Accumulation and Biosynthesis of Solanapyrone Phytotoxins by Ascochyta rabiei

1995 ◽  
Vol 50 (3-4) ◽  
pp. 181-185
Author(s):  
Gregor Benning ◽  
Wolfgang Barz
Keyword(s):  
Stationary Phase ◽  
Secondary Metabolism ◽  
Carbon Skeleton ◽  
Labelling Pattern ◽  
Ascochyta Rabiei ◽  
Phytopathogenic Fungus ◽  
Typical Pattern ◽  
Accumulation Kinetics ◽  
Tracer Experiments

The biosynthesis of the phytotoxins solanapyrone A , B and C produced by the phytopathogenic fungus Ascochyta rabiei has been investigated. To optimize feeding conditons for the tracer experiments the growth of the fungus and the accumulation of the toxins in submers culture were determined. The accumulation kinetics revealed that formation of the toxins occurs in the stationary phase of the growth indicating that synthesis of solanapyrones follows a typical pattern of secondary metabolism. Incorporation experiments with sodium [1-14C]- and [2-13C]acetate were performed and the NMR-spectroscopically determined labelling pattern of the 13C-enriched solanapyrone A compound confirmed that the carbon skeleton of this compound is formed via the polyketide pathway. The biosynthetic route to solanapyrone B is discussed.

Karyotype polymorphism and chromosomal rearrangement in populations of the phytopathogenic fungus, Ascochyta rabiei

2012 ◽  
Vol 116 (11) ◽  
pp. 1119-1133 ◽  
Author(s):  
Hajime O. Akamatsu ◽  
Martin I. Chilvers ◽  
Walter J. Kaiser ◽  
Tobin L. Peever
Keyword(s):  
Chromosomal Rearrangement ◽  
Ascochyta Rabiei ◽  
Phytopathogenic Fungus ◽  
Karyotype Polymorphism

Physiological regulation of protease activity in Streptomyces peucetius

1988 ◽  
Vol 34 (2) ◽  
pp. 187-190 ◽  
Author(s):  
Gregory D. Gibb ◽  
William R. Strohl
Keyword(s):  
Stationary Phase ◽  
Secondary Metabolism ◽  
Proteolytic Activity ◽  
Protease Activity ◽  
Antineoplastic Agents ◽  
Defined Medium ◽  
Late Stationary Phase ◽  
Streptomyces Peucetius ◽  
Physiological Regulation ◽  
Cellular Turnover

Streptomyces peucetius ATCC 29050, a producer of anthracycline antineoplastic agents, was investigated for the expression of intracellular and extracellular azocaseinase activities as a function of growth and medium conditions. When cultures were grown in either nitrate-containing defined medium or glucose – yeast extract complex medium, the intracellular proteolytic activity was greatest during early to mid stationary phase, whereas the extracellular proteolytic activity was produced in late stationary phase. All of the proteolytic activity detected against azocasein was of a serine-type protease activity. These late-occurring proteases may have some function in cellular turnover associated with secondary metabolism and (or) morphogenesis.

scholarly journals Two Histone Deacetylases, FfHda1 and FfHda2, Are Important for Fusarium fujikuroi Secondary Metabolism and Virulence

2013 ◽  
Vol 79 (24) ◽  
pp. 7719-7734 ◽  
Author(s):  
L. Studt ◽  
F. J. Schmidt ◽  
L. Jahn ◽  
C. M. K. Sieber ◽  
L. R. Connolly ◽  
...  
Keyword(s):  
Secondary Metabolism ◽  
Secondary Metabolite ◽  
Filamentous Fungi ◽  
Histone Deacetylases ◽  
Control Plant ◽  
Gene Clusters ◽  
Phytopathogenic Fungus ◽  
Fusarium Fujikuroi ◽  
Content Type ◽  
Encoding Genes

ABSTRACTHistone modifications are crucial for the regulation of secondary metabolism in various filamentous fungi. Here we studied the involvement of histone deacetylases (HDACs) in secondary metabolism in the phytopathogenic fungusFusarium fujikuroi, a known producer of several secondary metabolites, including phytohormones, pigments, and mycotoxins. Deletion of three Zn2+-dependent HDAC-encoding genes,ffhda1,ffhda2, andffhda4, indicated that FfHda1 and FfHda2 regulate secondary metabolism, whereas FfHda4 is involved in developmental processes but is dispensable for secondary-metabolite production inF. fujikuroi. Single deletions offfhda1andffhda2resulted not only in an increase or decrease but also in derepression of metabolite biosynthesis under normally repressing conditions. Moreover, double deletion of both theffhda1andffhda2genes showed additive but also distinct phenotypes with regard to secondary-metabolite biosynthesis, and both genes are required for gibberellic acid (GA)-induced bakanae disease on the preferred host plant rice, as Δffhda1Δffhda2mutants resemble the uninfected control plant. Microarray analysis with a Δffhda1mutant that has lost the major HDAC revealed differential expression of secondary-metabolite gene clusters, which was subsequently verified by a combination of chemical and biological approaches. These results indicate that HDACs are involved not only in gene silencing but also in the activation of some genes. Chromatin immunoprecipitation with the Δffhda1mutant revealed significant alterations in the acetylation state of secondary-metabolite gene clusters compared to the wild type, thereby providing insights into the regulatory mechanism at the chromatin level. Altogether, manipulation of HDAC-encoding genes constitutes a powerful tool to control secondary metabolism in filamentous fungi.

