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Una enfermedad foliar fue detectada en la plantación comercial de Khaya senegalensis con 3 anos de edad, en la localidad de Huimanguillo (Tabasco, México). Mediante la caracterización morfológica y molecular, y por el cumplimiento de los postulados de Koch, se determinó que el agente causal corresponde al hongo Sclerotium coffeicola. Este es el primer reporte de S. coffeicola causando mancha foliar en caoba africana en México. A foliar disease was detected in the commercial plantation of Khaya senegalen with three years of age in Huimanguillo, Tabasco, Mexico. Through the morphological and molecular characterization and the compliance of the Koch's postulates, it was concluded that the causal agent corresponds to the fungus Sclerotium coffeicola. This is the first report of S. coffeicola causing leaf spot on African mahogany in Mexico.

The study of genetic variation in fungi has been poor since the development of the theoretical underpinnings of population genetics, specifically in marine taxa. Corollospora maritima sensu lato is an abundant cosmopolitan marine fungus, playing a crucial ecological role in the intertidal environment. We evaluated the extent and distribution of the genetic diversity in the nuclear ribosomal internal transcribed spacer region of 110 isolates of this ascomycete from 19 locations in the Gulf of Mexico, Caribbean Sea and Pacific Ocean. The diversity estimates demonstrated that C. maritima sensu lato possesses a high genetic diversity compared to other cosmopolitan fungi, with the highest levels of variability in the Caribbean Sea. Globally, we registered 28 haplotypes, out of which 11 were specific to the Caribbean Sea, implying these populations are genetically unique. We detected populations inhabiting human-impacted sites with null genetic variation. As long-term exposure to contaminants has been proven to decrease genetic diversity, a conservation genetics approach to assess this matter is urgent. Our results revealed the occurrence of five genetic lineages with distinctive environmental preferences and an overlapping geographical distribution, agreeing with previous studies reporting physiological races within this species.

Globally marine fungal diversity is poorly known, especially in Mexico. We evaluated the diversity of marine ascomycetes on five tourist beaches on Cozumel Island in September 2004, and in February 2007. Fifty sample units were collected randomly from each beach during each sampling time. Seven species were recovered, of which Lindra thalassiae and Corollospora maritima were the most dominant species. Corollospora gracilis and Lulworthia grandispora are new records for Cozumel Island. The highest diversity value was found in San Francisco beach, probably because the surrounding coral reefs are an important source of a wide variety of substrata for these fungi.

The coastline of Tabasco State in the Gulf of Mexico represents a highly deteriorated ecosystem, where densely populated human settlements and large offshore petroleum developments are negatively affecting the marine biodiversity. Previous work on marine ascomycetes reported that in the Gulf of Mexico the diversity of these fungi might be threatened by anthropogenic activities. Therefore we evaluated the diversity of marine ascomycetes in this area, and registered 19 taxa. Ceriosporopsis capillacea was recorded for the first time for Mexico. The highest diversity was obtained in the beach of Sánchez Magallanes, which receives a great quantity and diversity of organic remains originating from El Carmen/Machona mangrove forests via the Santa Ana mouth, benefiting the proliferation of marine fungi. The lowest diversity was documented in the beach of Paraíso, which is close to the delta of one of the most polluted rivers in Mexico and to off-shore oil extraction platforms. We found a significant correlation between the community composition and abundance, implying that the overall abundance is defined by the community structure, perhaps as a result of competition. Additionally, our results indicated that there is no relationship between the grain size and the biodiversity observed.

