Showing papers in "Mycologia in 1984"
TL;DR: Conference sur les affinites entre les Champignons Secotioides et les Agaricaceae et leurs voies evolutives.
Abstract: Conference sur les affinites entre les Champignons Secotioides et les Agaricaceae et leurs voies evolutives
145 citations
127 citations
TL;DR: Vesicular-arbuscular (VA) mycorrhizal fungi were collected and identified from saline locations throughout southern and central California and Nevada as mentioned in this paper, from which 38 soil samples containing VA mycophyllous fungi from 22 plant species were used to inoculate tomato seedlings and evaluate their growth under artificial salinization.
Abstract: Vesicular-arbuscular (VA) mycorrhizal fungi were collected and identified from saline locations throughout southern and central California and Nevada. From this collection, 38 soil samples containing VA mycorrhizal fungi from 22 plant species were used to inoculate tomato seedlings and evaluate their growth under artificial salinization. Six samples significantly improved growth of tomato in salinized soil when compared to a salinized, nonmycorrhizal control. Growth with 14 samples in salinized soil was as good as growth of a nonmycorrhizal control in nonsalinized soil. Glomusfasciculatum consistently provided the largest growth response. Negative correlations were found between the amount of mycorrhizal colonization on tomato roots in the greenhouse and electrical conductivity, Na concentration, and osmotic potential of the saline soil samples from the field. The amount of mycorrhizal colonization on hosts in the field from which the soil samples were collected was not correlated to growth response or mycorrhizal colonization of tomato in the greenhouse.
123 citations
TL;DR: In the Ceratocystis complex the genus Ophiostoma is maintained for species which have conidial anamorphs other than Chalara, have rhamnose in their cell walls, and are resistant to cycloheximide.
Abstract: In the Ceratocystis complex the genus Ophiostoma is maintained for species which have conidial anamorphs other than Chalara, have rhamnose in their cell walls, and are resistant to cycloheximide. F...
117 citations
TL;DR: The influence of vesicular-arbuscular mycorrhizae on the water relations of the rangeland grass Agropyron smithii was compared and changes in xylem pressure potentials over a soil water potential range from 0 to -6 MPa were not statistically different between plants infected with the two fungal congeners.
Abstract: The influence of vesicular-arbuscular mycorrhizae on the water relations of the rangeland grass Agropyron smithii was compared for two different geographic isolates of both Glomus macrocarpum var. macrocarpum and G. microcarpum. Spores of these fungi were collected from two sites in Wyoming that differed in total annual precipitation and were used to inoculate greenhouse-grown plants. Leaf resistances to water vapor loss (R^) were about 11% lower in all mycorrhizal vs. nonmycorrhizal plants at high soil and plant water potentials (>-0.2 MPa) and up to 47% lower at soil and plant water potentials near -6 MPa. Plants infected with G. microcarpum had R^ values that were up to 26% lower (1520 vs. 1120 m s_1) than G. macrocarpum-infected plants at the lowest xylem pressure potentials. However, changes in xylem pressure potentials over a soil water potential range from 0 to -6 MPa were not statistically different between plants infected with the two fungal congeners. Plants infected with G. microcarpum from the dry Wyoming site had statistically different responses to drying soil than did plants infected with G. microcarpum collected from the more mesic site with an approximate 9% difference in R^ (1120 m s~l vs. 1220 m s~*) at a xylem pressure potential near - 6 MPa. As was the case for the fungal congeners, xylem pressure potentials of the host A. smithii did not differ between the two G. microcarpum isolates over the range of soil drying.
103 citations
TL;DR: It is proposed that the ambiguous and inappropriate term "sclerotic cells" be replaced by the more appropriate term "muriform cells" to describe precisely the tissue form of the causal agents of chromoblastomycosis.
