Comparative biochemistry of the phytopathogenic fungus Helminthosporium. XVI. The production of victoxinine by H. sativum and H. victoriae

1976 ◽  
Vol 54 (9) ◽  
pp. 783-787 ◽  
Author(s):  
RossB. Pringle
Keyword(s):  
Phytopathogenic Fungi ◽  
Phytopathogenic Fungus ◽  
Toxic Metabolite ◽  
Comparative Biochemistry ◽  
Unique Product ◽  
Culture Filtrates ◽  
Close Relationship ◽  
Helminthosporium Victoriae

The toxic metabolite victoxinine (C17H29NO), considered previously to be a unique product of Helminthosporium victoriae, has been found consistently in culture filtrates of H. sativum strains isolated from a wide variety of sources. This indicates a close relationship between the two phytopathogenic fungi and adds another toxin to be considered in the etiology of diseases incited by H. sativum.

Role of toxins in etiology of root rot disease of wheat

1977 ◽  
Vol 55 (13) ◽  
pp. 1801-1806 ◽  
Author(s):  
Ross B. Pringle
Keyword(s):  
Root Rot ◽  
Toxic Substance ◽  
Toxic Metabolite ◽  
Root Rot Disease ◽  
Culture Filtrates ◽  
Helminthosporium Sativum ◽  
Rot Disease

Although no host-specific toxin, nor a great quantity of any toxic substance, has been found in culture filtrates of 26 different isolates of Helminthosporium sativum, the amount of the toxic metabolite, victoxinine, produced by these strains, may be correlated generally to their aggressiveness towards wheat.

scholarly journals The Methylcitrate Cycle is Required for Development and Virulence in the Rice Blast Fungus Pyricularia oryzae

2019 ◽  
Vol 32 (9) ◽  
pp. 1148-1161 ◽  
Author(s):  
Yuxin Yan ◽  
Huan Wang ◽  
Siyi Zhu ◽  
Jing Wang ◽  
Xiaohong Liu ◽  
...  
Keyword(s):  
Isocitrate Lyase ◽  
Glyoxylate Cycle ◽  
Single Gene ◽  
Fungal Growth ◽  
Pyricularia Oryzae ◽  
Blast Disease ◽  
Phytopathogenic Fungus ◽  
Complete Medium ◽  
Toxic Metabolite ◽  
Oxide Content

The methylcitrate cycle metabolizes propionyl-CoA, a toxic metabolite, into pyruvate. Pyricularia oryzae (syn. Magnaporthe oryzae) is a phytopathogenic fungus that causes a destructive blast disease in rice and wheat. We characterized the essential roles of the methylcitrate cycle in the development and virulence of P. oryzae using functional genomics. In P. oryzae, the transcript levels of MCS1 and MCL1, which encode a 2-methylcitrate synthase and a 2-methylisocitrate lyase, respectively, were upregulated during appressorium formation and when grown on propionyl-CoA-producing carbon sources. We found that deletion of MCS1 and MCL1 inhibited fungal growth on media containing both glucose and propionate, and media using propionate or propionyl-CoA-producing amino acids (valine, isoleucine, methionine, and threonine) as the sole carbon or nitrogen sources. The Δmcs1 mutant formed sparse aerial hyphae and did not produce conidia on complete medium (CM), while the Δmcl1 mutant showed decreased conidiation. The aerial mycelium of Δmcs1 displayed a lowered NAD+/NADH ratio, reduced nitric oxide content, and downregulated transcription of hydrophobin genes. Δmcl1 showed reduced appressorium turgor, severely delayed plant penetration, and weakened virulence. Addition of acetate recovered the growth of the wild type and Δmcs1 on medium containing both glucose and propionate and recovered the conidiation of both Δmcs1 and Δmcl1 on CM by reducing propionyl-CoA formation. Deletion of MCL1 together with ICL1, an isocitrate lyase gene in the glyoxylate cycle, greatly reduced the mutant’s virulence as compared with the single-gene deletion mutants (Δicl1 and Δmcl1). This experimental evidence provides important information about the role of the methylcitrate cycle in development and virulence of P. oryzae by detoxification of propionyl-CoA and 2-methylisocitrate.

