scholarly journals Antagonism to Plant Pathogens by Epichloë Fungal Endophytes—A Review

Plants ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1997
Author(s):  
Stuart D. Card ◽  
Daniel A. Bastías ◽  
John R. Caradus
Keyword(s):  
Plant Pathogens ◽  
Fungal Endophytes ◽  
Antimicrobial Properties ◽  
Cool Season ◽  
Symbiotic Associations ◽  
Pathogenic Microbes ◽  
Multiple Species ◽  
Epichloë Endophytes ◽  
Grazing Livestock

Epichloë is a genus of filamentous fungal endophytes that has co-evolved with cool-season grasses with which they form long-term, symbiotic associations. The most agriculturally important associations for pasture persistence for grazing livestock are those between asexual vertically transmitted Epichloë strains and the pasture species, perennial ryegrass, and tall fescue. The fungus confers additional traits to their host grasses including invertebrate pest deterrence and drought tolerance. Selected strains of these mutualistic endophytes have been developed into highly efficacious biocontrol products and are widely utilized within the Americas, Australia, and New Zealand for pasture persistence. Less publicized is the antagonism Epichloë endophytes display towards multiple species of saprophytic and pathogenic microbes. This opinion piece will review the current literature on antimicrobial properties exhibited by this genus of endophyte and discuss the reasons why this trait has historically remained a research curiosity rather than a trait of commercial significance.

scholarly journals Epichloë (formerly Neotyphodium) fungal endophytes increase adaptation of cool-season perennial grasses to environmental stresses

2019 ◽  
Vol 72 (2) ◽  
Author(s):  
Dariusz Piotr Malinowski ◽  
David Paul Belesky
Keyword(s):  
Abiotic Stresses ◽  
Plant Pathogens ◽  
Plant Competition ◽  
Fungal Endophytes ◽  
Secondary Compounds ◽  
Perennial Grasses ◽  
Ecosystem Functions ◽  
Grass Species ◽  
Cool Season ◽  
Host Chemistry

Many cool-season grass species have evolved with asexual, nonsymptomatic fungal endophytes of the genus <em>Epichloë</em> (formerly <em>Neotyphodium</em>) of the family Clavicipitaceae. These associations range from parasitic to mutualistic and have dramatic effects on grass host chemistry, increasing resistance to abiotic (drought, soil mineral imbalance) and biotic (vertebrate and invertebrate herbivory, nematodes, plant pathogens, plant competition) stresses. Native endophyte strains produce a range of bioprotective alkaloid and other nonalkaloid secondary compounds, several of them known to have detrimental effects on grazing animals. In the past two decades, epichloid endophyte strains have been selected with marginal or no capacity of producing ergot and/or lolitrem alkaloids. These novel endophyte strains have been introduced to several grass cultivars with the idea to increase grass host resistance to abiotic stresses without hindering grazing livestock, and abiotic stresses to ensure high competitive ability of symbiotic grass cultivars. In this presentation, we discuss mechanisms underlying the competitiveness of epichloid endophyte/grass associations and consequences of endophyte infection for grassland ecosystem functions.

scholarly journals The Role of Hydraulic Silicate Cements on Long-Term Properties and Biocompatibility of Partial Pulpotomy in Permanent Teeth

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 305
Author(s):  
Chung-Min Kang ◽  
Saemi Seong ◽  
Je Seon Song ◽  
Yooseok Shin
Keyword(s):  
Regression Analysis ◽  
Cox Regression ◽  
Antimicrobial Properties ◽  
Permanent Teeth ◽  
Success Rates ◽  
Pulp Tissue ◽  
Cox Regression Analysis ◽  
Clinical Variables

