Showing papers in "Transactions of The British Mycological Society in 1988"
TL;DR: It was concluded that conidial wall texture was the most effective criterion for distinguishing A. flavus and A. parasiticus; therefore, a combination of characters was necessary to separate these two species.
Abstract: More than 150 isolates of Aspergillus flavus, A. oryzae, A. parasiticus, A. sojae and A. tamarii from collections around the world were examined independently in two laboratories as unknowns, and data assessed to evaluate a wide range of morphological characters for suitability as taxonomic criteria. Mycotoxin production was also assessed. It was concluded that conidial wall texture was the most effective criterion for distinguishing A. flavus and A. parasiticus. A. flavus has a broad interface with VA. oryzae; therefore, a combination of characters was necessary to separate these two species. Mycotoxin production correlated well with morphological speciation. Only A. flavus and A. parasiticus isolates produced B aflatoxins. Very few A. flavus isolates produced G aflatoxins whereas almost all A. parasiticus isolates did. The A. parasiticus isolates never produced cyclopiazonic acid, but some isolates of A. flavus, A. tamarii and A. oryzae did.
300 citations
TL;DR: A cluster analysis showed that Pinus tissues can be separated from Fagus tissues on the basis of their endophyte populations, and a K-means cluster analysis revealed that eleven of the fungi isolated were mainly responsible for this separation.
Abstract: Fifty-three endophytes were isolated from whole stem and xylem tissues taken from a mixed stand of Pinus sylvestris and Fagus sylvatica. Rhinocladiella atrovirens appeared confined to the xylem of Fagus, Coniothyrium cf, pini to the xylem of Pinus. Coryneum betulinum, Cryptocline sp. 1 and 2, Cylindrocarpon album and Melanconium atrum occurred in whole stems of Fagus only, Coniochaeta tetraspora and Sporormiella australis in whole stems of Pinus. Five species were non-host specific and occurred in all four morphological units. A cluster analysis showed that Pinus tissues can be separated from Fagus tissues on the basis of their endophyte populations, and a K-means cluster analysis revealed that eleven of the fungi isolated were mainly responsible for this separation. A discriminant analysis performed with these fungi demonstrated good discrimination between the four tissue sample groups.
153 citations
TL;DR: Changes in this century in the composition of the macromycete flora in the Netherlands were studied by a comparison of excursion reports, mapping of selected species, and repeated mycocoenological studies in permanent plots in forests, and two hypotheses that may explain this phenomenon are discussed.
Abstract: Changes in this century in the composition of the macromycete flora in the Netherlands were studied by a comparison of excursion reports, mapping of selected species, and repeated mycocoenological studies in permanent plots in forests. The three approaches show similar trends. Among saprotrophic macromycetes of forest litter only a few species show a significant increase or decrease, but most saprotrophic species of grass- and heath-lands are markedly decreasing, due to modern agricultural practice, notably the use of artificial fertilizers. Lignicolous macromycetes are in general increasing, in particular parasitic species, an increase mainly ascribed to the ageing of forests. Among the ectomycorrhizal macromycetes not a single species showed a significant increase, but at least 55 out of 126 species showed a significant decrease. This decline is strongest among species exclusively, or mainly, associated with coniferous trees. At least 15 ectomycorrhizal species seem to have disappeared completely from the Netherlands. Natural forest development, changes in forestry and agriculture and collecting of carpophores are excluded as important factors effecting these changes. The decrease of ectomycorrhizal fungi is mainly attributed to acid precipitation and its effects on soil chemistry and the vitality of trees. However, the exact process is still unknown. Two hypotheses that may explain this phenomenon are discussed.
124 citations
TL;DR: The ability of three ecologically important ectomycorrhizal fungi to utilize each of the biologically active amino acids as sole nitrogen source was assessed, and their growth was compared with that obtained on the two mineral N sources, ammonium and nitrate.
Abstract: The ability of three ecologically important ectomycorrhizal fungi, Suillus bovinus, Amanita muscaria and Hebeloma crustuliniforme to utilize each of the biologically active amino acids as sole nitrogen source was assessed, and their growth was compared with that obtained on the two mineral N sources, ammonium and nitrate. Aspartic and glutamic acids, and amides, together with arginine, alanine and serine all supported growth comparable with that on ammonium in each of the fungi, whereas cysteine, methionine, proline, threonine, tryptophane and tyrosine were not utilized. Interspecific differences were observed in the abilities to utilize the remaining amino compounds. The results are discussed in relation to availability of amino acids in soils and the nitrogen nutrition of the fungi and of their host plants.