Bioactivity-directed fractionation of the organic mycelium extract of the endophytic fungus Acremonium camptosporum W. Gams (Clavicipitaceae), isolated from the leaves of Bursera simaruba (Burseraceae), led to the isolation of six major heterodimeric polyketides, including one not previously characterized acremoxanthone derivative. In addition, the already known acremoxanthone C, acremonidins A and B, and acremoxanthones A and B were obtained. The structure of the new compound was established by extensive NMR studies, including DEPT, COSY, NOESY, HSQC, and HMBC methods. The trivial name proposed for this compound is acremoxanthone E. In addition, the structure of acremoxanthone C was unequivocally established for the first time, through X-ray crystal-structure analysis. The anti-oomycete activities of the pure compounds were tested against four economically important phytopathogenic oomycetes. Inhibitory concentration for 50% diameter growth reduction, IC50 , values for the four phytopathogens ranged from 6 to 38 μM. Also, in parallel, the cytotoxic activities against six cancer cell lines were evaluated showing IC50 values similar to those of cisplatin. To the best of our knowledge, this is the first report on three different groups of heterodimeric polyketides, linked by a bicyclo[3.2.2]nonene, such as xanthoquinodins, acremonidins, and acremoxanthones, which are isolated from an endophytic fungus. In addition, a common biosynthetic origin could be proposed.

Diversity of marine fungi in the Gulf of Mexico remains unknown for the most part, therefore the geographical distribution patterns of these microorganisms are mostly unknown too. Twelve sandy beaches located in this sea were sampled to evaluate the diversity of marine fungi, revealed by fruiting on natural substrata incubated in the laboratory for up to 12 months. Species richness and diversity differed between beaches, and corresponded with the presence of main and highly polluted river mouths, nearshore marine environments, and core industrial and port developments. Contaminants and local anthropogenic activities may be reducing the diversity of marine ascomycetes. Connections between beaches and different nearshore habitats explain the high diversity observed, since they represent a varied source of substrata for decomposition and heterogeneous environmental conditions. We recognized four main local species distribution patterns. Moreover, the constrained correspondence analysis showed that temperature is a major environmental variable affecting the distribution of these fungi. By a linear regression we showed a significant relationship between temperature and diversity.

A foliar disease was detected in the commercial plantation of Khaya senegalensis with three years of age in Huimanguillo, Tabasco, Mexico. Through the morphological and molecular characterization and the compliance of the Koch's postulates, it was concluded that the causal agent corresponds to the fungus Sclerotium coffeicola. This is the first report of S. coffeicola causing leaf spot on African mahogany in Mexico.

A BSTRACT .— Collecting trips in the American tropics have yielded two unusual specimens of Scutellinia. Although assigned to existing species, these specimens exhibit subtle differences from the descriptions of both species. Normally red to brownish red, a specimen of Scutellinia balansae was collected on decaying banana leaves in Venezuela that has a yellow hymenium. In Scutellinia blumenaviensis the hymenium is usually bright red, brownish red to grayish, however, a specimen with a golden-yellow hymenium was collected on a rotting log in the northeastern lowlands of Ecuador. Descriptions and illustrations of these two species are provided.

During a study on the fungal endophytic associations with some trees of the secondary forest of El Eden Ecological Reserve located in the northeastern Yucatan Peninsula of Mexico, a new fungal species was isolated as an endophyte of a tree named chakah, chachah, or hukup (Bursera simaruba) by indigenous Mayas. This fungus is characterized by producing a strong musty odor and absence of reproductive structures. Cultures of this fungus on PDA form a whitish, flocculose colony with an uncolored reverse and a mycelium that grows slowly. Scanning electron microscopy photographs showed in aerial and submerged mycelium the early formation of unique intercalary swollen, thin-walled, rugulose hyphae. Based on morphological and DNA sequence analyses, the Mexican isolate is a member of the Xylariales with high similarity to Muscodor albus and the related species Muscodor vitigenus, but with distinct differences that is here described and illustrated as Muscodor yucatanensis sp. nov.

