Locoweed dose responses to nitrogen: Positive for biomass and primary physiology, but inconsistent for an alkaloid

Delaney, Kevin J.; Klypina, Nina; Maruthavanan, Janakiraman; Lange, Carol Jeannine; Sterling, Tracy M.

doi:10.3732/ajb.1100133

Cited by 18 publications

(24 citation statements)

References 42 publications

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“…An alternative interpretation is that the improved nitrogen status of the host may have increased substrate availability for swainsonine production; however, no consistent differences in swainsonine concentrations were observed in locoweed plants, whether nitrogen deficient or adequate, when nitrogen was supplied through fertilizer (Delaney et al . ). Lastly, swainsonine concentrations were shown to increase slightly in response to water stress in some locoweed species but not others (Vallotton et al .…”

Section: Endophytes Of Locoweeds and Related Taxamentioning

confidence: 97%

Bioactive alkaloids in vertically transmitted fungal endophytes

2013

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Summary1. Plants form mutualistic symbioses with a variety of microorganisms including endophytic fungi that live inside the plant and cause no overt symptoms of infection. Some endophytic fungi form defensive mutualisms based on the production of bioactive metabolites that protect the plant from herbivores in exchange for a protected niche and nutrition from the host plant. Key elements of these symbioses are vertical transmission of the fungus through seed of the host plant, a narrow host range, and production of bioactive metabolites by the fungus. 2. Grasses frequently form symbioses with endophytic fungi belonging to the family Clavicipitaceae. These symbioses have been studied extensively because of their significant impacts on insect and mammalian herbivores. Many of the impacts are likely due to the production of four classes of bioactive alkaloids -ergot alkaloids, lolines, indole-diterpenes and peraminethat are distributed in different combinations among endophyte taxa. 3. Several legumes, including locoweeds, are associated with a toxic syndrome called locoism as a result of their accumulation of swainsonine. Species in two genera were recently found to contain previously undescribed endophytic fungi (Undifilum spp., family Pleosporaceae) that are the source of that toxin. The fungi are strictly vertically transmitted and have narrow host ranges. 4. Some plant species in the morning glory family (Convolvulaceae) also form symbioses with endophytic fungi of the Clavicipitaceae that produce ergot alkaloids and, perhaps in at least one case, lolines. Other species in this plant family form symbioses with undescribed fungi that produce swainsonine. The swainsonine-producing endophytes associated with the Convolvulaceae are distinct from the Undifilum spp. associated with locoweeds and the Clavicipitaceous fungi associated with Convolvulaceae. 5. In the establishment of vertically transmitted symbioses, fungi must have entered the symbiosis with traits that were immediately useful to the plant. Bioactive metabolites are likely candidates for such pre-adapted traits which were likely useful to the free-living fungi as well. With future research, vertically transmitted fungi from diverse clades with narrow host ranges and that produce bioactive compounds are likely to be found as important mutualists in additional plants.

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Section: Endophytes Of Locoweeds and Related Taxamentioning

confidence: 97%

Bioactive alkaloids in vertically transmitted fungal endophytes

2013

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“…al. 2010) or tested in greenhouses with large plants (Delaney et al 2011;Vallotton et al 2012;Klypina et al 2017).…”

Section: Discussionmentioning

confidence: 99%

Evidence for nonpathogenic relationships ofAlternariasectionUndifilumendophytes within three host locoweed plant species

Noor

Nava

Cooke

et al. 2018

Botany

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Locoweeds are legumes of the Astragalus and Oxytropis genera that live symbiotically with the fungal endosymbionts belonging to Alternaria section Undifilum. These endophytes produce the toxin swainsonine, which causes a neurological syndrome (locosim) when the plant is ingested by grazing animals. Here we characterize the growth of the endophytes within plant tissues using confocal and scanning electron microscopy (SEM) to define the physical relationship. Microscopy results revealed the endophyte distribution to be densely networked, with the mycelia aligned parallel to the long axis of the plant stem and with no pathology to plant cell walls, xylem, or phloem. The autofluorescent mycelia were located intercellulary in the pith of stems. Stereofluoroscope observations of Alternaria oxytropis, A. cinerea, and A. fulva in phytoagar showed that mycelial growth occurred at the tip of hyphae. The growth rate of A. cinerea was significantly faster than for A. oxytropis or A. fulva. All three species of endophytes grew significantly faster at 3 days age of culture and grew slowly or not at all after 20 or 30 days. Analyses of the growth of these fungi support the hypothesis that there is a nonpathogenic symbiosis between the fungal endophytes and their host plants.

