Showing papers in "Mycologia in 2004"
TL;DR: The zoospore activity, physiology and protease production of B. dendrobatidis is investigated to help understand the epidemiology of this pathogen, which is implicated in severe population declines on several continents.
Abstract: Batrachochytrium dendrobatidis is a patho- gen of amphibians that has been implicated in severe population declines on several continents. We inves- tigated the zoospore activity, physiology and protease production of B. dendrobatidis to help understand the epidemiology of this pathogen. More than 95% of zoospores stopped moving within 24 h and swam less than 2 cm before encysting. Isolates of B. den- drobatidis grew and reproduced at temperatures of 4- 25 C and at pH 4-8. Growth was maximal at 17-25 C and at pH 6-7. Exposure of cultures to 30 C for 8 d killed 50% of the replicates. B. dendrobatidis cul- tures grew on autoclaved snakeskin and 1% keratin agar, but they grew best in tryptone or peptonized milk and did not require additional sugars when grown in tryptone. B. dendrobatidis produced extra- cellular proteases that degraded casein and gelatin but had no measurable activity against keratin azure. The proteases were active against azocasein at tem- peratures of 6-37 C and in a pH range of 6-8, with the highest activity at temperatures of 23-30 C and at pH 8. The implications of these observations on disease transmission and development are discussed.
679 citations
TL;DR: A combined phylogeny of the three gene regions used in this study showed that the genus Botryosphaeria represents two distinct phylogenetic assemblages that correspond to species with Diplodia and Fusicoccum anamorphs.
Abstract: Botryosphaeria dothidea is one of the most commonly reported species in a genus of important pathogens of woody plants. This taxon generally is accepted to represent a species complex, and hence its identity remains unclear. Previous studies either have treated B. dothidea as the valid name for B. ribis and B. berengeriana or argued for them to be separate entities. To add to the confusion, no ex-type cultures are available for either B. dothidea or B. ribis. The aim of the present study, therefore, was to recollect and characterize these fungi and designate a set of reference cultures that can be used in future studies. To this end, morphological, cultural and multi-allelic DNA sequence datasets from the rDNA (ITS 1, 5.8S, and ITS 2), β-tubulin and EF1-α genes were used to fully characterize these species. Botryosphaeria dothidea was found to be distinct from B. ribis, while B. berengeriana was retained as synonym of the former name. Furthermore, Fusicoccum aesculi is accepted as anamorph of B. dothidea, while the anamorph of B. ribis is newly described as F. ribis sp. nov. Botryosphaeria ribis could be distinguished from B. parva based on β-tubulin and EF1-α sequence data. A combined phylogeny of the three gene regions used in this study also showed that the genus Botryosphaeria represents two distinct phylogenetic assemblages that correspond to species with Diplodia and Fusicoccum anamorphs.
308 citations
TL;DR: It is concluded that B. australis, B. ribis and B. stevensii are more virulent than the other species studied, confirming earlier suggestions that the generic concept of Botryosphaeria should be expanded to include genera with septate ascospores and Diplodia anamorphs.
Abstract: Several species of Botr yosphaeria are known to occur on grapevines, causing a wide range of disorders including bud mortality, dieback, brown wood streaking and bunch rot. In this study the 11 Botryosphaeria spp. associated with grapevines growing in various parts of the world, but primarily in South Africa, are distinguished based on morphology, DNA sequences (ITS-1, 5.8S, ITS-2 and EF1-α) and pathological data. Botryosphaeria australis, B. lutea, B. obtusa, B. parva, B. rhodina and a Diplodia sp. are confirmed from grapevines in South Africa, while Diplodia porosum, Fusicoccum viticlavatum and F. vitifusiforme are described as new. Although isolates of B. dothidea and B. stevensii are confirmed from grapevines in Portugal, neither of these species occurred in South Africa, nor were any isolates of B. ribis confirmed from grapevines. All grapevine isolates from Portugal, formerly presumed to be B. ribis, are identified as B. parva based on their EF1-α equence data. From artificial inoculations on grapevine shoots, we conclude that B. australis, B. parva, B. ribis and B. stevensii are more virulent than the other species studied. The Diplodia sp. collected from grapevine canes is morphologically similar but phylogenetically distinct from D. sarmentorum. Diplodia sarmentorum is confirmed as anamorph of Otthia spiraeae, the type species of the genus Otthia (Botryosphaeriaceae). A culture identified as O. spiraeae clustered within Botryosphaeria and thus is regarded as probable synonym. These findings confirm earlier suggestions that the generic concept of Botryosphaeria should be expanded to include genera with septate ascospores and Diplodia anamorphs.