Mexico, with a land surface area of 1.97 M sq. km., has a topography that varies from high plains in the north, to tall volcanic mountains in the south-central region, to lowlands in the south, as well as extensive coastlines. Southern Mexico is the area where the temperate climate of North America unites with the tropical climate of Central and South America, resulting in a highly diverse ecosystem that supports an abundant biota, including ascomycetes. The mycological literature was reviewed for records of ascomycetes from Mexico, which yielded 1,331 species plus 24 varieties, for a total of 1,355 identified taxa of ascomycetes known from the country. Approximately 35% of these are lichenized. The anamorphic ascomycetes were not included in this compilation. Taxonomically, these ascomycetes are distributed among 414 genera belonging to 41 orders and 126 families. The Xylariales is the best studied group, with 100 species of Xylaria and 48 species of Hypoxylon recorded . Other common genera are Parmotrema (36), Laboulbenia (32), Cladonia (30), Podospora (29), Heterodermia (27), Meliola (22), Sporormiella (21) and Hypotrachyna (21). Peziza and Morchella are the most common discomycetes, with 14 and 13 species, respectively. With regard to geographical distribution, the most explored areas in the country are the State of Veracruz, the State of Mexico, the State of Oaxaca, and the State of Chiapas located in the central-southeast region of the country, and the least studied areas are the State of Nayarit, the State of Aguascalientes, and the Peninsula of Baja California.

Basidia of the plant-pathogenic fungus Exobasidium camelliae var. gracilis Shirai became exposed on the abaxial side of an infected leaf of Camellia sasanqua Thunb. following the sloughing of the undersurface of the leaf. Basidia were formed in tremendous numbers in a distinct hymenium that appeared as a white, felt-like layer. Subsequently, colonies of another fungus, Cladosporium sp. appeared, initially as tiny dark dots on this white layer, but quickly increased in size to form larger circular colonies that were olive-brown to dark brown in color. Adjacent colonies sometimes merged to form larger growths with irregular margins that often covered much of the hymenium on the underside of an E. camelliae-infected leaf. The hyphae that made up a young Cladosporium sp. colony were primarily confined to the surface of the E. camelliae hymenium, and we found no evidence that hyphae actually penetrated living basidia. However, E. camelliae basidia overrun by Cladosporium sp. eventually showed signs of necrosis and finally collapsed and died, creating a slightly sunken area in the hymenium. Hyphae of Cladosporium sp. grew throughout the remains of the dead basidia, but did not appear to spread into the leaf tissue above the pseudoparenchymatous layer of hyphae that gave rise to the basidia. Based upon our observations, it is clear that Cladosporium sp. is a necrotrophic mycoparasite. More specifically, it qualifies as a contact necrotrophic, since it kills basidia without first penetrating them with its hyphae.

Poroleprieuria gen. nov. is described and illustrated to accommodate P. rogersii in the Xylariaceae, Xylariales. This ascomycete, known only from the type collection, is characterized by reniform, light brown, smooth ascospores with a germ pore; cylindrical, persistent asci lacking an apical apparatus, septate persistent paraphyses, and erumpent, erect, dark brown, fragile, subcylindrical stromata. The characteristics of this xylariaceous fungus were compared with those of some other ascomycetes having superficially similar cylindrical stromata or ascospores with germ pores.

The perithecial ascomycete Ophiodothella vaccinii causes a leafspot disease of sparkleberry (Vac- cinium arboreum), in which an anamorph is produced early in the life cycle of the fungus. The anamorph forms shiny, black, pulvinate conidiomata that con- tain a single central pore. After initial infection, fun- gal hyphae permeate the interior tissues of the leaf, creating lesions. Conidiomata are initiated by the for- mation of a small layer of intertwined, thicker-walled hyphae beneath the epidermis of the lesion. Near the center of this hyphal layer a subglobose collection of thick-walled hyphae is formed. This hyphal collection grows upward, becoming conical and pressing against the epidermis. Elongation of a columnar apex of the hyphal collection ruptures the epidermis, creating a pore. Subsequent expansion and development of co- nidiophores and conidia push the epidermis upward, lifting it away from the column, opening the pore and allowing conidia to emerge. The conidioma is regarded as a modified acervulus.

