The Relationship Between Intensity of Oxidative Metabolism and Predominance of Agroclavine or Elymoclavine in Submerged Claviceps purpurea Cultures

Pažoutová, Sylvie; Flieger, Miroslav; Sajdl, P.; Řeháček, Z.; Taisinger, Jan; Bass, A E

doi:10.1021/np50014a014

Cited by 30 publications

(14 citation statements)

References 9 publications

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“…The decline in expression of the GUS gene, controlled by a heterologous constitutive promoter, is to be expected as the mycelium enters stationary phase. Stationary phase, triggered through changes in the environment such as nutrient limitation, pH changes, or the accumulation of waste products (27), is accompanied in fungi and other organisms by reduced protein synthesis, even though specific pathways, such as secondary metabolite pathways, might become more active (1,4,8,9,24,30,36,41,43,44). In other words, in culture N. lolii biomass increase, through hyphal apical extension, and metabolic activity are correlated and linked.…”

Section: Discussionmentioning

confidence: 99%

In Planta Regulation of Extension of an Endophytic Fungus and Maintenance of High Metabolic Rates in Its Mycelium in the Absence of Apical Extension

Tan¹,

Spiering²,

Scott³

et al. 2001

Appl Environ Microbiol

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The fungus Neotyphodium lolii is an endophytic symbiont. It grows in the intercellular spaces of the perennial ryegrass Lolium perenne, producing secondary metabolites which enhance the fitness of the association over that of uninfected L. perenne. We report that the average number of hyphal strands in a given section of a leaf remains constant during the life of a leaf, indicating synchrony of leaf and hyphal extension, including cessation of hyphal extension when leaf extension ceases. We used a constitutively expressed reporter gene as an indicator of the mycelium's metabolic activity during and after hyphal extension. Reporter gene activity decreased when the mycelium stopped extending in liquid culture but not in planta. This indicates that in planta endophyte hyphae remain metabolically highly active when extension has ceased and throughout the life of the leaf they are colonizing. The behavior of the fungus in planta indicates the existence of signaling pathways which (i) synchronize the extension of leaf and hypha by regulating hyphal extension, (ii) suppress hyphal branching, and (iii) stop apical extension of fungal hyphae, without reducing the mycelium's metabolic activity. These signals may be crucial for the symbiosis, by allowing the endophyte to switch the focus of its metabolic activity from extension to the production of secondary metabolites.Neotyphodium endophytes are mutualistic symbionts of grasses, living in their intercellular spaces. Their presence confers upon the grass a number of physiological characteristics such as drought resistance, enhanced growth, and protection from herbivores, through the synthesis of feeding deterrents and toxins. In return, the plant provides nutrients and propagates the endophyte via its seeds (17,28,34,35,46,47).We have recently used a Neotyphodium endophyte, transformed with the Escherichia coli ␤-glucuronidase gene (GUS reporter gene system [14]), under the control of a heterologous constitutive promoter, to estimate the in planta distribution of endophyte metabolic activity (as GUS activity) (12). We found that GUS activity followed well-defined patterns, established during the growth of ryegrass leaves (12). The endophyte metabolic activity in plant tissue measured in such experiments depends on (i) the number of endophyte hyphae present, (ii) the rate of gene expression in these hyphae, and (iii) the half-life of the GUS enzyme. Thus, while the existence of these patterns was intriguing, these experiment allowed only limited conclusions as to how they are generated. We have now determined directly the in planta distribution of endophyte hyphal biomass. In parallel, we have determined the endophyte's constitutive GUS expression in the same ryegrass tillers. We have also determined GUS activity in exponentially growing and stationary laboratory cultures of the same endophyte strain. Together, these data allow us to draw conclusions regarding the endophyte's metabolic state in different parts of the ryegrass tiller. MATERIALS AND METHODSStrains and plant ...

