Effect of oxafun on the antibiosis between Bacillus subtilis and Phoma betae

The fungicide oxafun decreased the production of antibiotic substances active against Phoma betae, by Bacillus subtillis. This was confirmed by reduced effectiveness of antibiotic substances against Phoma infection in micropot experiment. Besides, the bacterial metabolites effected cell membrane permeability of mycelium and resulted in some relationships of fungicide and antibiotic substances.     

Systematic reappraisal of species in Phoma section Paraphoma, Pyrenochaeta and Pleurophoma

Sequence data from the 18S nrDNA (SSU) and 28S nrDNA (LSU) regions of isolates of Phoma section Paraphoma were compared with those of representative isolates of the morphologically similar anamorph genera Pleurophoma and Pyrenochaeta and of the type species of Phoma sections Phoma, Pilosa and Plenodomus. Phoma section Paraphoma was found to be highly polyphyletic within the Pleosporales and only distantly related to Phoma section Phoma. The genus Paraphoma, which is based on Paraphoma radicina, is reintroduced in the Phaeosphaeriaceae with two additional taxa. The new genera Setophoma and Neosetophoma, type species Setophoma terrestris comb. nov. and Neosetophoma samarorum comb. nov., are introduced and represent species that are closely related to Paraphoma but differ based on morphological characters and molecular phylogeny. Phoma coonsii is transferred to genus Chaetosphaeronema that also belongs to the Phaeosphaeriaceae. Pyrenochaetopsis gen. nov. is introduced to accommodate the type species Pyrenochaetopsis leptospora comb. nov., as well as several other species formerly accommodated in Phoma and Pyrenochaeta. Pyrenochaetopsis is closely related to Pyrenochaeta and classified in the Cucurbitariaceae. Pleurophoma cava is transferred to genus Pyrenochaeta. The new genera elucidate the confusing taxonomy of species in genera Phoma, Pyrenochaeta and Pleurophoma and recognize monophyletic genera with distinct teleomorph affinities.     

Outbreaks of phaeohyphomycosis in the chinook salmon (Oncorhynchus tshawytscha) caused by Phoma herbarum

Phoma herbarum has been associated with two outbreaks of systemic mycosis in hatchery-reared chinook salmon (Oncorhynchus tshawytscha) fingerlings. Affected fish exhibited abnormal swimming behavior, exophthalmia, multiple rounded areas of muscle softening, protruded hemorrhagic vents, and abdominal swelling. In all affected fish, swimbladders were filled with whitish creamy viscous fungal mass, surrounded by dark red areas in swimbladder walls, kidneys, and musculature. Clinical and histopathological examinations suggest that the infection may have started primarily in the swimbladder and then spread to the kidneys, gastrointestinal tract, and surrounding musculature. Consistent microscopical findings included broad septate branched fungal hyaline hyphae, 5–12 μm in diameter within the swimbladder, stomach, and often within and adjacent to blood vessels. Profuse growths of woolly brown fungal colonies were obtained from swimbladders and kidneys on Sabouraud medium. On corn meal agar the formation of pycnidia, characteristic of Phoma spp., was detected within 10 days of incubation. Morphological and molecular analyses identified this fungus as Phoma herbarum. This report underscores systemic fungal infections as a threat to raceway-raised salmon.     

Phoma glomerata as a mycoparasite of powdery mildew

Ampelomyces and Phoma species are frequently confused with each other. Isolates previously attributed to the genus Ampelomyces were shown to be Phoma isolates through studies of their morphology and life cycle and ribosomal DNA internal transcribed spacer region 1 sequence analysis. Phoma glomerata can colonize and suppress development of powdery mildew on oak and may have utility as a mycoparasitic agent.     

An endophytic/pathogenic Phoma sp. from creosote bush producing biologically active volatile compounds having fuel potential

A Phoma sp. was isolated and characterized as endophytic and as a pathogen of Larrea tridentata (creosote bush) growing in the desert region of southern Utah, USA. This fungus produces a unique mixture of volatile organic compounds (VOCs), including a series of sesquiterpenoids, some alcohols and several reduced naphthalene derivatives. Trans-caryophyllene, a product in the fungal VOCs, was also noted in the VOCs of this pungent plant. The gases of Phoma sp. possess antifungal properties and is markedly similar to that of a methanolic extract of the host plant. Some of the test organisms with the greatest sensitivity to the Phoma sp. VOCs were Verticillium, Ceratocystis, Cercospora and Sclerotinia while those being the least sensitive were Trichoderma, Colletotrichum and Aspergillus. We discuss the possible involvement of VOC production by the fungus and its role in the biology/ecology of the fungus/plant/environmental relationship with implications for utilization as an energy source.     