Abstract: We studied critically 26 isolates that had been called Wangiella dermatitidis (including Kano's type culture) and were variously described in the literature as causal agents of chromoblastomycosis, chromomycosis, or phaeohyphomycosis. Only 21 ofthe 26 proved to be W. dermatitidis, on the basis of colonial and microscopic morphology, thermotolerance, decomposition of tyrosine, and exoantigen tests. Eighteen of the 21 confirmed isolates were from Japan, two from Taiwan, and one from the U.S. The remaining five isolates were identified as Exophiala jeanselmei (2), E. moniliae (2), and Fonsecaea pedrosoi (1). We also reviewed the clinical aspects of the infections, their treatment, and the histopathologic appearance of the etiologic agents in 21 cases of phaeohyphomycosis. Wangiella dermatitidis should be recognized as a dermatotropic as well as a neurotropic agent among the pathogenic dematiaceous Hyphomycetes. The high case-fatality rate (48%) caused by W. dermatitidis clearly emphasizes that this mould is an important agent of systemic phaeohyphomycosis with a marked tendency to invade the central nervous system. In the case reports, the indiscriminate use ofthe term "sclerotic cells" to describe the tissue forms of these fungi was not in accord with their true nature. In tissue they developed dark-walled mycelium, spherical cells, with or without buds or toruloid hyphae, either alone or in various combinations. The absence of muriform cells clearly showed that the patients had developed phaeohyphomycosis, not chromoblastomycosis. We propose that the ambiguous and inappropriate term "sclerotic cells" be replaced by the more appropriate term "muriform cells" to describe precisely the tissue form of the causal agents of chromoblastomycosis.
90 citations
TL;DR: Six new species of Endogonaceae are described, including an unusual species that forms chlamydospores and thin-walled accessory cells similar to those formed by species in the genus Glomus.
Abstract: Six new species of Endogonaceae are described, Acaulospora appendicula, A. longula, A. mellea, A. morrowae, Glomus manihotis, and Entrophospora colombiana. Acaulospora ap? pendicula is an unusual species that forms chlamydospores and thin-walled accessory cells similar to those formed by species in the genus Glomus. In addition, observations on the occurrence of Acaulospora foveata in Colombia and some characteristics of this fungus not included in the original description are presented. A dichotomous key to all described species of Acaulospora is presented.
74 citations
TL;DR: The carbonicolous discomycete, Sphaerosporella brunnea, formed ectomycorrhizae with jack pine (Pinus banksiana) in monoxenic cultures and in open containers to determine the degree of host specificity and to develop criteria for the identification of S. brunnea in culture and in the myCorrhizal state.
Abstract: The carbonicolous discomycete, Sphaerosporella brunnea, formed ectomycorrhizae with jack pine (Pinus banksiana) in monoxenic cultures and in open containers. In addition, mycorrhizae were formed with species of Picea, Larix, and Populus. The mycorrhizae were characterized by thin mantles and large diameter hyphal cells with Woronin bodies at the septa. Sphaerosporella brunnea is unusual as a mycorrhizal symbiont due to its taxonomic position, carbonicolous nature, very rapid growth rate, and ease of ascospore germination. A small discomycete, Sphaerosporella brunnea (Alb. & Schw.: Fr.) Svrcek & Kubicka, fruited prolifically on the peat growing medium during mycorrhizal inoculation trials of containerized jack pine {Pinus banksiana Lamb.) seedlings. Ascospores ejected onto agar germinated readily and colony growth was rapid. Examination ofthe root systems showed that a high percentage ofthe short roots of jack pine were infected with a fungus apparently indigenous to peat rather than with the introduced symbionts. The mycorrhizae formed by the indigenous fungus were characterized by poorly developed mantles and large diameter hyphae. Cul? tures identical to those originating from S. brunnea ascospores were obtained from a few of these mycorrhizae. Since Discomycetes were not known to form ectomycorrhizae, it was of interest to test the effect of S. brunnea on the root system of jack pine. The objectives of this study were to (1) determine if S. brunnea was capable of forming ectomycorrhizae with jack pine under monoxenic conditions and in open containers, (2) to determine the degree of host specificity if it did form ectomycorrhizae, (3) develop criteria for the identification of S. brunnea in culture and in the mycorrhizal state, and (4) determine if fungi closely related to Sphae? rosporella could form mycorrhizae with jack pine. MATERIALS AND METHODS Pure culture syntheses were conducted to determine mycorrhizal potential with jack pine and to determine host specificity. The traditional combination of peat and vermiculite (Marx and Zak, 1965) was used at a ratio of 1:15 (v/v). The nutrient solution consisted of 0.13 g (NH4)2HP04, 0.5 g NH4C1, 0.44 g Ca(N03)2 ? 4H20, 0.45 g KC1, 0.5 g MgS04-7H20, 2.5 g dextrose, 2.5 g malt extract, 100 Mg thiamine, 0.048 g sequestrene and 1 ml micronutrient stock (Arnon, 1938) per liter distilled water. The nutrient solution was added to quart jars (150 ml/400 ml peat-vermiculite) and autoclaved at 121 C for 15 min. Seeds were surfacesterilized in 30% H202 for 30 min, plated on PDA and one uncontaminated germinant was added to each jar. Simultaneously, about 30 ml of a mycelial slurry made from colonies on MMN agar (Marx, 1969) was added to each jar. The jars were incubated for 3 to 4 months in a growth chamber with a 16-h day. Substrate
70 citations
TL;DR: In this article, the authors analyzed the structure of meiosis and the spindle pole body cycle in Ustilago maydis by three-dimensional reconstructions from serial sections of preselected sta...