scholarly journals Stagonospora avenae Secretes Multiple Enzymes that Hydrolyze Oat Leaf Saponins

2000 ◽  
Vol 13 (10) ◽  
pp. 1041-1052 ◽  
Author(s):  
John P. Morrissey ◽  
Jos P. Wubben ◽  
Anne E. Osbourn
Keyword(s):  
Antifungal Activity ◽  
Leaf Tissue ◽  
Phytopathogenic Fungi ◽  
Comprehensive Analysis ◽  
Gaeumannomyces Graminis ◽  
Phytopathogenic Fungus ◽  
Gene Encoding ◽  
Sugar Chain ◽  
Hydrolyzing Enzymes ◽  
Hydrolysis Of

The phytopathogenic fungus Stagonospora avenae is able to infect oat leaves despite the presence of avenacoside saponins in the leaf tissue. In response to pathogen attack, avenacosides are converted into 26-desglucoavenacosides (26-DGAs), which possess antifungal activity. These molecules are comprised of a steroidal backbone linked to a branched sugar chain consisting of one α-L-rhamnose and two (avenacoside A) or three (avenacoside B) β-D-glucose residues. Isolates of the fungus that are pathogenic to oats are capable of sequential hydrolysis of the sugar residues from the 26-DGAs. Degradation is initiated by removal of the L-rhamnose, which abolishes antifungal activity. The D-glucose residues are then hydrolyzed by β-glucosidase activity. A comprehensive analysis of saponin-hydrolyzing activities was undertaken, and it was established that S. avenae isolate WAC1293 secretes three enzymes, one α-rhamnosidase and two β-glucosidases, that carry out this hydrolysis. The major β-glucosidase was purified and the gene encoding the enzyme cloned. The protein is similar to saponin-hydrolyzing enzymes produced by three other phytopathogenic fungi, Gaeumannomyces graminis, Septoria lycopersici, and Botrytis cinerea, and is a family 3 β-glucosidase. The gene encoding the β-glucosidase is expressed during infection of oat leaves but is not essential for pathogenicity.

GENETICS OF PHYTOPATHOGENIC FUNGI: PECTOLYTIC ENZYMES OF VIRULENT AND AVIRULENT STRAINS OF THREE PHYTOPATHOGENIC PENICILLIA

1966 ◽  
Vol 44 (12) ◽  
pp. 1645-1650 ◽  
Author(s):  
E. D. Garber ◽  
L. Beraha
Keyword(s):  
Organic Carbon ◽  
Pectin Methylesterase ◽  
Defined Medium ◽  
Relative Activity ◽  
Phytopathogenic Fungi ◽  
Avirulent Strain ◽  
Culture Filtrates ◽  
Pectolytic Enzymes ◽  
Lyase Activity ◽  
Starch Gel

Culture filtrates from a virulent and an avirulent strain of each of three phytopathogenic species of Penicillium grown in a defined medium to which were added different sources of organic carbon had endopolygalacturonase (endoPG) and exopolygalacturonase (exoPG), but neither detectable pectin methylesterase nor pectin lyase activity. Extracts from diseased tissue of oranges inoculated with P. italicum or P. digitatum and from diseased tissue of apples inoculated with P. expansum, but not from healthy fruits, had endoPG and exoPG activity. Culture filtrates and extracts of diseased tissue were subjected to vertical starch-gel zone electrophoresis. The number, location (anodic, cathodic), electrophoretic mobility, and relative activity of sites of endoPG or exoPG activity were determined by the species, virulence or avirulence of the strain, source of organic carbon, and gel pH.

PHOMIC ACID: A TOXIC METABOLITE FROM PHOMA MEDICAGINIS MALBR. AND ROUM.