265 citations
TL;DR: It was concluded that the isolates from oak differed from B. stevensii in having larger ascospores and conidia as well as different spore shapes and represented an as yet undescribed species, which is described here as B. corticola.
Abstract: Botr yosphaeria stevensii frequently has been associated with dieback and canker diseases of oak, mainly in the western Mediterranean area but more rarely in other regions. The species concept of B. stevensii has been unclear, and it is possible that some collections were identified incorrectly. A collection of fungal strains isolated from diseased oak trees and initially identified as B. stevensii was characterized on the basis of morphology and ITS nucleotide sequences. Morphology was compared with the type specimens of Physalospora mutila (= B. stevensii) and its anamorph, Diplodia mutila. It was concluded that the isolates from oak differed from B. stevensii in having larger ascospores and conidia as well as different spore shapes and represented an as yet undescribed species, which is described here as B. corticola. Moreover, ITS sequence data separated B. corticola from all other known species of Botryosphaeria. Amended descriptions of B. stevensii and its anamorph are provided to differentiate B. stevensii from B. corticola and to clarify some of the earlier taxonomic uncertainties.
194 citations
TL;DR: The causal agents of Alternaria brown spot of tangerines and tangerine hybrids, Alternaria leaf spot of rough lemon and Alternaria black rot of citrus historically have been referred to as Alternaria citri or A. alternata, and the number of morphospecies associated with citrus exceeded that which could be supported under a phylogenetic species concept, and isolates in five of nine phylogenetic lineages consistently were correlated with a specific host, disease or ecological niche on citrus.
Abstract: The causal agents of Alternaria brown spot of tangerines and tangerine hybrids, Alternaria leaf spot of rough lemon and Alternaria black rot of citrus historically have been referred to as Alternaria citri or A. alternata. Ten species of Alternaria recently were described among a set of isolates from leaf lesions on rough lemon (Citrus jambhiri) and tangelo (C. paradisi × C. reticulata), and none of these isolates was considered representative of A. alternata or A. citri. To test the hypothesis that these newly described morphological species are congruent with phylogenetic species, selected Alternaria brown spot and leaf spot isolates, citrus black rot isolates (post-harvest pathogens), isolates associated with healthy citrus tissue and reference species of Alternaria from noncitrus hosts were scored for sequence variation at five genomic regions and used to estimate phylogenies. These data included 432 bp from the 5' end of the mitochondrial ribosomal large subunit (mtLSU), 365 bp from the 5' end of the beta-tubulin gene, 464 bp of an endopolygalacturonase gene (endoPG) and 559 and 571 bp, respectively, of two anonymous genomic regions (OPA1-3 and OPA2-1). The mtLSU and beta-tubulin phylogenies clearly differentiated A. limicola, a large-spored species causing leaf spot of Mexican lime, from the small-spored isolates associated with citrus but were insufficiently variable to resolve evolutionary relationships among the small-spored isolates from citrus and other hosts. Sequence analysis of translation elongation factor alpha, calmodulin, actin, chitin synthase and 1, 3, 8-trihydroxynaphthalene reductase genes similarly failed to uncover significant variation among the small-spored isolates. Phylogenies estimated independently from endoPG, OPA1-3 and OPA2-1 data were congruent, and analysis of the combined data from these regions revealed nine clades, eight of which contained small-spored, citrus-associated isolates. Lineages inferred from analysis of the combined dataset were in general agreement with described morphospecies, however, three clades contained more than one morphological species and one morphospecies (A. citrimacularis) was polyphyletic. Citrus black rot isolates also were found to be members of more than a single lineage. The number of morphospecies associated with citrus exceeded that which could be supported under a phylogenetic species concept, and isolates in only five of nine phylogenetic lineages consistently were correlated with a specific host, disease or ecological niche on citrus. We advocate collapsing all small-spored, citrus-associated isolates of Alternaria into a single phylogenetic species, A. alternata.
183 citations
TL;DR: Two new orders, Coniochaetales and Chaetosphaeriales, are recognized and the Boliniaceae is accepted in the Boliniales, and the Nitschkiaceae is acceptance in the Coronophorales.