In order to evaluate the monophyly of the Phyllachorales from a molecular standpoint and elucidate its phylogenetic relationships with other orders, a segment of the 18S rRNA gene from several representatives of the Phyllachorales, including species of Glomerella, Phyllachora, Coccodiella (=Coccostroma), Sphaerodothis, Ophiodothella, as well as Magnaporthe was sequenced. Maximum Parsimony analysis revealed that the Phyllachorales was a polyphyletic assemblage of taxa. None of the other members of the Phyllachorales, which produced either a clypeus or stroma, clustered with Glomerella. Of the taxa examined, was Coccodiella the closest relative of Phyllachora. Magnaporthe was closely related to the Diaporthales. Our 18S rDNA data highly supported Glomerella being accommodated in a separate family.A ordem Phyllachorales foi avaliada do ponto de vista molecular visando esclarecer a sua relação filogenética com outras ordens. Um fragmento do gene 18S rRNA de diversos representantes dos Phyllachorales, incluindo espécies de Glomerella, Phyllachora, Coccodiella (=Coccostroma), Sphaerodothis, Ophiodothella, como também Magnaporthe foi sequenciado. Análise de parsimônia máxima revelou que a ordem Phyllacholares é polifilética. Nenhum dos outros representantes dos Phyllachorales, que produzem um clipeu ou estroma, se agruparam com Glomerella. Dos taxa estudados, Coccodiella é o mais próximo de Phyllachora. Esses dois gêneros formam um grupo irmão dos Sordariales, que juntos são um grupo irmão dos Diaporthales. Sphaerodothis e Ophiodothella se agruparam dentro dos Hypocreales/Clavicipitales e Xylariales, respectivamente. Magnaporthe é o mais próximo de Diaporthales. Nossos dados de 18S rDNA fortemente suportam Glomerella ser acomodado em uma família distinta.

Ophiodothella caseariae sp. nov. from leaves of Casearia tremula in Venezuela is described and illustrated.

The abundance of hair-bait colonizing fungi was investigated on the beaches of Caracoles, Mocambo, and lcacos, located on the coasts of the Caribbean Sea, Gulf of Mexico and Pacific Ocean, respectively. On each beach a sample of sandy soil was collected. The samples were analyzed by two selective isolation methods for keratinophilic fungi resulting in a total of 544 occurrences. A total of 17 species was found, of which 4 were ascomycetes and 13 hyphomycetes.Gymnascella dankaliensis andAspergillus terreus were the most abundant.Arthroderma curreyi andChrysosporium tropicum were found in low percentages in this survey. From the three beaches sampled, Icacos beach, on the Pacific Ocean coast had the highest number of isolated species.

This is the first ultrastructural study of as- cosporogenesis in Melanospora with deliquescing asci. Electron-opaque vesicles found in the ascogonial cell and the young ascus were involved in the formation of a double-membrane envelope just inside the ascus plasmalemma. The apparent origin of the ascospore- delimiting membrane is described using chemically fixed material. This alternative theory of double- membrane envelope formation as demonstrated in M. zamiae will be worthy of testing in other ascomy- cetes, especially in those shown to have the electron- opaque vesicles. The mature ascospores of M. zamiae were enveloped by two distinctive thick walls, which in fact comprised multiple layers of wall material. Due to the fast process of ascospore maturation, and the difficulties encountered during fixation of such thick-walled spores, the origins of ascospore wall ma- terials in M. zamiae remain unresolved.