Skyttea richardsonii sp. nov. from Maine, with a key to the species known from North America

Skyttea richardsonii sp. nov. is described from a sterile corticolous lichen in Maine. It is closest to S. tavaresae, the only other member of the genus to be reported as having annelations on the excipular hairs, but that species occurs on Loxospora spp. and differs in the K+ reaction of the exciple and ascospore size. Minute Phoma-like conidiomata found in some apothecia may represent an independent fungicolous fungus growing on the new species. This is the 10th species of the genus to have been discovered in North America; a key to these species is provided.     

Fungal Assciations: I. Synergistic Relation between Rhizoctonia solani Kuhn and Fusarium solani Snyder and Hansen in causing a Potato Tuber Rot

Rhizoctonia solani, Fusarium solani, and Phoma foveata werechosen for the study of disease caused by these fungi in differentcombinations in potato tubers. An initial Rhizoctonia infection,when followed by a Fusarium infection, gave an extensive rottingwith external pimple-like formations in some cases. This typeof rotting could not be brought about by individual infectionswith either of the two fungi, or jointly by them when Fusariumwas inoculated first. Microscopic observations of infected matureand young potato tubers showed that Rhizoctonia grew intracellularlywhen infected alone, whereas it grew inter- as well as intra-cellularlyin the successive double infection. Fusarium formed more haustorium-likestructures when inoculated alone that when it followed Rhizoctonia.The length of these structures in the double infection was greaterin mature than in young tubers. Atmospheric humidity affectedthe amount of rotting, the shape and colour of the rot, andthe morphology of the fungus in the tissue.     

Evidence of the production of silver nanoparticles via pretreatment of Phoma sp.3.2883 with silver nitrate

AIMS: The objective was to demonstrate the size of silver particles produced by the filamentous fungus Phoma sp.3.2883 via adsorption and accumulation, and to confirm that this silver was in a reduced state. METHODS AND RESULTS: Mycelium was freeze-dried and then shake-cultured in a silver nitrate solution. It was found that up to 13.4 mg of silver was produced per gram of dry mycelium via atomic absorption spectrometer (AAS) analysis. The silver particles adsorbed on the mycelium were observed and measured under transmission electron microscope and their estimated size was 71.06 +/- 3.46 nm. Further examination of the particles via X-ray photoelectron spectroscope confirmed that the adsorbed silver particle had been reduced. CONCLUSION: The frozen mycelium of Phoma sp3.2883 has the potential for use in silver nanoparticle production. SIGNIFICANCE AND IMPACT OF THE STUDY: Silver nanoparticles could be used in the oil industry as an important catalyst and in the field of human medicine as a bactericide. The fungus Phoma sp3.2883 is a potential biosorbent that could be used for the production of these silver nanoparticles, and may also be useful in waste detoxification and in silver recovery programmes.     

Analysis of the mating-type loci of co-occurring and phylogenetically related species of Ascochyta and Phoma

Ascochyta and Phoma are fungal genera containing several important plant pathogenic species. These genera are morphologically similar, and recent molecular studies performed to unravel their phylogeny have resulted in the establishment of several new genera within the newly erected Didymellaceae family. An analysis of the structure of fungal mating-type genes can contribute to a better understanding of the taxonomic relationships of these plant pathogens, and may shed some light on their evolution and on differences in sexual strategy and pathogenicity. We analysed the mating-type loci of phylogenetically closely related Ascochyta and Phoma species (Phoma clematidina, Didymella vitalbina, Didymella clematidis, Peyronellaea pinodes and Peyronellaea pinodella) that co-occur on the same hosts, either on Clematis or Pisum. The results confirm that the mating-type genes provide the information to distinguish between the homothallic Pey. pinodes (formerly Ascochyta pinodes) and the heterothallic Pey. pinodella (formerly Phoma pinodella), and indicate the close phylogenetic relationship between these two species that are part of the disease complex responsible for Ascochyta blight on pea. Furthermore, our analysis of the mating-type genes of the fungal species responsible for causing wilt of Clematis sp. revealed that the heterothallic D. vitalbina (Phoma anamorph) is more closely related to the homothallic D. clematidis (Ascochyta anamorph) than to the heterothallic P. clematidina. Finally, our results indicate that homothallism in D. clematidis resulted from a single crossover between MAT1-1 and MAT1-2 sequences of heterothallic ancestors, whereas a single crossover event followed by an inversion of a fused MAT1/2 locus resulted in homothallism in Pey. pinodes.     