The biosynthesis of antibiotic F-244 in Fusarium sp. ATCC 20788: origin of the carbon, hydrogen, and oxygen atoms

1995 ◽  
Vol 73 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Endang Saepudin ◽  
Paul Harrison
Keyword(s):  
Methyl Ester ◽  
Lactone Ring ◽  
Carbon Skeleton ◽  
Labelling Pattern ◽  
Nucleophilic Attack ◽  
Hydroxyl Group ◽  
Hydrogen Atoms ◽  
Isotope Shifts ◽  
Fusarium Sp ◽  
Oxygen Atoms

Biosynthetic incorporation experiments were performed with carbon-13 labelled precursors including sodium [1-13C]-, [2-13C], and [1,2-13C2]-acetate as well as [methyl-13C]methionine into antibiotic F-244 (1) in growing cultures of Fusarium sp. ATCC 20788. After conversion to the methyl ester 2, analysis by NMR showed that the carbon skeleton of 1 derives from seven intact acetate units; the remaining four carbons are from methionine. Hence, the pathway is similar to that reported for 1 in Scopulariopsis. The biogenesis of the hydrogen atoms in 1 was also investigated. Incorporation of sodium [1-13C, 18O2]acetate gives 2, which exhibits 18O-induced isotope shifts at C-1 and C-3. The labelling pattern is consistent with formation of the β-lactone ring by nucleophilic attack of a C-3 hydroxyl group in the nascent polyketide precursor onto the C-1 carbonyl. Keywords: biosynthesis, polyketide, F-244, β-lactone, Fusarium.

scholarly journals Light-Dependent Functions of the Fusarium fujikuroi CryD DASH Cryptochrome in Development and Secondary Metabolism

2013 ◽  
Vol 79 (8) ◽  
pp. 2777-2788 ◽  
Author(s):  
Marta Castrillo ◽  
Jorge García-Martínez ◽  
Javier Avalos
Keyword(s):  
Secondary Metabolism ◽  
Nitrogen Starvation ◽  
Phytopathogenic Fungus ◽  
Fusarium Fujikuroi ◽  
Mrna Levels ◽  
Wild Type ◽  
Gene Encoding ◽  
Content Type ◽  
Gibberellin Production ◽  
In The Wild

ABSTRACTDASH (Drosophila,Arabidopsis,Synechocystis, human) cryptochromes (cry-DASHs) constitute a subgroup of the photolyase cryptochrome family with diverse light-sensing roles, found in most taxonomical groups. The genome ofFusarium fujikuroi, a phytopathogenic fungus with a rich secondary metabolism, contains a gene encoding a putative cry-DASH, named CryD. The expression of thecryDgene is induced by light in the wild type, but not in mutants of the “white collar” genewcoA. Targeted ΔcryDmutants show light-dependent phenotypic alterations, including changes in morphology and pigmentation, which disappear upon reintroduction of a wild-typecryDallele. In addition to microconidia, the colonies of the ΔcryDmutants produced under illumination and nitrogen starvation large septated spores called macroconidia, absent in wild-type colonies. The ΔcryDmutants accumulated similar amounts of carotenoids to the control strain under constant illumination, but produced much larger amounts of bikaverin under nitrogen starvation, indicating a repressing role for CryD in this biosynthetic pathway. Additionally, a moderate photoinduction of gibberellin production was exhibited by the wild type but not by the ΔcryDmutants. The phenotypic alterations of the ΔcryDmutants were only noticeable in the light, as expected from the low expression ofcryDin the dark, but did not correlate with mRNA levels for structural genes of the bikaverin or gibberellin biosynthetic pathways, suggesting the participation of CryD in posttranscriptional regulatory mechanisms. This is the first report on the participation of a cry-DASH protein in the regulation of fungal secondary metabolism.

Morphological Characterization of Mycobacteriophage R1

1974 ◽  
Vol 32 ◽  
pp. 254-255
Author(s):  
B. L. Soloff ◽  
T. A. Rado
Keyword(s):  
Carbon Source ◽  
Stationary Phase ◽  
Growth Phase ◽  
Minimal Medium ◽  
Morphological Characterization ◽  
Logarithmic Growth Phase ◽  
Complete Lysis ◽  
Lysogenic Culture ◽  
Logarithmic Growth

Mycobacteriophage R1 was originally isolated from a lysogenic culture of M. butyricum. The virus was propagated on a leucine-requiring derivative of M. smegmatis, 607 leu−, isolated by nitrosoguanidine mutagenesis of typestrain ATCC 607. Growth was accomplished in a minimal medium containing glycerol and glucose as carbon source and enriched by the addition of 80 μg/ ml L-leucine. Bacteria in early logarithmic growth phase were infected with virus at a multiplicity of 5, and incubated with aeration for 8 hours. The partially lysed suspension was diluted 1:10 in growth medium and incubated for a further 8 hours. This permitted stationary phase cells to re-enter logarithmic growth and resulted in complete lysis of the culture.

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