Abstract: Ultrastructure of meiosis and the spindle pole body cycle in Ustilago maydis (Basidiomycota, Ustilaginales) was analyzed by three-dimensional reconstructions from serial sections of preselected sta...
TL;DR: The synthesis of carotenoid pigments by Wangiella dermatitidis was demonstrated with both wild-type (wt) and melanin-deficient (Mel~) strains and their syntheses were shown to require photoinduction.
Abstract: The synthesis of carotenoid pigments by Wangiella dermatitidis was demonstrated with both wild-type (wt) and melanin-deficient (Mel~) strains. The carotenoids synthesized included torulene and torularhodin and their syntheses were shown to require photoinduction. Illuminated incubation of a Mel~ strain provided carotenoid-pigmented cells which were more resistant to ultraviolet irradiation than dark-incubated, nonpigmented cells. Both the wt and Mel" strains were capable of photoreactivation following exposure to ultraviolet light. These data describe the first observation of carotenoid synthesis by one ofthe dematiaceous yeasts and suggest that these pigments may have some role in photoprotection. Carotenoids are polyisoprenoid compounds responsible for the pigmentation of a number of fungi, including the red yeasts of the form-genus Rhodotorula (Goodwin, 1972; Simpson et al, 1964) and their perfect forms as the basidiomycetous teliomorphs of the genus Rhodosporidium (Kockova-Kratochvilova and Bystricky, 1974). The fungal form-family Dematiaceae is characterized by the production of dark pigments associated with the cell wall (Ainsworth, 1971), but carotenoid production has been demonstrated in only two dematiaceous molds, Epicoccum nigrum Link ex Fr. (Gribanovski-Sassu and Foppen, 1969) and Alternaria alternata (Fries) Keissler (Haggblom and Unestam, 1979), and in none of the black yeasts. The human pathogen, Wangiella dermatitidis (Kano) McGinnis (McGinnis, 1977'a, b) is a polymorphic, dematiaceous fungus which grows in vitro primarily as a yeast, but may also produce hyphal or multicellular morphologies (Szaniszlo et al, 1981). Like other dematiaceous fungi, this organism produces a darklypigmented cell wall. Melanin synthesis within the cell wall is responsible for the dark pigmentation (Geis and Szaniszlo, unpublished observation). The purpose of this communication is to report the isolation and identification of carotenoid pigments from yeast cells of W. dermatitidis and to demonstrate the potential role of these pigments in photoprotection.
TL;DR: Data from sexual incompatibility and cultural studies were used to further elucidate the biology and taxonomy of species of Laccaria and showed a bifactorial (tetrapolar) incompatibility system for three species.
Abstract: Data from sexual incompatibility and cultural studies were used to further elucidate the biology and taxonomy of species of Laccaria. Six intersterility groups, representing five species, were recorded in 47 Swedish collections by pairing tests among monosporous isolates. In the secondarily homothallic L. altaica the pairings were made with monokaryotic mycelia produced by dedikaryotization. Laccaria altaica, L. amethystina, L. bicolor, and L. proxima each comprised one intersterility group, while members of two groups were referable to L. laccata sensu stricto. Intrastock pairing tests with three species showed a bifactorial (tetrapolar) incompatibility system. In only three of 11 cases analyzed, however, were all four mating type factors found. Each of the species could be further characterized by their growth rate, cultural morphology, and early growth pattern of the primary mycelium. Nutritional tests showed no differences in vitamin requirements for the five species studied. However, L. bicolor responded differently to some complex additives.
TL;DR: It is hypothesized that small-scale perturbations (erosion, gopher and ant mounds) following the major volcanic disturbance may drive succession by exposing buried mycorrhizal and decomposer fungi.