Taxonomical re-evaluation of Phoma-like soybean pathogenic fungi

Coelomycetous fungi classified in Ascochyta, Phoma, and Phyllosticta have been recorded from spots on leaves and pods of soybeans. Based on the Genealogical Concordance Phylogenetic Species Concept, the authors suggest the re-evaluation of the taxonomic status of Phoma sojicola (syn. = Ascochyta sojicola) and Phyllosticta sojicola. In spite of the former delimitation of Phoma sojicola based on small differences in morphological features, it has proved to be identical to Phoma pinodella. Similarly, it was also confirmed that Phyllosticta sojicola was identical to Phoma exigua var. exigua. The authors supply tools for identification of Phoma-like fungi by combined conventional and molecular methods. Protein-encoding genes (tef1 and β-tubulin) were successfully applied within the Phoma genus to infer phylogenetic relationships.     

Fungal degradation of aflatoxin B1

A number of fungal cultures were screened to select an organism suitable to be used in the detoxification of aflatoxin B1. They were co-cultured in Czapek-Dox-Casamino acid medium with aflatoxin B1 producing Aspergillus flavus. Several fungal cultures were found to prevent synthesis of aflatoxin B1 in liquid culture medium. Among these Phoma sp., Mucor sp., Trichoderma harzianum, Trichoderma sp. 639, Rhizopus sp. 663, Rhizopus sp. 710, Rhizopus sp. 668, Alternaria sp. and some strains belonging to the Sporotrichum group (ADA IV B14(a), ADA SF VI BF (9), strain 720) could inhibit aflatoxin synthesis by > or =90%. A few fungi, namely ADA IV B1, ADA F1, ADA F8, also belonging to the Sporotrichum group, were less efficient than the Phoma sp. The Cladosporium sp. and A. terreus sp. were by far the least efficient, registering <10% inhibition. The cultures which prevent aflatoxin biosynthesis are also capable of degrading the preformed toxin. Among these, Phoma sp. was the most efficient destroying about 99% of aflatoxin B1. The cell free extract of Phoma sp. destroyed nearly 50 microg aflatoxin B1 100 ml(-1) culture medium (90% of the added toxin), and this was more effective than its own culture filtrate over 5 days incubation at 28+/-2 degrees C. The degradation was gradual: 35% at 24 h, 58% at 48 h, 65% at 72 h, 85% at 96 h and 90% at 120 h. The possibility of a heat stable enzymatic activity in the cell free extract of Phoma is proposed.     

Molecular and genetic analyses of geographic variation in isolates of Phoma macrostoma used for biological weed control

Molecular and genetic approaches were used to evaluate the genetic relatedness among isolates of the fungus Phoma macrostoma Montagne originating from Canada and Europe and to other species in the genus Phoma. Distinct differences were observed in genetic variation among nine species of the genus Phoma. Randomly amplified polymorphic DNA (RAPD) revealed the presence of intraspecific genetic variation among the isolates of P. macrostoma, with the isolates being used for biological weed control being distributed in a distinct phylogenetic cluster. Additional variation within the biocontrol isolate cluster in P. macrostoma was revealed by pulsed field gel electrophoresis (PFGE), which showed that biocontrol isolates generated two different chromosomal profiles, however the profiles did not relate to their Canadian ecozone origin. Mating studies showed that biocontrol isolates of P. macrostoma from Canada did not produce sexual reproductive structures and were incapable of crossing. These studies also confirmed that no obvious differentiation exists among the biocontrol isolates of P. macrostoma from Canadian Ecozones 3 and 4.     

Some observations on assessing Phoma betae infection of sugar-beet seed

Near-ultraviolet or ‘black’ light applied continuously from the start of incubation, facilitates tests for Phoma betae on sugar-beet seed by stimulating the production of pycnidia and restricting mycelial growth of P. betae and other fungi. Pretreatment of the seed with dilute sodium hypochlorite decreases the number of seeds with P. betae by removing superficial infection, but some of this is of significance in the field. Rubbing beet seed also decreased counts of P. betae in the laboratory and increased field emergence, primarily by removing the fungus. Griseofulvin sprayed on beet-seed plants either 2 wk or 2 days before harvest significantly decreased seed infection with P. betae, but not to a level at which further seed treatment could be omitted.     