120 citations
TL;DR: Mean 137 Cs content of basidiocarps is 3·0–4·8 × higher than before the accident at Chernobyl, and patterns of accumulation are species specific with the pileus more radioactive than the stipe.
Abstract: Mean 137 Cs content of basidiocarps is 3·0–4·8 × higher than before the accident at Chernobyl. Patterns of accumulation of 137 Cs are species specific with the pileus more radioactive than the stipe.
100 citations
TL;DR: Infection experiments with Heterobasidion annosum isolates from S and P intersterility groups were conducted on 4-y-old trees of Picea abies and Pinus sylvestris under greenhouse conditions, and spruce was more susceptible to H.annosum than pine.
Abstract: Infection experiments with Heterobasidion annosum isolates from S and P intersterility groups were conducted on 4-y-old trees of Picea abies and Pinus sylvestris under greenhouse conditions. S-isolates successfully infected spruce, but showed limited growth on pine. P-isolates aggressively attacked pine and also successfully infected spruce. In general, spruce was more susceptible to H. annosum than pine. There was no difference in H. annosum growth upwards or downwards from the inoculation point on the stem. The length of the dry zone formed in the sapwood in advance of H. annosum was independent of the distance that the mycelia had grown.
78 citations
TL;DR: Information is presented on possible origins, and on the distribution of four species of Phytophthora: P. infestons, C. cinnamomi, P. palmivora and P. colocasiae, with indications of an Asiatic origin.
Abstract: Information is presented on possible origins, and on the distribution of four species of Phytophthora: P. infestons, P. cinnamomi, P. palmivora and P. colocasiae . The origin of P. infestons appears to be Mexico where both mating types appear on native species of Solanum , where resistance to the pathogen occurs, and where high variability is found in the population of the fungus. The A1 mating type of this pathogen is the form that has been distributed widely around the world. Recent discovery of the A2 type (previously believed confined to Mexico), in the British Isles, Egypt, and Switzerland, raises some interesting questions and the situation needs further elaboration. P. infestans has undoubtedly been spread around the world by man, probably largely in the potato tuber, shipped to various countries as food or new sources of seed. Data on the centre of origin of P. cinnamomi are more confusing, but there are indications of an Asian origin ranging from New Guinea possibly through Indonesia, Sumatra and Malaysia and including Taiwan, and also another centre in the southern Cape Province of South Africa. The A2 mating type of P. cinnamomi is very widely distributed, with the A1 much less common but predominant in New Guinea and southern South Africa. It could have been carried from an Asian area of origin into Latin America or other areas on soil and plant material transported in voyages by Spanish and other explorers, possibly beginning in the seventeenth century and continuing with increased commerce across the Pacific Ocean. Undoubtedly P. palmivora has been distributed around the world primarily by man, from a possible origin in Central or South America. There are several native hosts in that area, including cacao, rubber, avocado, pineapple, papaya and cotton. Several resistant species are known on which the fungus may have had its origin. Both mating types of P. palmivora are found in many areas around the world, although the A2 is somewhat more commonly isolated. Little information is available on the origin of P. colocasiae , but there are indications of an Asiatic origin. The fungus has undoubtedly been distributed by means of vegetatively propagated material, and probably by soil.
77 citations
TL;DR: Osmotic and matric potential range for germination and germ-tube growth was much wider at 20° than 12° even when the incubation time was doubled to 48 h and F. culmorum was the only species where germination reached 50% or more on leaf sheaths.
Abstract: Effect of osmotic and matric potential on germination and germ tube extension of eight soil fungi was determined on a straw extract agar at 12 and 20 °C and compared with that on sterile or unsterile wheat straw leaf sheaths of different water potentials. Osmotic and matric potential range for germination and germ-tube growth was much wider at 20° than 12° even when the incubation time was doubled to 48 h. In general, germination and germ tube extension of F. culmorum, Trichoderma and Penicillium spp. occurred over a wider osmotic than matric potential range. However, temperature influenced this effect. Gliocladium roseum and G. virens were exceptions having similar osmotic and matric potential ranges for germination and germ-tube extension. On osmotically and matrically modified media, F. culmorum produced significantly longer germ-tubes than Gliocladium, Penicillium and Trichoderma spp. at both 12° and 20°. Germination of all fungi at −0.7 and −2.8 MPa water potential on sterile or unsterile leaf sheaths was significantly less than that obtained at corresponding water potentials on the agar. F. culmorum was the only species where germination reached 50% or more on leaf sheaths.