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Section: Discussionmentioning

confidence: 99%

In Planta Regulation of Extension of an Endophytic Fungus and Maintenance of High Metabolic Rates in Its Mycelium in the Absence of Apical Extension

Tan¹,

Spiering²,

Scott³

et al. 2001

Appl Environ Microbiol

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“…American isolates were col- Isolates were obtained from honeydew drops present on the specimens that were plated on sucrose-asparagine medium T2 (Pañoutová et al 1981). Each isolate was prepared from a different floret.…”

Section: Methodsmentioning

confidence: 99%

Ergot fungusClaviceps cynodontisfound on Bermuda grass (Cynodon dactylon) in the Americas

Pažoutová

Odvody

Frederickson

2005

Canadian Journal of Plant Pathology

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Claviceps cynodontis is a widespread parasite of Cynodon spp. (Bermuda grass) in the paleotropical and subtropical regions. The sphacelial stage of ergot on Cynodon dactylon in México and Texas was identified as that of Claviceps cynodontis by comparison of conidial morphology, rDNA sequence, and random amplified polymorphic DNA (RAPD) patterns with an African isolate of this species. Sequence of internal transcribed spacers ITS1-5.8S-ITS2 of Claviceps cynodontis clustered phylogenetically with those of Claviceps maximensis, Claviceps rhynchelytri, and Claviceps sp. SG (from Setaria geniculata). This is the first record of the identification of Claviceps cynodontis in the Americas.Résumé : Le Claviceps cynodontis est un parasite des Cynodon spp. (chiendent pied-de-poule) très répandu dans les régions paléotropicales et subtropicales. Le stade sphacelium de l'ergot sur le Cynodon dactylon au Mexique et au Texas a été identifié comme appartenant au Claviceps cynodontis après comparaison de la morphologie des conidies, de la séquence de l'ADNr et de profils d'ADN polymorphe amplifié au hasard avec un isolat africain de cette espèce. La séquence de l'espaceur transcrit interne ITS1-5.8S-ITS2 du Claviceps cynodontis se regroupait phylogénétiquement avec celles du Claviceps maximensis, du Claviceps rhynchelytri et de la Claviceps sp. SG (du Setaria geniculata). Ce rapport est le premier sur l'identification du Claviceps cynodontis dans les Amériques.

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“…C. zizaniae CCM 8240 and CCM 8231 were collected in Canada (1996), isolated from sclerotia by Dr. L. Marvanová (Czech Collection of Microorganisms, Brno, Czech Republic), and maintained on T2 agar slants. 13 Submerged fermentation conditions were used (Pažoutová et al 14 ), and medium T2 consisted of (g/L) sucrose (100), asparagine (10) Extraction and Alkaloid Isolation. Fermentation broth (100 mL) was centrifuged for 10 min at 8000 rpm (10°C) and the pH of the supernatant adjusted to 9.0 with concentrated NH 4OH, and it was then extracted twice with 100 mL of CHCl3.…”

Section: Methodsmentioning

confidence: 99%

Ergot Alkaloids Produced by Submerged Cultures of Claviceps zizaniae

et al. 2002

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Two ergopeptine alkaloids, alpha-ergocryptine (1) and its C(8) epimer alpha-ergocryptinine, have been isolated from the mycelium and fermentation broth of submerged cultures of Claviceps zizaniae CCM 8240. The structure of 1 was determined by HPLC/positive ion APCI MS and NMR analysis. Alkaloid concentrations of 10 microg/mL in 14-day-old fermentation broth and 1 mg/g of dry mycelium mass were found. These results are of considerable biotechnological interest since these were the only detectable alkaloids produced. Toxicity of naturally occurring sclerotia of C. zizaniae cannot be excluded.

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The Relationship Between Intensity of Oxidative Metabolism and Predominance of Agroclavine or Elymoclavine in Submerged Claviceps purpurea Cultures

Cited by 30 publications

References 9 publications

In Planta Regulation of Extension of an Endophytic Fungus and Maintenance of High Metabolic Rates in Its Mycelium in the Absence of Apical Extension

In Planta Regulation of Extension of an Endophytic Fungus and Maintenance of High Metabolic Rates in Its Mycelium in the Absence of Apical Extension

Ergot fungusClaviceps cynodontisfound on Bermuda grass (Cynodon dactylon) in the Americas

Ergot Alkaloids Produced by Submerged Cultures of Claviceps zizaniae

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