Endophytic and epiphytic phyllosphere fungi of Camellia japonica: seasonal and leaf age-dependent variations

Seasonal and leaf age-dependent variations in the endophytic and epiphytic phyllosphere fungal assemblages of Camellia japonica were examined and compared. Live leaves of C. japonica were collected in four seasons (May, Aug, Nov, Feb), and fungi were isolated from healthy-looking leaves of 0, 1, 2 and 3 y old. The infection rate and total number of endophytic fungi increased May-Feb, and species richness of endophytes increased as leaves aged. In contrast the infection rate of epiphytic fungi was 100% for all leaf ages at every sampling date. The total number of epiphytic fungi isolated was greatest in May and lowest in Aug. The species richness of epiphytes did not differ significantly by season or leaf age. Eight fungal species were recorded as major phyllosphere fungi of C. japonica. Seasonal variations were detected for the frequencies of Colletotrichum gloeosporioides, C. acutatum, and epiphytes Pestalotiopsis sp.1, Aureobasidium pullulans, Phoma sp.1 and Ramichloridium sp., whereas the frequency of the endophyte Geniculosporium sp.1 varied with leaf age. The frequency of the epiphyte Cladosporium cladosporioides varied with both season and leaf age.     

Endophoma, a new didymellaceous endoconidial genus from bat-cave soil

A new endoconidial taxon, Endophoma elongata gen. et sp. nov., isolated from bat-cave soil, is reported from Alberta, Canada. It is morphologically unique in producing two forms of unilocular, endoconidial conidiomata (i.e. a superficially Phoma-like spherical, often ostiolate form and a cylindrical, non-ostiolate, often setose cleistopycnidial form). Locules of both forms are pseudoparenchymatous, filled with hyaline, thin-walled, endoconidial conidiogenous cells. Endoconidia are hyaline and unicellular. One- or two-celled chlamydospores are abundant in culture. Phylogenetic analysis of the LSU, ITS and β-tubulin regions indicates Endophoma is a member of the Didymellaceae and remote from all other endoconidial genera. Endoconidiogenesis has not been reported previously within the Didymellaceae, and Endophoma represents the first report of a coelomycetous, endoconidial genus in the Pleosporales.     

Factors affecting the occurrence of gangrene (Phoma exigua) in potatoes

The presence in soil from Scotland and England of Phoma exigua f. sp. exigua and P. exigua f.sp. foveata, which cause gangrene, is confirmed by isolation, and it is established that infection of tubers occurs before lifting, and after lifting from soil adhering to tubers. The distribution of the disease is related to soil moisture, gangrene being most prevalent in tubers from the north-eastern counties of Scotland where the moisture content of arable soils remains high throughout the growing season. The incidence of the disease may be affected by the haulm, either as a source of infection—though not an important source—or by its effect on the maturity of the tubers. The incidence of gangrene is less where haulm destruction is rapid. The incidence of gangrene in a crop is not related to its incidence in the seed tubers planted and, unless infection is severe, the effect on yield is not serious. Symptoms of skin necrosis were associated with tubers from acid soils, infected with P. exigua f.sp. foveata and stored at low temperature.     

N-acetyl-beta-D-hexosaminidase secreted by the marine fungus Phoma glomerata

Among the ten strains of marine fungi studied, the mycelial fungus Phoma glomerata showed maximum potency in producing N-acetyl-beta-D-glucosaminidase. The conditions for fungal growth and enzyme biosynthesis were evaluated. N-acetyl-beta-D-hexosaminidase was isolated from the culture liquid of Phoma glomerata by ion-exchange chromatography (on DEAE-cellulose and DEAE-Sephacell) and gel filtration (on Toyopearl HW-55) with a yield of 35%; the enzyme, purified 36.4-fold, had a molecular weight of 20 kDa. The homogeneity of the enzyme was confirmed by gel filtration and SDS-PAGE. Transglycosylation reactions catalyzed by the enzyme produced N-acetyl-D-glucosamine and N-acetyl-D-galactosamine with respective yields of 38 and 46%.     

Inhibition of Some Rot Fungi Polygalacturonases by Allium cepa L. and Allium porrum L. Extracts

Extracts of Allium cepa and A. porrum - contain factors that inhibit to various extents polygalacturonases (PGs) produced in vitro by Sclerotinia sclerotiorum, Botrytis cinerea, Fusarium moniliforme, Phoma terrestris, Sclerotium cepivorum, Macrophomina phaseolina, Didymella bryoniae and Phoma lycopersici. The PG inhibition rank changed using leek or onion extract. The inhibition factors are possibly proteins, do not present particular specificity and act against PGs of fungi pathogens and non pathogens for these plant species.     

Phoma nigrificans (P. Karst.) Boerema et al., a New Species for Poland

Phoma nigrificans was isoiated from leaves of Thlaspi arvense. The cultural characteristics are described, and results of comparative pathogenicity tests including Phoma lingam isolates on B. napus var. oleifera and T. arvense are given. This is the first report of P. nigrificans from Poland.