Abstract: The 18 May 1980 eruption of Mount St. Helens resulted in the burial of relatively well developed soils under variable depths of sterile tephra and ash. During summer 1982, we examined a series of sites and estimated the numbers of spores of Endogonaceae that had been transported from the buried soil to the new ground surface by either abiotic or biotic vectors. There was no difference between spore counts of Endogone spp. or Glomus spp. in the buried soils of forests and clear-cuts; spores were rare in the tephra at any site. In areas featuring less than or equal to 50 cm of tephra, spores were transported to the surface by gophers (in previous clear-cut areas) and by ants (in previous forest and clear-cut habitats). In the Pumice Plain, an area devoid of gophers and ants, erosion exposed spores to the surface. We found no evidence to suggest that endogonaceous fungi grow back up root systems from buried horizons. We hypothesize that small-scale perturbations (erosion, gopher and ant mounds) following the major volcanic disturbance may drive succession by exposing buried mycorrhizal and decomposer fungi. 26 references, 2 figures, 3 tables.
TL;DR: The nuclear and spindle pole body cycles of U. maydis support the inclusion of the Ustilaginales in the Basidiomycetes, and these features are similar to those reported for the heterobasidiomyCetous yeasts.
Abstract: Postmeiotic mitosis, basidiospore development and metabasidial septation are analyzed ultrastructurally in Ustilago maydis (Basidiomycota, Ustilaginales). The spindle pole body at mitotic prophase is composed of two globular elements connected by a middle piece. During the transition from interphase II to mitotic prophase the globular elements enlarge, the middle piece elongates, and the spindle pole body typically moves to an apical position on the migratory nucleus. Cytoplasmic microtubules are associated with organelle movement into the basidiospore. Sterigmata arise endogenously. Mitotic nuclei divide into a spindlecontaining portion which moves into the basidiospore and a nucleolar portion which degenerates in the metabasidium. One postmitotic sibling nucleus remains in the basidiospore while the other returns to the metabasidium. Primary metabasidial and sterigmal septa are traversed by a simple, eccentric to centric pore that may become walled-off. Complete, adventitious metabasidial septa result in the formation of fragmentation zones. The nuclear and spindle pole body cycles of U. maydis support the inclusion of the Ustilaginales in the Basidiomycetes, and these features are similar to those reported for the heterobasidiomycetous yeasts.
TL;DR: On examine les comportements alimentaires de Sciurus aberti vivant dans les forets de P. ponderosa et verifie si les spores des champignons peuvent rester viables apres passage dans le tube digestif.
Abstract: On examine les comportements alimentaires de Sciurus aberti vivant dans les forets de P. ponderosa. On verifie si les spores des champignons peuvent rester viables apres passage dans le tube digestif et si les ecureuils peuvent servir de vecteurs pour les champignons ectomycorhiziens
TL;DR: The dynamics of aspen leaf degradation caused by six species of aquatic Hyphomycetes are followed and the effect of fungal modification of leaves on feeding responses of caddisfly is examined.
Abstract: We followed the dynamics of aspen leaf degradation caused by six species of aquatic Hyphomycetes and examined the effect of fungal modification of leaves on feeding responses of caddisfly (...
TL;DR: It is concluded that teleomorphic and anamorphic isolates from stem cankers and blighted tops of soybean should be provisionally called D. phaseolorum f.
Abstract: Phomopsis batatae, P. phaseoli, and P. sojae were able to infect, without production of obvious symptoms, seedlings of sweet potato and of 16 legumes inoculated in the greenhouse. These fungi produced pycnidia on inoculated seedlings incubated in laboratory moist chambers. Under conditions of natural infection in the field, P. sojae was recovered from stems of 14 of 21 legumes. This fungus was also isolated from seeds of cowpea and lima bean as well as from soybean, its usual host. The interpretation of these results questions the validity of regarding these anamorphs as three distinct species. Taken with the close similarity in morphology reported for these taxa in the literature and observed in my own isolates and in herbarium specimens, I conclude that these taxa are all one species, the valid name of which is Phomopsis phaseoli (Desm.) Sacc. For similar reasons, I consider the teleomorphs Diaporthe phaseolorum var. batatatis, var. phaseolorum, and var. sojae to be one and the same taxon, D. phaseolorum (Cooke & Ellis) Sacc. I believe that teleomorphic and anamorphic isolates from stem cankers and blighted tops of soybean should be provisionally called D. phaseolorum f. sp. caulivora and P. phaseoli f. sp. caulivora, respectively, until it can be demonstrated by a non-wounding technique that they can cause these pathological conditions when re-introduced into the host.
