Genus Phoma Research Articles

A Cyclic Carbonate and Related Polyketides from a Marine‐Derived Fungus of the Genus Phoma

AbstractFor Abstract see ChemInform Abstract in Full Text.

A cyclic carbonate and related polyketides from a marine-derived fungus of the genus Phoma

Two metabolites, phomoxin and phomoxide, as well as the previously synthesized antibiotic eupenoxide, have been isolated from the fermentation broth of a marine-derived fungus of the genus Phoma (strain CNC-651). The new compounds are highly oxygenated polyketides of a new structural class. Phomoxin contains an unusual cyclic carbonate functionality that is rare among natural products. The structures of the new metabolites were assigned by spectroscopic methods that relied heavily on 2D NMR spectroscopic analysis.

Sorghum head-bugs and grain molds in West and Central Africa: I. Host plant resistance and bug–mold interactions on sorghum grains

A regional sorghum head-bug and grain mold resistance trial was conducted in 1996 and 1997 at 15 and 13 research stations located in 10 West and Central African countries, respectively. Two cultivars namely IS 14384 and CGM 39/17-2-2 exhibited consistently high levels of resistance both to head-bugs and grain molds over years and localities. Eurystylus oldi was the dominant head-bug species at all localities except in Benin, Chad and Guinea. Sorghum grain mycoflora varied little between sites with genera Phoma and Fusarium dominating, followed by Curvularia. Efficiency of the insecticidal treatment on head-bug incidence partially confirmed the critical role played by head-bugs in aggravating mold infection.

Phoma sp. FOM-8108, a producer of gentisylquinones, isolated from sea sand

A fungal strain, FOM-8108, that was isolated from sea sand was found to produce gentisylquinone and chlorogentisylquinone, inhibitors of neutral sphingomyelinase. The fungus grew well under normal conditions, in the darkness, or on various agar media, but typical morphological characteristics were not observed to determine its taxonomy. Therefore, culture conditions were studied extensively, resulting in formation of a number of pycnidia by the fungus on the media containing seawater or on natural substrates such as hydrangea leaves, gardenia leaves, and rice straw under natural light or near-ultraviolet radiation exposure. Eventually, from the morphological characteristics of pycnidia, conidiogenous cells, and conidia, strain FOM-8108 was considered to belong to the genus Phoma. Culture studies showed seawater in the fermentation medium was necessary for the strain to produce gentisylquinones. Particularly, a full production of chlorogentisylquinone, which has a chloride ion in the structure, was performed in the medium with higher concentration (75%–100%) of seawater.

Foliar pathogen and insect herbivore effects on two landslide tree species in Puerto Rico

To better understand pathogen/herbivore interactions and landslide regeneration, percent leaf area lost to disease and herbivory on two Puerto Rican trees over a 1-year period was sampled. Cecropia schreberiana saplings lost from 1 to 3% leaf area to pathogens and from 1 to 7% to herbivores. For Inga vera, both sapling and seedling losses to pathogens were minimal, but Inga herbivory losses reached 25% for saplings and 34% for seedlings. The most common fungi on Cecropia leaves were species in the genera Phoma and Phyllosticta, and on Inga leaves was Colletotrichum gloeosporioides. Percent survivorship after 1 year in the field varied among species and life-form (46% for Cecropia saplings, 15% for Inga saplings, 0% for Inga seedlings). There were no effects of pathogens or herbivores on survivorship or growth, but increased levels of herbivory did significantly correlate with total phenolics and condensed tannins in both Inga seedlings and saplings. For both seedlings and saplings of two trees on the neotropic island of Puerto Rico: (1) leaf herbivory was modest and leaf losses to pathogen disease were small; (2) these mechanisms did not affect survivorship or growth; (3) a neotropical tree ( I. vera) displayed increased levels of secondary chemicals in its leaves, correlated with increased levels of insect herbivory.

Occurrence of Neutral and Alkaline Cellulases among Alkali-tolerant Micromycetes

600 different natural strains of alkali-tolerant micromycetes belonging to 4 classes, 38 genera and 119 species were tested on their ability to produce neutral and alkaline cellulases. Frequency of occurrence of neutral and alkaline cellulases producers among the studied strains was estimated. It is concluded that 72% of all tested strains produce cellulases at neutral and alkaline pH values. But the largest number of neutral and alkaline cellulases producers belong to the following classes which are tolerant to extreme environmental factors: namely Hyphomycetes (genera Acremonium, Alternaria, Cylindrocarpon, Fuzarium, Penicillium, Verticillium, Myrothecium, Ulocladium, Gliocladium), Ascomycetes (genus Chaetomium) and Coelomycetes (genera Phoma, Microsphaeropsis, Aposphaeria).