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“…Major HSPS are involved in cell growth and differentiation (Mehlen et al, 1997), physiological and cytoprotective functions (Bukau and Horwich, 1998) and play an important role in the survival of extreme environmental conditions (Ulmasov et al, 1992). Functions of HSPS in U. oxytropis remain to be elucidated, but current research suggests that the fungus may help moderate plant response to drought, heat, and nutrient deficiencies (Delaney et al, 2011;Oldrup et al, 2010). Enolase is a major glucan-associated cell wall protein (Angiolella et al, 1996;Pitarch et al, 2002).…”

Section: Discussionmentioning

confidence: 99%

“…The fungus is hypothesized to exist in a mutualistic association with its locoweed host plant due to its conservation across Oxytropis species and geographical locations (Gardner et al, 2001;Ralphs et al, 2008;Yu et al, 2010). However, specifics about the fungus/plant interaction have proved difficult to determine, in part due to lack of genetic information about either the plant or the fungus (Cook et al, 2009a;Delaney et al, 2011). Knowledge of the genetics of the fungus is limited to a few regions such as ITS (internal transcribed sequence), gpd (glyceraldehyde phosphate dehydrogenase), and mtssu (mitochondrial small subunit) that have been used to taxonomically characterize the fungus (Braun et al, 2003;Pryor et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

Proteomic analysis of the endophytic fungus Undifilum oxytropis

Li¹

2012

Afr. J. Biotechnol.

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The filamentous Ascomycete fungus Undifilum oxytropis is an endophyte of locoweed plants of the genera Oxytropis that produces a toxic alkaloid swainsonine. Swainsonine, an alpha-mannosidase inhibitor causes a general toxicosis and neurological problems (locoism) when consumed by grazing animals. Swainsonine is also being assessed for its anti-cancer properties. While the ecology of U. oxytropis has been studied, little is known about the genetics and proteomics of any swainsonine-producing fungus. To help understand the proteins in U. oxytropis, the proteome of U. oxytropis was analyzed using 2-dimensional electrophoresis (2-DE). Proteins from U. oxytropis mycelia were extracted and separated by in-gel isoelectric focusing (IEF). The entire immobilized pH gradient (IPG) strip was cut into a set of gel sections and each gel section was digested with trypsin and then identified using liquid chromatography tandem mass spectrometry (LC-MS/MS). 2-DE maps were also developed for U. oxytropis to define its proteome. In the isoelectric point (pI) range of 3-11 and 10-250 kDa ranges, more than 450 spots were detected in 2-DE silver-stained gels, and 52 proteins were identified by LC-MS/MS. Most of the identified proteins were involved in energy production, oxidoreductase activity, carbohydrate metabolic process, amino acid and cellular ketone metabolic process. A large group of identified proteins were related to stress proteins and heat shock proteins. This work presents the first two-dimensional reference map of this alkaloid-producing fungus. Details of the proteome serve as a baseline for further study of this swainsonine-producing fungus and are essential for a reverse genetic analysis of the fungus.

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Locoweed dose responses to nitrogen: Positive for biomass and primary physiology, but inconsistent for an alkaloid

Cited by 18 publications

References 42 publications

Bioactive alkaloids in vertically transmitted fungal endophytes

Bioactive alkaloids in vertically transmitted fungal endophytes

Evidence for nonpathogenic relationships ofAlternariasectionUndifilumendophytes within three host locoweed plant species

Proteomic analysis of the endophytic fungus Undifilum oxytropis

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