75 citations
TL;DR: Investigation of the chemotropic response of germinating spores of Gigaspora gigantea to plant roots showed that aerial germ-tubes contacted host roots in 87 % of tomato cultures and in 56 % of corn cultures, and this response was essentially eliminated in the presence of KMnO4 or KOH.
Abstract: Investigation of the chemotropic response of germinating spores of Gigaspora gigantea to plant roots, using a root organ culture assay, showed that aerial germ-tubes contacted host roots in 87 % of tomato cultures and in 56 % of corn cultures. In the presence of KMnO4 or KOH this response was essentially eliminated. With non-hosts, germ-tubes were attracted to beet but not to kohlrabi roots. Contact between germ-tubes and roots of host plants led to a significant stimulation of root growth prior to the formation of any infection structures. In tomato root cultures, both root length and number of laterals increased significantly in response to germ-tube contact. Single fibres of glass wool placed on tomato roots failed to elicit a growth response. In corn root cultures, the number of laterals increased but total root length was unaffected. Roots of beet did not respond to germ-tube contact. Emerging lateral roots frequently grew toward germinating spores of G. gigantea, and this response was reduced in the presence of KMnO4 but not in the presence of KOH. Stimulation of root growth in the pre-infection phase may be a previously unrecognized, non-nutritional benefit of the VAM symbiosis.
68 citations
TL;DR: The view that soil fungi are exclusively aerobic heterotrophs is challenged and evidence is reviewed which shows that fungi participate widely in mineral cycling in soils and are not merely restricted to the role of decomposer organisms.
Abstract: Soils away from the rhizosophere and decomposing wood or other plant residues are generally considered to contain insufficient carbon to allow for the continuous growth of soil fungi. Fungi are thought to subsist on endogenous metabolism or to lie dormant in these soils as spores. In this review the ability of fungi to use diverse metabolic strategies is discussed in relation to growth in these carbon-deficient soils. Fungi may, for example, be capable of growing as oligotrophs, chemolithoheterotrophs or even as chemolithoautotrophs. Some species are also able to grow microaerophilically, or as anaerobes. The view that soil fungi are exclusively aerobic heterotrophs is challenged. The role of fungi in mineral cycling in soils is also discussed. For example, fungi can oxidize reduced forms of N and S, reduce sulphate and nitrate, as well as being able to participate in various mineralization and immobilization reactions. This review aims to reappraise our understanding of how fungi gain energy and biosynthetic carbon in soils, particularly where carbon substrates are in limited supply. Evidence is then reviewed which shows that fungi participate widely in mineral cycling in soils and are not merely restricted to the role of decomposer organisms.
64 citations
TL;DR: Purified sclerotial metabolites from a non-aflatoxigenic strain of A. flavus (NRRL 6541) showed substantial antifeedant activity against Carpophilus hemipterus (Nitidulidae) and one novel analogue of dihydroxyaflavinine and a third unrelated metabolite, compound ‘1’ were also found to deter Carpophile feeding when incorporated into a pinto bean diet.
Abstract: The fungal sclerotium represents an important survival structure in the life cycle of many fungi, including Aspergillus flavus . Purified sclerotial metabolites from a non-aflatoxigenic strain of A. flavus (NRRL 6541) showed substantial antifeedant activity against Carpophilus hemipterus (Nitidulidae). This insect is known to encounter A. flavus sclerotia that form naturally in both standing and downed maize ears. The most abundant active component was dihydroxyaflavinine, but one novel analogue of dihydroxyaflavinine and a third unrelated metabolite, compound ‘1’ were also found to deter Carpophilus feeding when incorporated into a pinto bean diet at 100 p.p.m. d.w. Naturally occurring levels of each of these metabolites were found to be higher than 100 p.p.m. in A. flavus sclerotia. Arthropod predation is recognized as a selective force that has shaped the chemical defence systems of A. flavus and other sclerotium-producing fungi.
TL;DR: Interfertility studies with single-basidiospore isolates showed that the Australian species Armillaria luteobubalina, A. novae-zelandiae, A., fumosa, hinnulea and A. pallidula sp.nov.