A detailed study of ascomal morphology and development in Cercophora palmicola showed that ontogeny is ascohymeniaceous, giving rise to an ostiolate perithecium. Ascomal initials consist of a coiled ascogonium surrounded by several layers of hyphae whose cells become pseudoparenchymatous. The centrum of the young ascoma is composed of a few rows of large, thin-walled pseudoparenchymatous cells that line the ascomal wall, with the central region filled by tightly packed, filamentous paraphyses. The ascogenous system forms along the inside of the layer of pseudoparenchymatous cells at the base of the paraphyses and gives rise to unitunicate asci that grow up among the paraphyses. The wall of the mature perithecium is greatly thickened. It is composed of three regions: a thin outer region of darkly pigmented, angular cells with thickened walls; a broad central region of cells with gelatinized walls; and a thin inner region of flattened cells. Ascomal ontogeny in C. palmicola conforms well to the Sordaria type of development, as defined by Huang. Cercophora palmicolaHanlin & Tortolero is a sordariaceous perithecial ascomycete that occurs on palm stems in the tropics. It possesses several unusual morphological features that were noted in the original description (Hanlin and Tortolero, 1987), but which were not described in detail. The purpose of this paper is to provide additional information on the morphology of C. palmicola and to compare it with information published on related species.

The 30 taxa sampled for this study were chosen based on their taxonomic position or partic- ular morphological characters, which are related to those of Chaetomium. The 15 fungal isolates se- quenced herein were obtained during a fungal bio- diversity survey of tropical soils or from the collec- tions of R.T. Hanlin. Fifteen species were selected from the published data. The aligned sequences of the 5' portion of the 18S ribosomal DNA were ana- lyzed to infer the phylogenetic relationships among Chaetomium and related genera. The sequence data confirmed the generic entity of Achaetomium and placed Ascotricha within the Xylariaceae. The analyses also defined the monophyletic lineage of the Mi- croascaceae and the evolutionary linkages between the families Sordariaceae and Chaetomiaceae. The placement of Coniochaeta in the Coniochaetaceae and Chaetomium and Achaetomium in the Chaetomi- aceae, under the order Sordariales, is supported by

Phylogenetic analyses of partial sequences (1002 basepairs) from the nuclear encoded small subunit ribosomal RNA (18S rRNA) were performed to determine the phylogenetic relationships of the ascostromatic fungi, Botryosphaeria, Guignardia, Leptosphaerulina, Didymella, Venturia, Sporormia , and Sporormiella. Our studies confirm the concept that the subclass Loculoascomycetidae is paraphyletic if Chaetothyriales is included, as this order and the plectomycetes constitute a monophyletic clade that is highly supported in our and some previous phylogenetic analyses. In general, taxa that lack pseudoparaphyses (Dothideales) or have reduced hamathecial tissue, such as Botryosphaeria and Guignardia (sensu Sivanesan), are a sister group to the Pleosporales, the most derived group, whose members have pseudoparaphyses. The two species of Leptosphaerulina , which also lack pseudoparaphyses, clustered within the Pleosporales, rather than within the Dothideales, with high confidence from bootstrap values. Didymella nested within the Pleosporales with a high degree of confidence, and is the sister group to Leptosphaerulina. The taxonomic placement of Venturia and Sporormiella corresponds to the Pleosporales.

The abundance and diversity of species of microfungi was investigated on the beaches of Delfines, Km 24 Veracruz-Alvarado Highway, and El Coco, located on the coasts of the Caribbean Sea, Gulf of Mexico, and the Pacific Ocean, respectively. On each beach a sample composed of sand, subtidal wood or washed-up detritus with moist sand was collected. The samples were analyzed by three different methods, resulting in a total of 1,160 occurrences that fluctuated between 340 and 441 occurrences/sample. The number of species/sample fluctuated between 20 and 32. A total of 52 species was found, of which 12 were marine, and 40 nomarine, of terrestrial origin, and of these 15 were ascomycetes, 34 were hyphomycetes, 2 were blastomycetes and one was a coelomycete. The abundance distribution showed few species with high or low values, with the greates proportion having intermediate values. In order to compare species diversity among the samples frequency curves were utilized, based on the number of species expected from samples taken at random; the results showed that the beach at El Coco was richest in species.