TL;DR: An antibody “double sandwich” enzyme immunoassay demonstrated quantitative differences in the numbers of certain monoclonal antibody binding sites of the two fungi, although these differences did not provide a basis for the unambiguous detection of either bunt species in contaminated wheat shipments.
Abstract: Immunologic analyses of teliospore surfaces using polyclonal antisera and monoclonal antibodies indicated that Tilletia controversa and Tilletia caries were very similar. Although two polysaccharid...
TL;DR: An electron microscopic study revealed the unwalled, multinucleate thallus of the endoparasite in prosporangia and sporangia of P. euglenae where the plasma membrane of the ENDO?
Abstract: The endoparasitic chytrid, Rozella polyphagi, was found infecting another chytrid, Polyphagus euglenae, which is itself an epiparasite ofEuglena viridis and E. gracilis. An electron microscopic study revealed the unwalled, multinucleate thallus of the endoparasite in prosporangia and sporangia of P. euglenae where the plasma membrane of the endoparasitic thallus was in direct contact with the cytoplasm of P. euglenae. Profiles of degenerating host mitochondria in vacuoles of the endoparasite and of cytoplasmic projections of the endo? parasite around portions of host cytoplasm suggest that the endoparasite phagocytizes host protoplasm. A discussion of interfaces between unwalled endoparasites and their hosts show that the absence of host enveloping membranes around endoparasites and the capability of endoparasites to phagocytize host cytoplasm is more common than generally recognized.
TL;DR: Microscopie optique et electronique a balayage de 2 types de conidiogenese et de the variabilite des conidiomata dans un but systematique.
Abstract: Microscopie optique et electronique a balayage de 2 types de conidiogenese et de la variabilite des conidiomata dans un but systematique
TL;DR: Etude sur ble tendre (cv Newton) et sur trefle violet (cv Kenstar) en culture en pots sur limon sableux sterilise, de l'influence des basses temperatures (10 a 25°C) sur la colonisation mycorhizienne par Glomus mosseae.
Abstract: Etude sur ble tendre (cv. Newton) et sur trefle violet (cv. Kenstar) en culture en pots sur limon sableux sterilise, de l'influence des basses temperatures (10 a 25°C) sur la colonisation mycorhizienne par Glomus mosseae
TL;DR: The lipid, fatty acids, and sterol content of a pure preparation of the intramatrical vesicles of a Glomus sp.
Abstract: The lipid, fatty acids, and sterol content of a pure preparation ofthe intramatrical vesicles of a Glomus sp. were determined. Lipid content of vesicles was 58.2% ofthe dry mass. The predominant lipid fraction was glycolipid and sphingolipid (44.5% of total lipid) followed by neutral lipid (25.5%) and phospholipid (24.2%). The fatty acids were examined by gas liquid chromatography. While 16:1 fatty acid was exceptionally high in the neutral and glycolipid fraction (60% and 51.2% ofthe total fatty acids), 18:2 was the predominant fatty acid in the phospholipid fraction (70.9%). The sterol content ofthe intramatrical vesicles was 5.8% of the spore dry mass (11.3% of total lipid). These results are compared to other lipid information available on the VAM and other fungi.
TL;DR: A defined medium that would support abundant OA production without affecting mycelial growth would greatly facilitate studies on factors regulating OAproduction in S. rolfsii.