Abstract: Interfertility studies with single-basidiospore isolates showed that the Australian species Armillaria luteobubalina, A. novae-zelandiae, A. fumosa, A. hinnulea and A. pallidula sp.nov. are biological species. Single-basidiospore isolates of A. novae-zelandiae from Australia and New Zealand were interfertile, confirming the occurrence of this species in both countries. The occurrence of A. novae-zelandiae, A. futnosa and A. hinnulea in New South Wales and Queensland and A. luteobubalina in South Australia, New South Wales and Queensland is documented. The host range of the latter species has been extended. A. pallidula is described from a plantation of Pinus caribaea on a former subtropical eucalypt forest site in Queensland. The affinities between it, other Australian species, the tropical species A. fuscipes, A. fellea, A. mellea var. camerunensis and a number of Indian species of Armillaria are considered. Detailed descriptions of the micromorphological features of A. fuscipes and A. fellea are given.
TL;DR: The results confirm previously reported developmental sequences of mycorrhizas, and suggest that myCorrhizal fungi differ in ability to infect root tips from inoculum in soil, depending on the age of the subtending root region.
Abstract: Mycelial inocula of ectomycorrhizal fungi were added to 2-yr old saplings of birch ( Betula pendula ) transplanted, with washed roots, from colliery spoil to brown earth soil in troughs in a glasshouse. Lactarius pubescens infected only in older regions of the root systems whereas Hebeloma crustuliniforme (and some Hebeloma spp., from air-borne spores) developed mycorrhizas in all root regions. Mycorrhizas of Thelephora terrestris, Inocybe sp., Paxillus involutus, Laccaria sp., Cenococcum sp. and Leccinum sp. developed from air-borne spores or ( P. involutus ) from inoculum originally on the sapling roots. Their distributions differed along the root systems. Fruit bodies of T. terrestris, Inocybe lacera and H. crustuliniforme showed different distributions within and between years, indicative of a fruit body succession. Periodic inspection of the lower soil surface revealed an increase in occurrence of Hebeloma mycorrhizas with time, but root regions heavily infected by Hebeloma spp. at the end of the second season were also heavily infected after the third season. The results confirm previously reported developmental sequences of mycorrhizas, and suggest that mycorrhizal fungi differ in ability to infect root tips from inoculum in soil, depending on the age of the subtending root region.
TL;DR: Ratios of the radionuclides 137Cs to 134Cs show that a large proportion of the 137Cs present in the fruit bodies is derived from pre-Chernobyl fallout from atomic weapons testing, which suggests accumulation of theRadionuclide by fungal mycelia.
Abstract: Ratios of the radionuclides 137Cs to 134Cs show that a large proportion of the 137Cs present in the fruit bodies is derived from pre-Chernobyl fallout from atomic weapons testing. This suggests accumulation of the radionuclide by fungal mycelia.
TL;DR: Pectic zymogram patterns are proposed as a fast and reliable method of determining anastomosis group in Rhizoctonia solani isolates subjected to electrophoresis in pectin acrylamide gels.
Abstract: Pectic enzymes produced by isolates of Rhizoctonia solani from many hosts and localities within South Australia were subjected to electrophoresis in pectin acrylamide gels. Seven different zymogram groups (ZG) were detected with the majority of isolates being ZG1-1, ZG1–2, ZG1–3 or ZG2. Representatives of these zymogram groups were found in all localities sampled. Of isolates from cereals and legumes, 92% were ZG1-1, ZG1–2, ZG1–3 or ZG2; in contrast, only 23% of isolates from soil were from these zymogram groups. Isolates in ZG1-1, ZG1–2, ZG1–3 and ZG2 were all anastomosis group AG-8, ZG5 were AG-2-1, ZG7 were AG-3 and ZG8 were AG-4. Pectic zymogram patterns are proposed as a fast and reliable method of determining anastomosis group.
TL;DR: A new species, Tapesia yallundae, is described and the anamorph, Pseudocercosporella herpotrichoides, is the cause of eyespot lodging in cereals.
Abstract: A new species, Tapesia yallundae , is described. The anamorph, Pseudocercosporella herpotrichoides , is the cause of eyespot lodging in cereals.
TL;DR: Several examples from both field and laboratory conditions are presented that illustrate non-normal frequency distributions, with the negative binomial distribution often applicable.