Myriogenospora atramentosa produces partial to complete sterility of host grasses. Geographical and host species distributions were assessed and updated. It is reported only from the New World and appears to be limited to the highly evolved grass tribes Andropogoneae and Paniceae. Included in these tribes are the previously unreported host species Panicum scoparium, Paspalum urvillei, Erianthus brevibarbis, E. contortus, E. giganteus , and hybrids from crosses with Erianthus spp. Additionally, M. atramentosa is reported for the first time growing on Paspalum notatum (bahiagrass), and Panicum hemitomon in South Carolina, U.S.A. Sequence data (ITS regions 1 and 2 and 5·8S rDNA) from several isolates indicated that there is a significant level of DNA sequence differentiation between isolates of M. atramentosa , which suggests that there are at least two distinct sequence groups, or cryptic species, within the currently defined morphological species.

The order Phyllachorales contains ascomycetous fungi of considerable economic importance. The group is represented mostly by foliar parasites which produce perithecia under a clypeus, inside a stroma, or do not produce any stromatic tissue. A major taxonomic problem with this order is the lack of reliable morphological characters that clearly delimit the entire group. The main purpose of this review is to provide a clear picture of the taxonomic relationships of the order Phyllachorales, along with a key to the most important genera in the family Phyllachoraceae.

In Melanospora zamiae a total of five nuclear divisions took place during ascosporogenesis. The first and second divisions were meiotic in which the single diploid nucleus divided into four haploid nuclei. The mitosis that followed gave rise to eight nuclei which characteristically assumed a 1:4:3 (apical:middle:basal) spacing in the clavate ascus. After ascospore delimitation, each nucleus in the young ascospore underwent two successive mitoses producing four haploid nuclei in each spore. Equatorial arrangement of these nuclei was observed in the mature ascospores.

A species of the genusChaetomidium was isolated from fallen leaves of an unknown tree during a mycofloral survey of materials from the ‘Gran Sabana’ region in Southeastern Venezuela. The species was identified asC. heterotrichum. Identification was based on the perithecium lacking a neck and ostiole, the peridium being composed of textura angularis cells, the perithecium being covered with hairs and setae at the apex, and by 4-spored asci containing uniporate ascospores. The anamorph was intermediate betweenChalara andAcremonium sect.Chaetomioides. This is the first report of this species in Venezuela and only the second timeC. heterotrichum has been found. An illustrated description ofC. heterotrichum and a key to eight recognized species ofChaetomidium, based on morphological characters in the literature, are provided. The results of a cladistic analysis of 12 available morphological characters of the genus revealed two main groups, each based on the two characters ‘ascospore shape’ and ‘peridial wall type’. The ascomatal hairs had little influence on the species grouping. With the exception ofC. heterotrichum, the remaining species ofChaetomidium were monophyletically supported in 73% of the bootstrap replicates.Chaetomidium heterotrichum was the basal ingroup taxon and formed a sister group to the other species in the genus.

Microcycle conidiation is defined as the germination of spores by the direct formation of conidia without the intervention of mycelial growth, as occurs in most normal life cycles. It is a method of asexual spore formation in which the normal life cycle of the fungus is bypassed. Spores formed through sexual reproduction and species with unicellular thalli are not included in microcycle conidiation. The term secondary conidium or secondary spore is usually, but not always, synonymous with microcycle conidiation. In the laboratory various factors, but especially temperature, can induce the microcycle condition in such fungi asAspergillus niger, Penicillium andNeurospora crassa, providing a useful tool for research. Microcycle conidiation has also been reported in a broad range of species in nature, and comprises a normal part of the life cycle in several groups, including the Entomophthorales, Taphrinales, Clavicipitales, Uredinales, Ustilaginales, Tremellales and Exobasidiales. The presence of a microcycle in such fungi undoubtedly provides a survival mechanisn for spores that encounter unfavorable conditions.