The use of hydraulic silicate cements (HSCs) for vital pulp therapy has been found to release calcium and hydroxyl ions promoting pulp tissue healing and mineralized tissue formation. The present study investigated whether HSCs such as mineral trioxide aggregate (MTA) affect their biological and antimicrobial properties when used as long-term pulp protection materials. The effect of variables on treatment outcomes of three HSCs (ProRoot MTA, OrthoMTA, and RetroMTA) was evaluated clinically and radiographically over a 48–78 month follow-up period. Survival analysis was performed using Kaplan–Meier survival curves. Fisher’s exact test and Cox regression analysis were used to determine hazard ratios of clinical variables. The overall success rate of MTA partial pulpotomy was 89.3%; Cumulative success rates of the three HSCs were not statistically different when analyzed by Cox proportional hazard regression analysis. None of the investigated clinical variables affected success rates significantly. These HSCs showed favorable biocompatibility and antimicrobial properties in partial pulpotomy of permanent teeth in long-term follow-up, with no statistical differences between clinical factors.

Evaluation of the CERES-Rice Model for Precision Nitrogen Management for Rice in Northeast China

2017 ◽  
Vol 8 (2) ◽  
pp. 328-332
Author(s):  
J. Zhang ◽  
Y. Miao ◽  
W.D. Batchelor
Keyword(s):  
Northeast China ◽  
Weather Data ◽  
Cool Season ◽  
Use Efficiency ◽  
Optimum N Rate ◽  
Management Recommendations ◽  
N Management ◽  
N Rates ◽  
N Use

Over-application of nitrogen (N) in rice (Oryza sativaL.) production in China is common, leading to low N use efficiency (NUE) and high environmental risks. The objective of this work was to evaluate the ability of the CERES-Rice crop growth model to simulate N response in the cool climate of Northeast China, with the long term goal of using the model to develop optimum N management recommendations. Nitrogen experiments were conducted from 2011–2015 in Jiansanjiang, Heilongjiang Province in Northeast China. The CERES-Rice model was calibrated for 2014 and 2015 and evaluated for 2011 and 2013 experiments. Overall, the model gave good estimations of yield across N rates for the calibration years (R2=0.89) and evaluation years (R2=0.73). The calibrated model was then run using weather data from 2001–2015 for 20 different N rates to determine the N rate that maximized the long term marginal net return (MNR) for different N prices. The model results indicated that the optimum mean N rate was 120–130 kg N ha–1, but that the simulated optimum N rate varied each year, ranging from 100 to 200 kg N ha–1. Results of this study indicated that the CERES-Rice model was able to simulate cool season rice growth and provide estimates of optimum regional N rates that were consistent with field observations for the area.

scholarly journals Epichloë Endophyte Infection Rates and Alkaloid Content in Commercially Available Grass Seed Mixtures in Europe

2020 ◽  
Vol 8 (4) ◽  
pp. 498
Author(s):  
Jochen Krauss ◽  
Veronika Vikuk ◽  
Carolyn A. Young ◽  
Markus Krischke ◽  
Martin J. Mueller ◽  
...  
Keyword(s):  
Fungal Endophytes ◽  
Grass Species ◽  
Infection Status ◽  
Infection Rates ◽  
Cool Season ◽  
Infected Seed ◽  
Toxic Alkaloids ◽  
Cool Season Grass ◽  
Epichloë Endophyte ◽  
Seed Mixtures

Fungal endophytes of the genus Epichloë live symbiotically in cool season grass species and can produce alkaloids toxic to insects and vertebrates, yet reports of intoxication of grazing animals have been rare in Europe in contrast to overseas. However, due to the beneficial resistance traits observed in Epichloë infected grasses, the inclusion of Epichloë in seed mixtures might become increasingly advantageous. Despite the toxicity of fungal alkaloids, European seed mixtures are rarely tested for Epichloë infection and their infection status is unknown for consumers. In this study, we tested 24 commercially available seed mixtures for their infection rates with Epichloë endophytes and measured the concentrations of the alkaloids ergovaline, lolitrem B, paxilline, and peramine. We detected Epichloë infections in six seed mixtures, and four contained vertebrate and insect toxic alkaloids typical for Epichloë festucae var. lolii infecting Lolium perenne. As Epichloë infected seed mixtures can harm livestock, when infected grasses become dominant in the seeded grasslands, we recommend seed producers to test and communicate Epichloë infection status or avoiding Epichloë infected seed mixtures.