Abstract: Several fungi produce oxalic acid (OA) during growth in liquid culture (2, 8, 9). In the plant pathogenic fungus Sclerotium rolfsii Sacc. [teleomorph: Athelia rolfsii (Curzi) Tu and Kimbrough] (13), OA is a product ofthe glyoxylate bypass ofthe tricarboxylic acid cycle (7). Production of OA in plant tissues was reported to facilitate infection by the fungus and enhance disease development (1, 3, 5). In a study by Higgins (3), some factors influencing OA production by S. rolfsii in culture media were described. Maxwell and Bateman (6) investigated the effect of selected carbon sources and pH on OA production. Although S. rolfsii can utilize numerous carbon sources for growth (4), abundant mycelial growth does not insure high OA production (1, 6). The standard liquid basal salts medium (LSM) for growth of S. rolfsii contains the following: K2HP04, 0.7 g; KC1, 0.15 g; MgS04-7H20, 0.4 g; ZnS04 7H20, 12 mg; MnS04H20, 14 mg; FeCl3H20, 14 mg; thiamine HC1, 1 mg; distilled water, 1 liter (6). Dextrose (19.8 g/1) and NH4N03 (1 g/1) are added to provide the carbon and nitrogen sources, respectively. While this complete medium (C-LSM) supports good mycelial growth, OA production is negligible (6). A defined medium that would support abundant OA production without affecting mycelial growth would greatly facilitate studies on factors regulating OA production in S. rolfsii. The objective of this study was to define the constituents of such a medium. The following additions to LSM were tested: a) carbon sources (with NH4N03 as the nitrogen source)?19.8 g/1 dextrose, potato starch, citrus pectin, carboxymethylcellulose (CMC), peptone, or Na salts of succinate, citrate, and acetate; b) mixtures of carbon sources?9.9 g/1 dextrose mixed with 9.9 g/1 pectin, CMC, yeast extract, peptone, or with 20 g/1 Na succinate (0.074 m), 16.2 g/1 Na citrate (0.055 m), or citric acid-tris buffer (0.1 m, pH 6); c) inorganic nitrogen sources (with dextrose as the carbon source)?NH4N03, NH4H2P04, Ca(N03)2, (NH4)2S04, NH4C1, NaN03, KN03, and urea, all tested at a nitrogen level equivalent to that in 1 g/1 NH4N03 (12.5 mM of N); d) organic nitrogen sources?DL-asparagine, L-arginine, DL-threonine, DL-tryptophan, DL-phenylalanine, DL-leucine, L-alanine, and L-histidine, all tested at a N level of 12.5 mM; or 0.1% yeast extract; e) buffersC-LSM was buffered at pH values ranging from 2.1 to 6.9 with 0.1 m citric acidtris or at pH 5 with 12.5 mM KH2P04. Isolate 1132-8 of S. rolfsii from bentgrass was used throughout this study. Six additional isolates (1094, 1126, 2672, 2394, 2823, 3078), described in detail elsewhere (13), were grown in C-LSM to compare differences among isolates in dry weight (DW) and OA production. Each carbon and nitrogen source (in distilled water) was sterilized separately by autoclaving at 121 C for 15 min or by passage through a 0.45 p,m Millipore filter before mixing aseptically with cooled, autoclaved, double-strength LSM. The pH was adjusted to 5.7-5.8 with sterile 1 n NaOH or HC1. The media were dispensed in 30 ml aliquots into 125 ml Erlenmeyer flasks. Each flask was in-
TL;DR: Increases in spore population densities during thegrowing season and measurements of viable mycorrhizal fungus propagules by the Most Probable Number technique at the end of the growing season demonstrated that either soil fumigation did not kill all propagules or the fungi were reintroduced.
Abstract: Field experiments were conducted to determine the effects of fallow, growing pepper, tomato, or the green manure crop sorghum-sudangrass on spore population densities of mycorrhizal fungi. Two crops, pepper and tomato, were grown in soil either fumigated or not with 67% methyl bromide-33% chloropicrin. Glomus macrocarpum comprised over half the total spore population. Spores of G. microcarpum, G. constrictum, and G. caledonium were next most prevalent. Spores or sporocarps of G. fasciculatum, four species of Acaulospora, two of Gigaspora, and Sclerocystis sinuosa occurred sporadically or in low numbers. Growing sorghum-sudangrass, tomato, and pepper (except in nonfumigated soil) increased total spores/kg soil, while fallow reduced them. Populations of Glomus caledonium spores increased 40-fold with sorghum-sudangrass. Populations of spores of G. macrocarpum (except in nonfumigated pepper plots) and G. microcarpum were less with fallow than with any of the crops at the end of the season. Twelve days after fumigation, spores of mycorrhizal fungi were still present but in reduced numbers. Increases in spore population densities during the growing season and measurements of viable mycorrhizal fungus propagules by the Most Probable Number technique at the end of the growing season demonstrated that either soil fumigation did not kill all propagules or the fungi were reintroduced.
TL;DR: In a simple laboratory model system, the influence of temperature on the ability of 5 sympatric species of Trichoderma to compete for spruce litter was studied.
Abstract: In a simple laboratory model system, the influence of temperature on the ability of 5 sympatric species of Trichoderma to compete for spruce litter (Picea abies) was studied. At temperatures of 5 C...