Cretaceous Deuteromycetes on a Cycadeoidalean Bisexual Cone

Well‐preserved fossil fungal bodies of four different morphologies were discovered on and in a permineralized bisexual cone of a Cretaceous cycadeoid, Cycadeoidella japonica Ogura. Three are identified as Coelomycetes based on the formation of numerous conidia in the pycnidial cavities or acervuli characteristic of the group. The other form shows a less diagnostic hyphal aggregation and can only be assigned to Deuteromycetes. Each of the three Coelomycetes is described as a new organ genera: Archephoma gen. nov., Meniscoideisporites gen. nov., and Palaeodiplodites gen. nov. Archephoma is comparable to the modern genus Phoma. Meniscoideisporites, characterized by meniscoid conidia, is not attributable to any living taxa based on reliable taxonomic characters. Palaeodiplodites gen. nov. is similar to modern genus Diplodia but has two conidiomatal types, pycnidial and acervular. These coelomycetous fossils are new to the fungal record earlier than the Tertiary and provide evidence for resolving the evolution...

Phylogenetic and developmental evidence supporting reclassification of cruciferous pathogens Phoma lingam and Phoma wasabiae in Plenodomus

To evaluate the classification of Phoma lingam (Tode:Fr.) Desm. and Phoma wasabiae Yokogi in the genus Phoma, a phylogenetic study of Phoma spp. was conducted using ribosomal DNA internal transcribed spacer 1 sequences. The majority of the Phoma species included in the study clustered in a Phoma-Didymella clade (Venturiaceae). Phoma lingam and P. wasabiae consistently clustered outside of the Phoma-Didymella clade, instead forming the Plenodomus clade (Leptosphaeriaceae). This result supports classification of P. lingam and P. wasabiae in Plenodomus as has been proposed by earlier investigators. Features of the morphology and development of pycnidia of Phoma americana Morgan-Jones & White and P. lingam suggest that Phoma and Plenodomus may also be distinguishable morphologically. Our results suggest that difficulties of identification and classification in Phoma may be resolved by using a phylogenetic approach to classification.Key words: Coelomycetes, molecular systematics, pathogens, taxonomy.

Taxonomy of Orphnodactylis kalmiae gen. et sp.nov. influenced by the hyperparasite Didymosphaeria kalmiae

The holotype of Dothidea kalmiae Peck, putitive cause of the twig blight disease of Kalmia angustifolia (Ericaceae) in North America, was examined and found to contain two species of ascomycetes. The original diagnosis of D. kalmiae included elements of both fungi. Additional material from other parts of North America were also examined and found to contain these two fungi. The two ascomycetes are determined to be (1) a member of the Phyllachoracecae characterized by black stromata and parasitic on Kalmia spp., and (2) a member of the genus Didymosphaeria parasitic in the ascomata of the first species. For reasons of nomenclatural stability and the availability of useful holotypes, Dothidea kalmiae is chosen to represent the hyperparasite and transferred to Didymosphaeria as Didymosphaeria kalmiae (Peck) Malloch and Mallik comb.nov. The species causing the twig blight is described as the type of the new genus and species Orphnodactylis kalmiae. Phyllachora wittrockii, the agent of a similar disease of Linnaea borealis (Caprifoliaceae), is transferred to Orphnodactylis as Orphnodactylis wittrockii (Erikss.) Malloch and Mallik. Two coelomycetes, members of the genera Diplodina and Phoma recorded in stromata of O. kalmiae by previous workers are described and illustrated. The life history of O. kalmiae is discussed briefly.Key words: Kalmia, sheep laurel, Didymosphaeria, Orphnodactylis, Phyllachora, hyperparasitism.

A visceral mycosis in ayu fry, Plecoglossus altivelis Temminck & Schlegel, caused by a species of Phoma

Abstract. Epizootics and histopathology of a new visceral mycosis due to fungi impefecti which occurred in farmed ayu, Plecoglossus altivelis Temminck & Schlegel, in Tokushima Prefecture, Japan are described. Histopathological examination suggested that fungal infection occurred primarily in the airbladder. A fungus with characteristics of the genus Phoma isolated from diseased fish is described and its taxonomic position discussed.