Abstract: Spores of Endogonaceous fungi are spatially aggregated in soil, a fact only rarely recognized by researchers. Several examples from both field and laboratory conditions are presented that illustrate non-normal frequency distributions, with the negative binomial distribution often applicable. In experimental work, appropriate analysis of VAMF spore counts allows more sensitive detection of statistical differences than is possible with methods intended for normal distributions.
TL;DR: In sea water/pine pollen cultures, the encysted zoospore divides by repeated binary divisions to form 4, 6, 8 or 12 cells that directly become zoospores in nutrient liquid media.
Abstract: Schizochytrium mangrovei sp. nov. on decaying mangrove leaves is described from Goa, India. In sea water/pine pollen cultures, the encysted zoospore divides by repeated binary divisions to form 4, 6, 8 or 12 cells. Instead of forming sporangia as in the other species of Schizochytrium , these cells directly become zoospores. In nutrient liquid media, the developmental stages resemble those of Ulkenia . A key to the species of Schizochytrium is given.
TL;DR: The phenotypes and genetic basis of these chlorate-resistant mutants resemble those in Aspergillus nidulans and Neurospora crassa, suggesting that nitrate assimilation in S. nodorum is similar to the well-characterized process in these other fungi.
Abstract: Methods were established for growth, sporulation and storage of Septoria nodorum . Following mutagenesis with ultraviolet light or nitrosoguanidine, auxotrophic mutants were isolated in two parent strains by screening survivors on minimal and supplemented media. Pairs of phenotypically-different mutants of the same parent strain complemented each other to produce prototrophic mycelia when co-inoculated onto minimal medium. This procedure was used to assign phenotypically-identical mutations to genes. The most extensive of such complementation analyses involved six arginine-requiring mutants which were assigned to five genes. Growth tests on intermediates of arginine biosynthesis with the same mutants gave results consistent with the complementation analysis and revealed three different points of blockage in the arginine biosynthetic pathway. Spontaneous mutants resistant to potassium chlorate were isolated in five strains by plating pycnidiospores onto chlorate-containing medium. Five phenotypes were distinguished amongst these mutants by growth tests on various nitrogen sources; four of these phenotypes were unable to utilize nitrate. Complementation analysis of these nitrate non-utilizing mutants revealed that at least six different genes were involved. The phenotypes and genetic basis of these chlorate-resistant mutants resemble those in Aspergillus nidulans and Neurospora crassa , suggesting that nitrate assimilation in S. nodorum is similar to the well-characterized process in these other fungi. The mutants isolated are being used in investigations of the pathogenicity and genetics of S. nodorum at the molecular, cellular and population levels.
TL;DR: Two peaks in lesion appearance were observed in each epidemic cycle of M. nubilosa and M. cryptica, and this was attributed to changes in leaf susceptibility with age, inoculum availability, and temperature during the cycle.
Abstract: An epidemiological study of Mycosphaerella nubilosa and M. cryptica was conducted over a three year period. Infection by both fungi occurred during or soon after the vegetation period of the hosts, in periods of high rainfall. The epidemic cycle of M. nubilosa was either monoor bicyclic; that of M. cryptica was typically polycyclic. Two peaks in lesion appearance were observed in each epidemic cycle of M. nubilosa , and this was attributed to changes in leaf susceptibility with age, inoculum availability, and temperature during the cycle. Lesions caused by M. cryptica generally appeared during or soon after the vegetation period of the host, 1–2 months after infection.
TL;DR: It was concluded that in contrast to this phenomenon by conidia of other fungi, iterative germination to form conidia by ascospores of E. typhina is obligatory.
Abstract: Ascospores of Epichloe typhina germinated and produced phialides and conidia within a 24 h period, but produced no mycelium. This type of microcycle conidiation was referred to as iterative germination. All attempts at producing mycelium from ascospores failed; ascospores developed conidia under all cultural conditions tried in the study. Conidia produced during the process were viable, and morphologically similar to those produced in culture by mycelium, and to those produced by the fungus on its host meadow grass, Sphenopholis obtusata. This is the first report of microcycle conidiation by ascospores. Since the ascospores required no thermal or precultural induction period, it was concluded that in contrast to this phenomenon by conidia of other fungi, iterative germination to form conidia by ascospores of E. typhina is obligatory.