TL;DR: The relationships among nine different isolates of Penicillium crustosum were studied by pyrolysis-gas chromatography coupled with a pattern recognition analysis (PR), and the results obtained were compared to mycotoxin production profiles of the isolates.
Abstract: The relationships among nine different isolates of Penicillium crustosum were studied by pyrolysis-gas chromatography (Py-GC) coupled with a pattern recognition analysis (PR). The results obtained were compared to mycotoxin production profiles of the isolates. Based on the Py-GC analyses the isolates could be divided into two well-differentiated groups, and one of these groups could be further subdivided. Based on mycotoxin analyses the isolates could be divided into three groups: one group (P. crustosum sensu stricto) in which the fungi produced penitrem A, roquefortine C, and terrestric acid, one group ("P. caseiphilum" = P. camembertii group II) producing cyclopiazonic acid, and a third group ("P. melanochlorum" = P. mali) with isolates producing none of these toxins. Basically, the Py-GC-PR grouping agreed with the mycotoxin profile grouping, although the agreement was not perfect. The taxonomic treatment of these strains as one species thus seems unsatisfactory. The Py-GC-PR method appears to be quite useful as one aid in establishing criteria for studies of relationships between related fungi. (Less)
TL;DR: Plant regulation of mechanisms for parasitism in fungi shows that to survive the selection pressure of evolution, it is also likely that disease resistance in plants depends upon the activation of multicomponent mechanisms for resistance.
Abstract: We share this world with a myriad of living organisms each equally well adjusted for survival in its ecological niche. We constantly interact with each other either directly or indirectly and in the overall scheme of life this interaction results in survival. Life, nevertheless, is not free of disease. Disease implies a harmful effect on the life processes of an organism, but a harmful effect on one organism may be beneficial to another. Disease may limit realization ofthe genetic potential for yield and quality in agricultural crops, but in nature it is seldom the determinant of survival for both plant and pathogen. With a different perspective, the title of this article could be plant regulation of mechanisms for parasitism in fungi. Specificity of a pathogen for a plant is as complex and important a phenomenon as is the specificity of host reaction to a pathogen. It is difficult to imagine two organisms in close association, as would be the case of a fungus which penetrated into the tissues of a green plant, without an interaction and influence on the growth and development of each. It is an apparent paradox, therefore, that in successful parasitism, the compatibility ofthe host and pathogen is frequently prolonged, at least during initial stages of the parasite's development. As would be expected, the highly attuned metabolism of host and parasite is rarely encountered. Resistance is the common phenomenon in nature and susceptibility is the rare exception. A critical consideration in the health of a plant or development of a parasite would be the rapid recognition of its partner as non-self. From our perspective we often are most concerned with the plant recognizing the pathogen as non-self and reacting to restrict its development. The recognition of the plant as non-self by the pathogen may, however, be of importance in determining the success of the pathogen. The longer the pathogen avoids or suppresses recognition by the host, the more likely the pathogen will develop and reproduce within the host. Having recognized the pathogen as non-self, the plant activates metabolic pro? cesses which may restrict the pathogen's development. In turn, the pathogen can suppress such processes or detoxicate its products. The speed and magnitude with which the plant activates its mechanisms for disease resistance are critical to the development of the pathogen. To survive the selection pressure of evolution, it is also likely that disease resistance in plants depends upon the activation of multicomponent mechanisms for resistance. A single mechanism or compound with a single metabolic site of
TL;DR: Aspergillus flavus was introduced into several natural openings in cotton plants at or before anthesis and the subsequent infection rate in the mature seed determined, and seeds from plants inoculated at the cotyledonary node, involucral nectaries, and flower buds had significantly higher infection rates than uninoculated control plants.
Abstract: Aspergillus flavus was introduced into several natural openings in cotton plants at or before anthesis and the subsequent infection rate in the mature seed determined. Cotyledonary leaf scars of seedlings, unopened flower buds, and involucral nectaries or stigmata of newly opened flowers were inoculated with dry fungal spores. Seeds from plants inoculated at the cotyledonary node, involucral nectaries, and flower buds had significantly higher A. flavus infection rates than uninoculated control plants.
TL;DR: Biological, taxonomic, and nomenclatural aspects of Xylaria cubensis, X. allantoidea, and X. poitei are discussed, with particular reference to their occurrence and activities in continental United States.
Abstract: Biological, taxonomic, and nomenclatural aspects of Xylaria cubensis, X. allantoidea, and X. poitei are discussed, with particular reference to their occurrence and activities in continental United...