The perithecial ascomycete Ophiodothella vaccinii causes a leafspot disease of sparkleberry (Vaccinium arboreum), in which an anamorph is produced early in the life cycle of the fungus. The anamorph forms shiny, black, pulvinate conidiomata that contain a single central pore. After initial infection, fungal hyphae permeate the interior tissues of the leaf, creating lesions. Conidiomata are initiated by the formation of a small layer of intertwined, thicker-walled hyphae beneath the epidermis of the lesion. Near the center of this hyphal layer a subglobose collection of thick-walled hyphae is formed. This hyphal collection grows upward, becoming conical and pressing against the epidermis. Elongation of a columnar apex of the hyphal collection ruptures the epidermis, creating a pore. Subsequent expansion and development of conidiophores and conidia push the epidermis upward, lifting it away from the column, opening the pore and allowing conidia to emerge. The conidioma is regarded as a modified acervulus.

An apothecial discomycete from diseased branches of Japanese red pine in Georgia was found to be conspecific with Cenangium atropurpureum. After comparison of the Georgia material with Ce. ferruginosum, the type species, it was concluded that on the basis of ectal excipular characteristics, Ce. atropurpureum is better accommodated in Crumenulopsis. This species differs from European species of Crumenulopsis in the oval shape of the ascospore, presence of a gelatinous ascospore sheath, and possession of a diffusible purplish pigment in KOH. It differs from the Florida species, Cr. lacrimiformia, in the shape of the ascospore and ascospore sheath, larger size of the ascoma, presence of the purple pigment, and host species.

The mode of penetration and infection of the peanut leaf by Leptosphaerulina crassiasca were studied by means of light and electron microscopy. The attachment of the multicellular ascospores to the leaf surface was by a mucilagenous sheath that covered the ascospores at maturity. This sheath expanded rapidly in moisture and it extended along the germ tube as it elongated. Two types of germ tubes appeared to be formed, a short one and a relatively long one. Short germ tubes were not delimited by septa, and they penetrated the cuticle and host epidermal cell wall directly without appressorium formation. Penetration occurred 2–6 h after inoculation. The wall was breached by a relatively broad infection hypha that expanded in width inside the host cell wall. The lack of mechanical rupture at the infection site indicated that penetration may involve enzymatic activity. Intracellular hyphae were present in the epidermal cells, but only intercellular hyphae occurred in the palisade and spongy mesophyll tissues. The intercellular hyphae were frequently appressed to the outer surface of the host cell wall. Infected areas rarely exceeded 1 mm in diameter, and they were only sparsely colonized by hyphae of the pathogen. Host cells in the vicinity of hyphae underwent senescence and death. One to 2 months after inoculation, pseudothecia formed in the dead tissues of detached leaves. In some instances the presence of penetration hyphae by short germ tubes induced the formation of a papilla inside the host cell wall, which either restricted growth of the infection hypha or resulted in the death of the germ tube and the cell from which it arose. Long germ tubes were delimited by simple septa and they terminated in an appressorium; however, details of their behavior were not studied. Key words: Arachis hypogaea, Ascomycotina, Dothideales, leaf scorch, pepper spot.

Cultures of Leptosphaerulina crassiasca from single ascospores formed ascostromata, indicating that the fungus is homothallic. Mycelial hyphae were septate, with uninucleate cells, and they gave ri...

Muscodor yucatanensis, an endophytic fungus, was isolated from the leaves of Bursera simaruba (Burseraceae) in a dry, semideciduous tropical forest in the Ecological Reserve El Eden, Quintana Roo, Mexico. We tested the mixture of volatile organic compounds (VOCs) produced by M. yucatanensis for allelochemical effects against other endophytic fungi, phytopathogenic fungi and fungoids, and plants. VOCs were lethal to Guignardia mangifera, Colletotrichum sp., Phomopsis sp., Alternaria solani, Rhizoctonia sp., Phytophthora capsici, and P. parasitica, but had no effect on Fusarium oxysporum, Xylaria sp., the endophytic isolate 120, or M. yucatanensis. VOCs inhibited root elongation in amaranth, tomato, and barnyard grass, particularly those produced during the first 15 days of fungal growth. VOCs were identified by gas chromatography/mass spectrometry and included compounds not previously reported from other Muscodor species and the previously reported compounds octane, 2-methyl butyl acetate, 2-pentyl furan, caryophyllene, and aromadendrene. We also evaluated organic extracts from the culture medium and mycelium of M. yucatanensis on the same endophytes, phytopathogens, and plants. In general, extracts inhibited plants more than endophytic or phytopathogens fungi. G. mangifera was the only organism that was significantly stimulated by both extracts regardless of concentration. Compounds in both organic extracts were identified by gas chromatography/mass spectrometry. We discuss the possible allelopathic role that metabolites of M. yucatanensis play in its ecological interactions with its host plant and other organisms.