TL;DR: Eucalypt seedlings with Mycosphaerella nubilosa and M. cryptica were carried out to determine infection requirements, and young expanding leaves were most readily infected, and leaves became more resistant with age.
Abstract: Inoculations of eucalypt seedlings with Mycosphaerella nubilosa and M. cryptica were carried out to determine infection requirements. M. nubilosa could only infect susceptible leaves when spores were applied to the abaxial surface. M. cryptica was able to infect leaves from either surface. Young expanding leaves were most readily infected, and leaves became more resistant with age. M. nubilosa was able to infect slightly older expanded leaves, but the incubation period was much longer. Optimal infection by both fungi occurred with 5–7 d leaf wetness at 15–20 °C. Spores of M. nubilosa and M. cryptica survived with little loss in infectivity for up to 7 and 4 d respectively following deposition on the leaf surface.
CABI1
TL;DR: The history of the species and its relationships with species of Ramularia, Ophiocladium and Ovularia are discussed.
Abstract: Ramularia collo-cygni nom.nov. is introduced for Ophiocladium hordei , non Ramularia hordei , and described from Hordeum, Phalaris, Glyceria and Triticale. The history of the species and its relationships with species of Ramularia, Ophiocladium and Ovularia are discussed.
TL;DR: Field and growth chamber studies indicated that treatment did not significantly affect the leaves as a habitat for microbes and Variability among treated leaves in numbers of species, numbers of individuals, and species composition was less than among control leaves following recolonization in the field.
Abstract: In vivo immersion of apple leaves in 15% hydrogen peroxide solution for 75–90 s resulted in about 99% reduction of phylloplane bacteria and fungi without appreciable phytotoxicity. Field and growth chamber studies indicated that treatment did not significantly affect the leaves as a habitat for microbes. Variability among treated leaves in numbers of species, numbers of individuals, and species composition was less than among control leaves following recolonization in the field.
TL;DR: Genetically discrete dikaryotic individuals can be defined for C. cinereus on the basis of self/non-self interactions and provide the basis for further population and evolutionary studies with this genetically well-characterized species.
Abstract: This study addresses the question of whether or not genetically different dikaryons constitute discrete individuals in the coprophilous Basidiomycete, Coprinus cinereus. The effects of both nuclear and mitochondrial genomic differences were investigated. Dikaryons that differed in nuclear genomes exhibited varying degrees of antagonism (somatic incompatibility) when paired in culture. Sources of variation in the antagonistic response were genetic relatedness, geographical separation and the degree to which strains were subcultured. Paired dikaryons with different mitochondrial genomes but with common nuclear genomes gave rise to antagonism in one case but most often appeared to tolerate these differences and to intermingle. Dikaryon x monokaryon crosses resulting in dikaryons differing by one nucleus produced similar somatic incompatibility reactions as in dikaryon/dikaryon interactions. Di-mon crosses resulting in dikaryons with the same nuclear genomes did not, for the most part, exhibit antagonism. Genetically discrete dikaryotic individuals can be defined for C. cinereus on the basis of self/non-self interactions. These findings provide the basis for further population and evolutionary studies with this genetically well-characterized species.
CABI1
TL;DR: The genus Polycoccum (Dothideales) is referred to an extended concept of the Dacampiaceae rather than to the Pleosporaceae, and attention is drawn to problems in the lectotypification of the generic name Didymosphaeria.
Abstract: The genus Polycoccum (Dothideales) is referred to an extended concept of the Dacampiaceae rather than to the Pleosporaceae. It is distinguished from Didymosphaeria by the structure of the ascomata. A key to, spore outlines of, and notes on the 23 accepted species are provided, including P. cladoniae sp.nov. ; they are primarily lichenicolous and often gall-forming. Notes on 29 epithets excluded from the genus, including all lichenicolous taxa referred to Didymosphaeria, are provided, and the following combination made : Endococcus gyrophorarum (Arnold) comb.nov. Attention is also drawn to problems in the lectotypification of the generic name Didymosphaeria.
TL;DR: A specific role for micro-organisms associated with root surfaces in antagonizing and limiting infection of roots by P. cinnamomi zoospores is indicated.
