu, Mn, Zn, and S were compared with the ICP-OES values using agreement statistics. An excellent correlation was observed between the concentrations determined by EDXRF and ICP-OES ( R > 0.90) regardless of the calibration approach. However, agreement and closeness to the true value varied and were assessed using agreement statistics. Across all elements, the empirically calibrated samples were in excellent agreement with the values determined by ICP-OES. The theoretical calibrations provided excellent agreement for Mn and Zn, but a degree of fixed and proportional bias was observed in the Cu and S values. Fixed bias was corrected by subtracting the computed bias from the EDXRF concentrations and improved the overall agreement. Similarly, proportional bias was corrected using the linear regression model to predict the corrected EDXRF values. This improved the overall agreement with the ICP-OES values for both Cu and S using corrected fundamental parameters calibrations. This study provides a practical basis for the use of EDXRF to determine Cu, Mn, Zn, and S in grass samples to monitor forage quality in grazed systems without the need for sample digestion. The observed fixed and proportional bias in the theoretical calibrations can be corrected provided that a good correlation exists between EDXRF and conventional methods.

Prolonged effect of allergen sublingual immunotherapy to grass pollen

Background: The prolonged effect of allergen immunotherapy is unknown, especially in older patients. Objective: The three-year effect of sublingual allergen-specific immunotherapy (AIT) to grass pollen on elderly patients with allergic rhinitis was analyzed. Methods: Thirty-eight elderly patients (63.18 ± 3.12 yrs.) underwent AIT to grass pollen, were monitored for three years and were compared to a placebo group. AIT was performed with the use of an oral Staloral 300 SR grass extract (Stallergens Greer, London, UK) or a placebo. Symptoms and medication scores, represented by the average adjusted symptom score (AAdSS), the serum level of IgG4 to Phl p5 and the quality of life were assessed immediately after AIT and three years later. Results: After AIT, the AAdSS was significantly decreased and remained lower than in the placebo group during the three years after AIT. Serum-specific IgG4 against Phl p5 increased during the AIT trial in the study group. For the three years of observation after AIT, there were no significant changes in specific IgG4 levels against the analyzed allergens in comparison to the results immediately after AIT. The quality of life, based on the Rhinoconjunctivitis Quality of Life Questionnaire, was significantly decreased in patients who received AIT, from 1.83 (95%CI: 1.45-1.96) to 0.74 (95%CI: 0.39-1.92) (p < 0.05) to 0.82 (95%CI: 0.45- 1.04) three years after AIT. Conclusion: A prolonged positive effect after AIT to grass pollen was observed in elderly patients with allergic rhinitis. Further trials are needed to confirm this effect.

Phytoremediation of BTEX and Naphthalene from produced-water spill sites using Poaceae

Surface spills of water produced from hydraulic fracturing can expose soil and groundwater to organics such as BTEX and naphthalene (BTEX&N) as well as high concentrations of salt. As an alternative to soil excavation, we evaluated the effectiveness of BTEX&N soil remediation using 2 grasses present in Colorado. Perennial ryegrass and foxtail barley were grown separately in pots in the greenhouse and exposed to salt or a synthesized produced-water slurry containing relevant levels of salt and BTEX&N. Plant biomass was measured 14 days post-spill, and levels of BTEX&N were quantified using GC/MS for soil, roots, and shoots at day 7 and 14 post-spill. Foxtail barley shoot growth was limited by BTEX&N, whereas perennial ryegrass shoot growth was enhanced by salt but not BTEX&N. While BTEX&N in soil associated with foxtail barley mainly decreased over time, the soil associated with perennial ryegrass mainly saw an increase in BTEX&N with time. However, further research is needed to determine the fate of BTEX&N within grasses and soil.

Downregulation of p-COUMAROYL ESTER 3-HYDROXYLASE in rice leads to altered cell wall structures and improves biomass saccharification

p-Coumaroyl ester 3-hydroxylase (C3'H) is a key enzyme involved in the biosynthesis of lignin, a phenylpropanoid polymer that is the major constituent of secondary cell walls in vascular plants. Although the crucial role of C3'H in lignification and its manipulation to upgrade lignocellulose have been investigated in eudicots, limited information is available in monocotyledonous grass species, despite their potential as biomass feedstocks. Here we address the pronounced impacts of C3'H deficiency on the structure and properties of grass cell walls. C3'H-knockdown lines generated via RNA interference (RNAi)-mediated gene silencing, with about 0.5% of the residual expression levels, reached maturity and set seeds. In contrast, C3'H-knockout rice mutants generated via CRISPR/Cas9-mediated mutagenesis were severely dwarfed and sterile. Cell wall analysis of the mature C3'H-knockdown RNAi lines revealed that their lignins were largely enriched in p-hydroxyphenyl (H) units while being substantially reduced in the normally dominant guaiacyl (G) and syringyl (S) units. Interestingly, however, the enrichment of H units was limited to within the non-acylated lignin units, with grass-specific γ-p-coumaroylated lignin units remaining apparently unchanged. Suppression of C3'H also resulted in relative augmentation in tricin residues in lignin as well as a substantial reduction in wall cross-linking ferulates. Collectively, our data demonstrate that C3'H expression is an important determinant not only of lignin content and composition but also of the degree of cell wall cross-linking. We also demonstrated that C3'H-suppressed rice displays enhanced biomass saccharification.