scholarly journals Diversity and evolution of surface polysaccharide synthesis loci in Enterobacteriales

2019 ◽  
Author(s):  
Kathryn E. Holt ◽  
Florent Lassalle ◽  
Kelly L. Wyres ◽  
Ryan Wick ◽  
Rafal J. Mostowy
Keyword(s):  
Evolutionary Dynamics ◽  
Bacterial Species ◽  
Purifying Selection ◽  
Evolutionary Forces ◽  
Polysaccharide Synthesis ◽  
Surface Polysaccharides ◽  
Surface Polysaccharide ◽  
Selective Preservation ◽  
Multiple Species

Bacterial capsules and lipopolysaccharides are diverse surface polysaccharides (SPs) that serve as the frontline for interactions with the outside world. While SPs can evolve rapidly, their diversity and evolutionary dynamics across different taxonomic scales has not been investigated in detail. Here, we focused on the bacterial order Enterobacteriales (including the medically-relevant Enterobacteriaceae), to carry out comparative genomics of two SP locus synthesis regions, cps and kps, using 27,334 genomes from 45 genera. We identified high-quality cps loci in 22 genera and kps in 11 genera, around 4% of which were detected in multiple species. We found SP loci to be highly dynamic genetic entities: their evolution was driven by high rates of horizontal gene transfer (HGT), both of whole loci and component genes, and relaxed purifying selection, yielding large repertoires of SP diversity. In spite of that, we found the presence of (near-)identical locus structures in distant taxonomic backgrounds that could not be explained by recent exchange, pointing to long-term selective preservation of locus structures in some populations. Our results reveal differences in evolutionary dynamics driving SP diversity within different bacterial species, with lineages of Escherichia coli, Enterobacter hormachei and Klebsiella aerogenes most likely to share SP loci via recent exchange; and lineages of Salmonella enterica, Citrobacter sakazakii and Serratia marcescens most likely to share SP loci via other mechanisms such as long-term preservation. Overall, the evolution of SP loci in Enterobacteriales is driven by a range of evolutionary forces and their dynamics and relative importance varies between different species.

scholarly journals Drivers of Foliar Fungal Endophytic Communities of Kudzu (Pueraria montana var. lobata) in the Southeast United States

Diversity ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 185
Author(s):  
Maryam Shahrtash ◽  
Shawn P. Brown
Keyword(s):  
United States ◽  
Plant Pathogens ◽  
Invasive Plant ◽  
Fungal Endophytes ◽  
Management Strategies ◽  
Environmental Parameters ◽  
Plant Management ◽  
Host Genotype ◽  
Southeast United States ◽  
Pueraria Montana

Fungal endophytes play important roles in plant fitness and plant–microbe interactions. Kudzu (Pueraria montana var. lobata) is a dominant, abundant, and highly aggressive invasive plant in the Southeast United States. Kudzu serves as a pathogen reservoir that impacts economically important leguminous crops. We conducted the first investigations on kudzu fungal endophytes (Illumina MiSeq—ITS2) to elucidate drivers of endophytic communities across the heart of the invasive range in the Southeast United States (TN, MS, AL, GA). We tested the impacts of multiple environmental parameters (Chlorophyll, NO3−, K+, soil pH, leaf area, host genotype, traffic intensity, and geographic location) on foliar endophyte communities. Endophytic communities were diverse and structured by many factors in our PerMANOVA analyses, but location, genotype, and traffic (proxy for pollution) were the strongest drivers of community composition (R2 = 0.152, p < 0.001, R2 = 0.129, p < 0.001, and R2 = 0.126, p < 0.001, respectively). Further, we examined the putative ecological interactions between endophytic fungi and plant pathogens. We identify numerous OTUs that are positively and strongly associated with pathogen occurrence, largely within the families Montagnulaceae and Tremellales incertae sedis. Taken together, these data suggest location, host genetics and local pollution play instrumental roles in structuring communities, and integrative plant management must consider these factors when developing management strategies.