Abstract: Investigation of the behaviour of Phytophthora cinnamomi zoospores on non-mycorrhizal and ectomycorrhizal roots of Eucalyptus marginata seedlings showed that zoospores encysted and germinated on both root types, but subsequent infection of root tissues was influenced by the type of ectomycorrhizal symbiont and the mycorrhizosphere population associated with the roots. In general, there was little evidence of colonization of P. cinnamomi zoospore cysts or germ tubes by the bacterial and/or actinomycete flora in the rhizoplane of non-mycorrhizal roots of seedlings growing in podsolic soil. On the other hand, there was extensive colonization of the fungus propagules on non-mycorrhizal roots in litter by bacteria and/or actinomycetes. Recovery of the pathogen was also markedly less from these roots than from similar root types growing in soil. Ectomycorrhizas formed by the ascomycete Cenococcum geophilum and the basidiomycete Hysterangium inflation failed to limit root infection in soil and the pathogen was recovered from both root types after 55 d incubation. There was no recovery of the pathogen from ‘white type’ basidiomycete ectomycorrhizas even after 24 h incubation. Micrographs showed zoospores either germinating but failing to penetrate the mantle or being enveloped and parasitized by a range of morphologically distinctive bacteria and a fungus within hours of inoculation of roots with zoospores. The data indicate a specific role for micro-organisms associated with root surfaces in antagonizing and limiting infection of roots by P. cinnamomi zoospores.
TL;DR: Protection against thermal inactivation was increased when ascospores were heated in apple juice supplemented with sugars at concentrations sufficient to reduce the aw to 0.96 (60% sucrose, 34.5 % glucose and fructose).
Abstract: Investigations were conducted to determine the influence of growth media, temperature of incubation, age of culture and sugars (sucrose, glucose and fructose) in an apple juice heating medium on thermal tolerance characteristics of Talaromyces flavus ascospores. Of eight culture media tested, carbohydrate-rich formulae supported highest levels of ascospore production. Heat-resistant ascospores developed most rapidly on oatmeal agar, and in all instances increased tolerance to heat was correlated with age of cultures up to 30 d of incubation; little change in heat tolerance was noted as cultures aged from 30 to 58 d. Heat resistance was less when T. flavus was grown at 21 °C compared to 25 and 30°. Protection against thermal inactivation was increased when ascospores were heated in apple juice supplemented with sugars at concentrations sufficient to reduce the aw to 0.96 (60% sucrose, 34.5 % glucose and fructose). This protective effect was not influenced by the type of sugar.
TL;DR: Twelve new species are described: Conocybe sordescens, Coprinus cinnamomeotinctus, C. griseofoetidus, Pholiota ceriferoides, P. xanthophaea, and Tephrocybe ellisii.
Abstract: Twelve new species are described: Conocybe sordescens, Coprinus cinnamomeotinctus, C. griseofoetidus (a renaming of C. narcoticus (Batsch: Fr.) Fr. sensu J. Lange), Galerina paludinella, G. viscidula, Leccinum rigidipes, Lepiota olivaceobrunnea, Mycena fusconigra (a renaming of M. atrocyanea (Batsch: Fr.) Gillet), Pholiota ceriferoides, P. persicina, P. xanthophaea, and Tephrocybe ellisii. Hygrophorus micaceus is transferred to Hygrocybe and the necessary new combination is proposed and a recent collection is described. Descriptions are given of recent British material of Clitocybe ornamentalis, C. truncicola, Cortinarius (Phlegmaciurn) gracilior, C. (P.) magicus, C. (P.) varius, C. (P.) xanthophyllus, Entoloma myrmecophilum, E. sphagneti, Gymnopilus bellulus, Hebeloma funariophyllum, Lepiota tomentella, Mycena leucogala, M. trichoderma, Stropharia albonitens and Tephrocybe platypus. The following taxa are discussed but not described: Cortinarius (Telamonia) pseudocolus, C. (T.) haematochelis (both of which are newly recorded for Britain), Leccinum quercinum (occurring under aspen in Scotland) and Pluteus villosus (amended dimensions of cap and stem).
TL;DR: Maximal activity was positively correlated to maximum fruit body production and manipulation of individual flush patterns, by altered harvesting strategies, also positively regulated endocellulase activity.
Abstract: Extracellular endocellulase activity was assayed in extracts from mycelium-colonized compost during growth and fruiting of Agaricus bisporus . Fluctuations in extracted enzyme activity were observed which were related to the cycles of fruit body biomass production. Maximal activity was positively correlated to maximum fruit body production and manipulation of individual flush patterns, by altered harvesting strategies, also positively regulated endocellulase activity.