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

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Malinowski D. P., Belesky D. P.

Acta Agrobotanica

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2019

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tom 72

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nr 2

Many cool-season grass species have evolved with asexual, nonsymptomatic fungal endophytes of the genus Epichloë (formerly Neotyphodium) 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.

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Grassland communities in the USA and expected trends associated with climate change

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Belesky D. P., Malinowski D. P.

Acta Agrobotanica

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2016

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tom 69

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nr 2

Grasslands, including managed grazinglands, represent one of the largest ecosystems on the planet. Managed grazinglands in particular tend to occupy marginal climatic and edaphic resource zones, thus exacerbating responses in net primary productivity relative to changes in system resources, including anthropogenic factors. Climate dynamism, as evident from the fossil record, appears to be a putative feature of our planet. Recent global trends in temperature and precipitation patterns seem to differ from long-term patterns and have been associated with human activities linked with increased greenhouse gas emissions; specifically CO2. Thus grasslands, with their diverse floristic components, and interaction with and dependence upon herbivores, have a remarkable ability to persist and sustain productivity in response to changing resource conditions. This resistance and resilience to change, including uncertain long-term weather conditions, establishes managed grasslands as an important means of protecting food security. We review responses of grassland communities across regions of the USA and consider the responses in productivity and system function with respect to climatic variation. Research is needed to identify plant resources and management technologies that strengthen our ability to capitalize upon physiological and anatomical features prevalent in grassland communities associated with varying growing conditions.

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Climate change and the future of our world – implications for plant phenology, physiology, plant communities, and crop management

100%

Denisow B., Malinowski D. P.

Acta Agrobotanica

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2016

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tom 69

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nr 2

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Solar radiation affects bloat potential of wheat forage

81%

Malinowski D. P., Pinchak W. E., Pitta D., Min B. R.

Acta Agrobotanica

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2018

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tom 71

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nr 4

Frothy bloat is a serious digestive disorder in cattle (Bos taurus L.) grazing winter wheat (Triticum aestivum L.) pastures in the Southern Great Plains of the USA. Wheat plant metabolism may be one of the factors involved in bloat occurrence. In a series of experiments conducted during 2004–2007, we evaluated the effects of solar radiation intensity (ambient, 100% vs. reduced, 25%), a short-time (24 h vs. 48 h) exposure to solar radiation, and forage allowance (high, 18 kg vs. low, 6 kg DM/100 kg body weight) on seasonal concentration of phenolic compounds and foam strength (a measure of bloat potential) of wheat forage ‘Cutter’. Reduced solar radiation decreased total phenolic concentration and increased foam strength when compared to ambient solar radiation. Forage allowance interacted with solar radiation and short-term exposure treatments in determining phenolic concentrations; however, the effects were inconsistent during and among growing seasons. Concentration of phenolic compounds responded rapidly to sudden changes in weather patterns (passing cold fronts) that were usually associated with significant decrease in solar radiation intensity and temperature. Solar radiation intensity was positively correlated with total phenolic concentration and explained 62% to 72% of the variation in total phenolic concentration. Correlation between temperature and total phenolic concentration varied among growing seasons and explained 9–17% of the variation in total phenolic concentration. Results suggest that phenolic concentration in wheat forage is correlated with solar radiation. The decrease in phenolic concentration and resulting increase of bloat potential are especially pronounced during sudden changes in weather patterns during winter.

Ograniczanie wyników

4 Acta Agrobotanica

4 Malinowski D. P.

2 Belesky D. P.

1 Denisow B.

1 Min B. R.

1 Pinchak W. E.

1 Pitta D.

1 2019

1 2018

2 2016

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

Grassland communities in the USA and expected trends associated with climate change

Climate change and the future of our world – implications for plant phenology, physiology, plant communities, and crop management

Solar radiation affects bloat potential of wheat forage