Periconia variicolor was isolated from water of an evaporation pond used for salt production on the southwestern coast of Puerto Rico. On the basis of cultural and morphological characteristics and ITS sequence it is describe as a new species of Periconia.

Chemical investigation of the mycelium of Edenia gomezpompae, a newly discovered endophytic fungus isolated from the leaves of Callicarpa acuminata (Verbenaceae) collected from the ecological reserve El Eden, Quintana Roo, Mexico, resulted in the isolation of four naphthoquinone spiroketals, including three new compounds and palmarumycin CP2 (4). We elucidated the structures of the metabolites by extensive NMR spectroscopy studies, including DEPT, COSY, NOESY, HSQC, HMBC, and chiroptical methods. The trivial names proposed for these compounds are preussomerin EG1 (1), preussomerin EG2 (2) and preussomerin EG3 (3). In addition, the X-ray data for 4 were obtained. The bioactivity of the mycelial organic extracts and the pure compounds was tested against three endophytic fungi (Colletotrichum sp., Phomopsis sp., and Guignardia manguifera) isolated from the same plant species (C. acuminata, Verbenaceae) and against four economically important phytopathogenic microorganisms (two fungoid oomycetes, Phythophtora capsici and Phythophtora parasitica, and the fungi Fusarium oxysporum and Alternaria solani). Spiroketals 1-3 displayed significant growth inhibition against all the phytopathogens. IC50 values for the four phytopathogens were from 20 to 170 microg/ml. Palmarumycin CP2 (4) was not bioactive against any of the fungi tested. Compound 1 showed the strongest bioactivity. The acetylated derivatives of preussomerin EG1 (1), 1a and 1b, were obtained and their biological activity was tested on endophytes and phytopathogens. Preussomerin EG1 1, 1a and 1b exhibited significant bioactivity against all microorganisms tested with the exception of Alternaria solani. This is the first report of allelochemicals with antifungal activity from the newly discovered endophytic fungus E. gomezpompae.

Acremonium is generally considered to be a highly polyphyletic form genus containing distantly related fungi. Sectional divisions within Acremonium distinguish the clavicipitaceous grass endophytes of sect. Albolanosa from the generally saprobic species of sections Acremonium, Chaetomioides, Gliomastix, and Nectrioidea. In an effort to assess the possible number of lineages currently placed within Acremon- ium and to determine which groups of sexual asco- mycetes are phylogenetically affiliated with Acremon- ium species, maximum parsimony and neighborjoin- ing analyses were performed using partial sequences of the nuclear small subunit ribosomal DNA (18S rDNA). Acremonium was shown to be a polyphyletic taon with affiliations to at least three ascomycetous orders: 1) most of the examined species from the sections Acremonium, Gliomastix, and Nectrioidea showed a relationship to the Hypocreaceae even though many of these species have never been asso- ciated with any teleomorph; 2) the grass endophytes of sect. Albolanosa and other taxa from the Clavicip- itaceae formed a monophyletic group derived from within the Hypocreales; 3) the thermophilic A. ala- bamense of sect. Chaetomioides was derived from with- in the Sordariales. Acremonium alternatum, the tye species of the genus, was one of the species showing affiliation to the Hypocreaceae. In order to eliminate some of the heterogeneity within Acremonium while also emphasizing the unique biological, morpholog- ical, and ecological characteristics of the grass en do