Soil organic carbon fractions differ in two contrasting tall fescue systems

Handayani, Iin; Coyne, Mark S.; Phillips, Timothy D.

doi:10.1007/s11104-010-0352-z

Cited by 24 publications

(10 citation statements)

References 46 publications

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“…Carbon released from plant roots, depending on the chemical form, can be rapidly mineralized (0.5–2 h) by the rhizosphere microbial community, and/or incorporated into microbial biomass where it can persist for longer time periods (30–90 days) (Jones et al, 2004 ). Several studies have reported increases in C and N in pasture soils throughout the southeastern United States under CTE+ compared to E- infected tall fescue (Franzluebbers et al, 1999b ; Franzluebbers and Stuedemann, 2005 ; Iqbal et al, 2012 ), although in other studies the same trend was not observed (Handayani et al, 2011 ). If endophyte-associated changes to root exudation mediate the observed alterations to total C and N pools, the fact that we observed increased total C exudation in CTE+/97TF1 but not CTE+/PDF suggests that the conflicting reports may be related to different cultivars being examined.…”

Section: Discussionmentioning

confidence: 91%

Tall fescue cultivar and fungal endophyte combinations influence plant growth and root exudate composition

2015

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Tall fescue [Lolium arundinaceum (Schreb.)] is a cool-season perennial grass used in pastures throughout the Southeastern United States. The grass can harbor a shoot-specific fungal endophyte (Epichloë coenophiala) thought to provide the plant with enhanced resistance to biotic and abiotic stresses. Because alkaloids produced by the common variety of the endophyte cause severe animal health issues, focus has been on replacing the common-toxic strain with novel varieties that do not produce the mammal-toxic alkaloids but maintain abiotic and biotic stress tolerance benefits. Little attention has been given to the influence of the plant-fungal symbiosis on rhizosphere processes. Therefore, our objective was to study the influence of this relationship on plant biomass production and root exudate composition in tall fescue cultivars PDF and 97TF1, which were either not infected with the endophyte (E-), infected with the common toxic endophyte (CTE+) strain or with one of two novel endophytes (AR542E+, AR584E+). Plants were grown sterile for 3 weeks after which plant biomass, total organic carbon, total phenolic content and detailed chemical composition of root exudates were determined. Plant biomass production and exudate phenolic and organic carbon content were influenced by endophyte status, tall fescue cultivar, and their interaction. GC-TOF MS identified 132 compounds, including lipids, carbohydrates and carboxylic acids. Cluster analysis showed that the interaction between endophyte and cultivar resulted in unique exudate profiles. This is the first detailed study to assess how endophyte infection, notably with novel endophytes, and tall fescue cultivar interact to influence root exudate composition. Our results illustrate that tall fescue cultivar and endophyte status can influence plant growth and root exudate composition, which may help explain the observed influence of this symbiosis on rhizosphere biogeochemical processes.

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Section: Discussionmentioning

confidence: 91%

Tall fescue cultivar and fungal endophyte combinations influence plant growth and root exudate composition

2015

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“…When 8 to 15 year-old tall fescue pastures had high endophyte infection levels, potential C mineralization per unit of soil organic C was lower than when endophyte infection levels were low (Franzluebbers et al 1999). At the end of 4 years of seed-harvest management of tall fescue in Kentucky, potential C mineralization per unit of microbial biomass C was lower under E+ than under E− tall fescue (Handayani et al 2010). Leaf litter from E+ tall fescue decomposed slower than from E− tall fescue throughout a 24-week litter-bag study (Siegrist et al 2010).…”

mentioning

confidence: 92%

Soil microbial community function, structure, and glomalin in response to tall fescue endophyte infection

et al. 2010

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Tall fescue [Lolium arundinaceum (Schreb.) S.J. Darbyshire] is naturally infected with a fungal endophyte, Neotyphodium coenophialum, which produces toxic ergot alkaloids that negatively affect herbivores and may alter soil microbial communities. A 60-week mesocosm study with a factorial arrangement of soil type (clay loam and loamy sand) and endophyte infection (with and without) was conducted to determine changes in soil microbial community function (substrate utilization using Biolog), structure (phospholipid fatty acid profile), and glomalin concentration. Microbial utilization of carbohydrate, carboxylic acid, and miscellaneous substrate groups was lower in soil planted to endophyte-infected tall fescue than in soil planted to endophyte-free tall fescue. Gram-positive bacteria, arbuscular mycorrhizae, and glomalin in small (0.25-1.0 mm) and large (>1 mm) water-stable macro-aggregates were also negatively affected by endophyte infection. Although microbial changes due to endophyte infection were not ubiquitous and overwhelming, they were consistent with previous observations of reduced decomposition of endophyte-infected tall fescue plant litter, which may lead to greater soil C sequestration.

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“…Organic C Increased [149,153] Carbohydrates Increased [149] Phenols Increased [150] Organic Matter Increased [153] Microbial Biomass C Mixed Results [147,154] Mineralizable C Decreased [147,154] Microbial Biomass N Increased [147] Mineralizable N Increased was diseased with Verticillium, it was found that beneficial bacteria and fungi were greatly reduced and saprophytic fungi were increased [162]. Similarly, aphid infestation of the aerial parts of pepper plants led to root exudation composition changes to recruit bacteria that aided in aphid susceptibility [163].…”

Section: Soil Component E+ Effect Referencementioning

confidence: 98%

“…C sequestration is the ability of the soil to fix atmospheric C. This provides important environmental effects as well as providing an essential nutrient to the plant and soil microorganisms. Handayani et al [154] looked at C levels in the two tall fescue systems over the course of four years. They took data on microbial biomass, particulate organic matter C, microbial biomass C, mineralizable C, and C in micro and macro aggregates.…”

Section: Epichloe Effect On the Rhizospherementioning

confidence: 99%

Interaction Between Grasses and <em>Epichloe</em> Endophytes and Its Significance to Biotic and Abiotic Stress Tolerance and the Rhi-Zosphere

Lee¹,

Missaoui²,

Mahmud³

et al. 2021

Preprint

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Cool-season grasses are the most common forage types in livestock operations and amenities. Several of the cool-season grasses establish mutualistic associations with an endophytic fungus of the Epichloe genus. The grasses and endophytic fungi have evolved over a long period of time to form host-fungus specific relationships that confer protection for the grass against various stressors in exchange for housing and nutrients to the fungus. This review provides an overview of the mechanisms by which Epichloe endophytes and grasses interact, including molecular pathways for secondary metabolite production. It also outlines specific mechanisms by which the endophyte helps protect the plant from various abiotic and biotic stressors. Finally, the review provides information on how Epichloe infection of grass and stress affect the rhizosphere environment of the plant.

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Soil organic carbon fractions differ in two contrasting tall fescue systems

Cited by 24 publications

References 46 publications

Tall fescue cultivar and fungal endophyte combinations influence plant growth and root exudate composition

Tall fescue cultivar and fungal endophyte combinations influence plant growth and root exudate composition

Soil microbial community function, structure, and glomalin in response to tall fescue endophyte infection

Interaction Between Grasses and <em>Epichloe</em> Endophytes and Its Significance to Biotic and Abiotic Stress Tolerance and the Rhi-Zosphere

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