Long-Term Persistence of Cool-Season Grasses Planted to Suppress Broom Snakeweed, Downy Brome, and Weedy Forbs

2019 ◽  
Vol 72 (2) ◽  
pp. 266-274 ◽  
Author(s):  
Clinton A. Stonecipher ◽  
Eric Thacker ◽  
Kevin D. Welch ◽  
Michael H. Ralphs ◽  
Thomas A. Monaco
Keyword(s):  
Downy Brome ◽  
Cool Season

Control of Downy Brome (Bromus tectorum) with Herbicides and Perennial Grass Competition

1998 ◽  
Vol 12 (2) ◽  
pp. 391-396 ◽  
Author(s):  
Tom D. Whitson ◽  
David W. Koch
Keyword(s):  
Dry Matter ◽  
Perennial Grass ◽  
Integrated Approach ◽  
Growth Stages ◽  
Downy Brome ◽  
Cool Season ◽  
Growing Seasons ◽  
Annual Grasses ◽  
Russian Wildrye

Long-term control of downy brome with an integrated approach is needed in order to sustain range productivity. Studies were conducted to study the effectiveness of a combination of downy brome control practices. In two studies, glyphosate and paraquat were evaluated at various rates for up to three successive years for control of downy brome in rangeland. A third study evaluated the competitiveness of perennial cool-season grasses against downy brome in the absence of herbicides. Glyphosate, at 0.55 kg/ha, and 0.6 kg/ha paraquat provided selective downy brome control on rangeland when applications were combined with intensive grazing. Downy brome control was greater than 90% following two sequential years of 0.6 kg/ha paraquat at either the two- to eight-leaf stage or bloom stage at both study locations. At one study location, 0.55 kg/ha glyphosate provided 97% control after the first application at both growth stages. In the second study, control averaged greater than 92% following three sequential applications of glyphosate. When perennial cool-season grasses were seeded in the spring following fall tillage (no herbicides) and allowed to establish for three growing seasons, three of the five species were effective in reducing the reestablishment of downy brome. ‘Luna’ pubescent wheatgrass, ‘Hycrest’ crested wheatgrass, ‘Sodar’ streambank wheatgrass, ‘Bozoisky’ Russian wildrye, and ‘Critana’ thickspike wheatgrass controlled 100, 91, 85, 45, and 32% of the downy brome, respectively. Yields of perennial grass dry matter were 1,714, 1,596, 1,135, 900, and 792 kg/ha. Replacing noncompetitive annual grasses with competitive cool-season perennials will provide a longer term solution to a downy brome problem than the use of herbicides alone or with intensive grazing.

scholarly journals Immobilisation of living coral embryos and larvae

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Carly J. Randall ◽  
Christine Giuliano ◽  
David Mead ◽  
Andrew J. Heyward ◽  
Andrew P. Negri
Keyword(s):  
Early Life ◽  
Early Life History ◽  
Living Cells ◽  
Living Coral ◽  
Broadcast Spawning ◽  
Life History Stages ◽  
Gelling Temperature ◽  
Commercial Applications ◽  
Multiple Species

Abstract Embedding and immobilisation of living cells and microorganisms is used in a variety of research and commercial applications. Here we report the successful extended immobilisation of coral larvae in a low-gelling temperature agarose. Embryos and larvae of five broadcast-spawning Scleractinian species were immobilised in agarose gel and tested in a series of exploratory survival and settlement assays. The optimal developmental stage for immobilisation was after ciliation at approximately 24 hours post-fertilisation, after which, survival of immobilised larvae of all species was nearly 100%. In long-term assays, 50% of Montipora digitata larvae survived immobilised for 89 days. Furthermore, immobilised larvae of multiple species, that were released from the agarose, generally remained capable of settlement. These results demonstrate that the immobilisation of the early life-history stages of corals is possible for a variety of applications in basic and applied science.

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