A mycological survey of the South Adriatic Sea

A total of 498 fungal isolates belonging to 33 genera and 90 species were identified in the course of a 2-yr survey of the southern part of the territoreal waters of the Yugoslav Adriatic Sea. The best represented genus was Penicillium (32.12% of the total number of isolates), the P. chrysogenumnotatum series being the most abundant, followed by P. verrucosum var. cyclopium, and P. brevicompactum The genus Aspergillus represented 22.28% of the total. A. versicolor being the most ubiquitous. The Dematiaceae as a group, with 148 isolates included in 14 genera and 26 species, accounted for 29.71% of the total; the dominant genera were Cladosporium, Alternaria, and Ulcladium, with 14 25, 5.42 and 4.21%, respectively of the total number of isolates. Hyphomycetes with hyaloconidia, with 46 isolates included in 9 genera and 20 species, constituted about 8.83%, the best represented genus in this group being Fusarium, with 10 identified species. The Sphaeropsidales accounted for 5.42% of the total number of isolates, the genus Phoma being the most abundant. The number of isolates obtained from surface waters accounted for 85% of the total. The decreasing number of isolates in the water column was particularly evident in the case of the most ubiquitous species, a fact which may be explained by the influence of the contact of water masses with the atmosphere and the lower salinity of the surface waters. The distance from the shore as well as the human factor is reflected in the number of isolates and species. The ecological factors influenced not only the fungal population densities, but also their quality.

Infraspecific categories in fungi

The problems facing the mycologist centre on the difficulty of distinguishing between the individual and the population, the degree of host or substratum specialization and the limited range of morphological characters available for use as denning taxa. The use of the categories ‘variety’ and ‘forma specialis’ is considered, and examples are given of their application in the cereal rusts and in the genera Phoma and Fusarium. Micro-evolutionary trends in Auricula auricula are also considered and are used to illustrate how amenable fungi are to studies on speciation.

Infraspecific categories in fungi

The problems facing the mycologist centre on the difficulty of distinguishing between the individual and the population, the degree of host or substratum specialization and the limited range of morphological characters available for use as denning taxa. The use of the categories ‘variety’ and ‘forma specialis’ is considered, and examples are given of their application in the cereal rusts and in the genera Phoma and Fusarium. Micro-evolutionary trends in Auricula auricula are also considered and are used to illustrate how amenable fungi are to studies on speciation.

The Dictyochlamydospore of Peyronellaea Glomerata (Corda) Goidanich Ex Togliani Contrasted with the Dictyoporospore of Alternaria Tenuis Auct.

SUMMARYThe differences which exist between the dictyochlamydospore of Peyronellaea and the dictyoporospore of Alternaria are summarized as follows:1. The dictyochlamydospore of Peyronellaea is a non-deciduous spore fitting the general definition of a thallospore and more specifically that of a chlamydospore. When the elements in a spore chain break apart a ragged edge is left on each spore indicating the place of attachment to the previous spore.2. The dictyochlamydospore is composed of an outer wall which is separable from the walls of the component cells within the compound spore. The component cells of the dictyochlamydospore are rather easily separable from each other. Miniature pycnidia may occur between the elements in a dictyochlamydospore chain.3. The Alternaria spore is a deciduous spore and fits the definition of a conidium and porospore. When the elements in a spore chain break apart the only indication of attachment to the previous spore is by an almost imperceptible scar at the base and the beak of the spore.4. The Alternaria spore does not appear to be separable into an outer and an inner spore wall and the component cells of the dictyoporospore remain firmly united to one another. Pycnidia are not known to occur in the life cycle of any true Alternaria species.The genus Peyronellaea has been erected upon the presence of two spore forms present in the life cycle of its members. The pycnidial stage is ascribable to the genus Phoma, where it lies among many nondescript organisms of similar fructification. The chlamydosporic stage is distinct and easily recognizable.The term dictyospore is a general term lacking precision in respect to describing mode of spore origin and has been used erroneously to group together entirely different spore types. The dictyospores of Alternaria and Peyronellaea have been used as examples in demonstrating the superficial resemblance of dictyoporospores and dictyochlamydospores when contrasted with their mode of origin, structural difference, and manner of germination.

A NEW ROOT ROT OF FLORISTS' CHRYSANTHEMUMS IN ONTARIO

An apparently undescribed root rot of Chrysanthemum morifolium Ramat. occurred in 1953 on the horticultural variety "White Shasta" in an Ontario greenhouse. The disease was characterized by a severe root rot, general stunting and a foliar chlorosis and necrosis. A species of the form genus Phoma was found associated with the roots of affected plants. The disease has been reproduced repeatedly by inoculation with monoconidal cultures of the fungus. Symptoms appear to be most severe on plants growing in infested soil maintained at temperatures between 55° and 60°F. Inoculation tests suggest that the disease is restricted to the florists' chrysanthemum. Varieties of C. morifolium do, however, vary widely in their susceptibility to this root rot. There is no evidence that the pathogen is carried within cuttings taken from infected plants. Both steam sterlization and methyl bromide fumigation have completely eliminated the pathogen from infested soils.

Species Placed by Saccardo in the Genus Phoma. Part III

Species Placed by Saccardo in the Genus Phoma. Part III

Species Placed by Saccardo in the Genus Phoma

Species Placed by Saccardo in the Genus Phoma

Species Placed by Saccardo in the Genus Phoma. Part II

Species Placed by Saccardo in the Genus Phoma. Part II