1967 ◽  
Vol 45 (6) ◽  
pp. 847-853 ◽  
Author(s):  
M. Lakshmanan ◽  
T. C. Vanterpool
Keyword(s):  
Ion Exchange ◽  
Leaf Spot ◽  
Leaf Spot Disease ◽  
Toxic Metabolite ◽  
Rape Seed ◽  
Spot Disease ◽  
Culture Filtrates ◽  
Phoma Medicaginis ◽  
Ascochyta Pisi

A crystalline toxic metabolite was isolated from culture filtrates of Phoma medicaginis, the fungus causing the black stem and leaf spot disease of alfalfa. Ion exchange methods employed for its isolation are presented. It inhibits the germination of flax and rape seed, melts at 259–260 °C, and has absorption peaks at 208 and 260 mμ. in water. It differs markedly from ascochytine isolated earlier from cultures of Ascochyta pisi and A. fabae. The name 'phomic acid' is suggested for the toxin.

scholarly journals Characterization of sirodesmins isolated from the phytopathogenic fungus Leptosphaeria maculans

2012 ◽  
Vol 77 (10) ◽  
pp. 1363-1379 ◽  
Author(s):  
Petar Mitrovic ◽  
Dejan Orcic ◽  
Zvonimir Sakac ◽  
Ana Marjanovic-Jeromela ◽  
Nada Grahovac ◽  
...  
Keyword(s):  
High Performance ◽  
Chemical Nature ◽  
Leptosphaeria Maculans ◽  
Stem Canker ◽  
Phytopathogenic Fungi ◽  
Phytopathogenic Fungus ◽  
Brassica Napus L ◽  
Layer Chromatography ◽  
Detailed Chemical

Pathogenicity of phytopathogenic fungi is accociated with phytotoxins, especially with their chemical nature and quantity. Sirodesmins are phytotoxins from epipolythiodioxopiperazines group, produced by fungi Leptosphaeria maculans that is a cause of blackleg and stem canker in oilseed rape (Brassica napus L.). The aim of this work was to obtain a detailed chemical profile of sirodesmins in five fungal isolates (four from Vojvodina and one from UK). Sirodesmins showing different phytotoxicity on treated cotyledons of cv. Quinta were separated and detected by thin layer chromatography in all analysed isolates (L.m, C-3, St-5, S-11) except K-113, which did not contain sirodesmin congeners nor exhibited activity. By use of high performance liquid chromatography coupled with tandem mass spectrometer, it was possible to identify total of 10 sirodesmins, together with their precursor - phomamide. It was found that dominant epipolythiodioxopiperazines of investigated L. maculans isolates were sirodesmin PL, sirodesmin C, and their deacetylated derivatives.

scholarly journals Complete Genome Sequence of the First Chrysovirus From the Phytopathogenic Fungus Alternaria Solani on Potato in China

2021 ◽  
Author(s):  
Chenghui Hu ◽  
Siwei Li ◽  
Chunyan Wu ◽  
Yiran Mi ◽  
Qingnian Cai ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Alternaria Solani ◽  
Untranslated Regions ◽  
Phytopathogenic Fungus ◽  
Full Genome ◽  
Double Stranded Rna ◽  
The Family ◽  
Helminthosporium Victoriae ◽  
Dsrna Mycovirus ◽  
A New Species

Abstract The full genome of a double-stranded RNA (dsRNA) mycovirus, which was isolated from Alternaria solani strain DT-10 causing potato foliar disease and designated as Alternaria solani chrysovirus 1 (AsCV1), consisted of four dsRNA segments (dsRNA 1–4) with the length of 3600 bp, 3128 bp, 2996 bp, and 2714 bp, respectively. RNA-dependent RNA polymerase (RdRp, 1084 amino acids (aa)), putative capsid protein (905 aa), Alphachryso-P3 (835 aa), and Alphachryso-P4 (729 aa) were encoded by dsRNA1, dsRNA2, dsRNA3, and dsRNA4, respectively, which had the highest identities of 41.77%-72.38% to the counterparts of Helminthosporium victoriae virus 145S (HvV145S) in the genus Alphachrysovirus of the family Chrysoviridae. Moreover, the 5′-untranslated regions (UTRs) with several unique inserts (3–37 bp) and deletions (5–64 bp) of AsCV1 dsRNA 1–4 shared 51.65%-68.01% identities to those of HvV145S. Phylogenetic analysis of RdRp suggested that AsCV1 clustered the most closely with HvV145S. Based on the characteristics of distinct host, low identities of encoded proteins, special traits in 5′-UTRs of dsRNA 1–4, and phylogenetic analysis of RdRp, AsCV1 was confirmed to be a new species in the genus Alphachrysovirus. To our best knowledge, this is the first alphachrysovirus identified from phytopathogenic A. solani.

scholarly journals Enhanced Yield of Pepper Plants Promoted by Soil Application of Volatiles From Cell-Free Fungal Culture Filtrates Is Associated With Activation of the Beneficial Soil Microbiota

2021 ◽  
Vol 12 ◽  
Author(s):  
Edurne Baroja-Fernández ◽  
Goizeder Almagro ◽  
Ángela María Sánchez-López ◽  
Abdellatif Bahaji ◽  
Samuel Gámez-Arcas ◽  
...  
Keyword(s):  
Terrestrial Ecosystem ◽  
Amplicon Sequencing ◽  
Phytopathogenic Fungi ◽  
Growth And Yield ◽  
Rrna Genes ◽  
Fungal Culture ◽  
Soil Microbiota ◽  
Soil Application ◽  
Culture Filtrates ◽  
Nutritional Characteristics

Plants communicate with microorganisms by exchanging chemical signals throughout the phytosphere. Such interactions are important not only for plant productivity and fitness, but also for terrestrial ecosystem functioning. It is known that beneficial microorganisms emit diffusible substances including volatile organic compounds (VOCs) that promote growth. Consistently, soil application of cell-free culture filtrates (CF) of beneficial soil and plant-associated microorganisms enhances plant growth and yield. However, how this treatment acts in plants and whether it alters the resident soil microbiota, are largely unknown. In this work we characterized the responses of pepper (Capsicum annuum L.) plants cultured under both greenhouse and open field conditions and of soil microbiota to soil application of CFs of beneficial and phytopathogenic fungi. To evaluate the contribution of VOCs occurring in the CFs to these responses, we characterized the responses of plants and of soil microbiota to application of distillates (DE) of the fungal CFs. CFs and their respective DEs contained the same potentially biogenic VOCs, and application of these extracts enhanced root growth and fruit yield, and altered the nutritional characteristics of fruits. High-throughput amplicon sequencing of bacterial 16S and fungal ITS rRNA genes of the soil microbiota revealed that the CF and DE treatments altered the microbial community compositions, and led to strong enrichment of the populations of the same beneficial bacterial and fungal taxa. Our findings show that CFs of both beneficial and phytopathogenic fungi can be used as biostimulants, and provide evidence that VOCs occurring in the fungal CFs act as mediators of the plants’ responses to soil application of fungal CFs through stimulation of the beneficial soil microbiota.

scholarly journals Early Secretory Pathway-Associated Proteins SsEmp24 and SsErv25 Are Involved in Morphogenesis and Pathogenicity in a Filamentous Phytopathogenic Fungus

mBio ◽  
2021 ◽  
Vol 12 (6) ◽  
Author(s):  
Chong Xie ◽  
Qingna Shang ◽  
Chenmi Mo ◽  
Yannong Xiao ◽  
Gaofeng Wang ◽  
...  
Keyword(s):  
Virulence Factors ◽  
Secretory Pathway ◽  
Hydrolytic Enzymes ◽  
Phytopathogenic Fungi ◽  
Secretion System ◽  
Fungal Diseases ◽  
Phytopathogenic Fungus ◽  
Host Interactions ◽  
Early Secretory Pathway ◽  
Associated Proteins

Understanding the reproduction and pathogenesis mechanism of phytopathogens could provide new opinions to effectively control fungal diseases. Although it has been known that effectors and extracellular hydrolytic enzymes secreted by phytopathogenic fungi play important roles in fungus-host interactions, the secretion system for the delivery of virulence factors to the host is still largely undescribed.

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