Abstract: The Sordariales is a taxonomically diverse group that has contained from seven to 14 families in recent years. The largest family is the Lasiosphaer- iaceae, which has contained between 33 and 53 gen- era, depending on the chosen classification. To de- termine the affinities and taxonomic placement of the Lasiosphaeriaceae and other families in the Sor- dariales, taxa representing every family in the Sor- dariales and most of the genera in the Lasiosphaeri- aceae were targeted for phylogenetic analysis using partial sequences of the large-subunit (LSU) nrDNA. Based on molecular data, only genera within the fam- ilies Chaetomiaceae, Lasiosphaeriaceae and Sordari- aceae are retained within the redefined Sordariales. The order is a coherent group with morphologies that vary along well-defined lines, including large as- comata with large-celled membraneous or coriaceous walls and ascospores that show variation on a distinc- tive developmental theme, often with appendages or sheaths. The paraphyletic chaetomiaceous complex and the strongly supported Sordariaceae are nested among taxa traditionally placed in the Lasiosphaeri- aceae. Analyses also indicate that 11 genera belong in the paraphyletic lasiosphaeriaceous complex. These taxa share a similar developmental pattern in their ascospore morphology that extends to the Sor- dariales as a whole. Based on these similarities in morphology, 13 additional genera are retained within the lasiosphaeriaceous complex and more than 35 genera have relationships in the order overall. Based on LSU data, 17 genera that have been assigned to the Lasiosphaeriaceae sensu lato are transferred to
156 citations
TL;DR: E. weberi is a necrotrophic parasite of the fungal cultivar of attine ants and can secrete compounds that break down host mycelium before contact occurs, unlike invasive necrotrophs that always penetrate host hyphae.
Abstract: Fungi in the genus Escovopsis are known only from the fungus gardens of attine ants. Previous work has established that these anamorphic fungi, allied with the Hypocreales, are specialized and potentially virulent parasites of the ancient mutualism between attine ants and their fungal cultivars. It is unclear whether the primary nutrient source for the pathogen is the mutualist fungal cultivar or the vegetative substrate placed on the gardens by the ants. Here, we determine whether Escovopsis weberi is a parasite of the fungal cultivar, a competitor for the leaf substrate, or both. Bioassays reveal that E. weberi exhibits rapid growth on pure cultivar and negligible growth on sterilized leaf fragments. Light microscopy examination of hyphalhyphal interactions between E. weberi and the ant fungal cultivar indicate that E. weberi, unlike invasive necrotrophs that always penetrate host hyphae, can secrete compounds that break down host mycelium before contact occurs. Thus, E. weberi is a necrotrophic parasite of the fungal cultivar of attine ants.
122 citations
TL;DR: Host relationships and the presence of chlamydospores in culture proved to be important characteristics in the systematics as well as the phylogenetic relationships of Ganoderma.
Abstract: Characteristics and structures of mt SSU rDNA were investigated for the phylogenetic study of Ganoderma. Phylogenetic information was concentrated mostly in the V1, V4, V5, V6 and V9 variable domains, but informative sites in conserved domains also significantly contributed in resolving phylogenetic relationships between Ganoderma groups. Secondary structure information of variable domains was found to be a useful marker in delineation of phylogenetic groups. Strains of Ganoderma species used in this study were divided into six monophyletic groups. Ganoderma colossus made a distinct basal lineage from other Ganoderma species and Tomophagus, created for G. colosuss, appeared to be a valid genus. Ganoderma applanatum and G. lobatum classified in subgenus Elfvingia made a monophyletic group. Ganoderma tsugae from North America and G. valesiacum from Europe, both living on conifers, were closely related. Ganoderma oregonense and strains labeled G. lucidum from Europe and Canada were grouped with G. tsugae and G. valesiacum. Strains labeled G. lucidum living on hardwoods from the United States and Taiwan were grouped with G. resinaceum, G. pfeifferi and G. subamboinense var. laevisporum, and they all produced chlamydospores. Two strains labeled G. lucidum and three strains labeled G. resinaceum from America were concluded to be conspecific. Strains labeled G. lucidum from Korea and Japan were monophyletic and were distinguished from strains labeled G. lucidum from Europe and North America. Host relationships and the presence of chlamydospores in culture proved to be important characteristics in the systematics as well as the phylogenetic relationships of Ganoderma.
115 citations
TL;DR: Phylogenetic analysis of the 18S nr DNA demonstrates that Paecilomyces is polyphyletic across two subclasses, Sordariomycetidae and Eurotiomycetusidae, and within the Eurotiales, species of PaecILomyces are polyphylets, although the data failed to fully resolve these relationships.
Abstract: Nuclear-encoded small-subunit ribosomal DNA was used to examine phylogenetic relationships in Paecilomyces sensu lato. Phylogenetic analysis of the 18S nr DNA demonstrates that Paecilomyces is polyphyletic across two subclasses, Sordariomycetidae and Eurotiomycetidae. The type species, Paecilomyces variotii, and thermophilic relatives belong in the order Eurotiales (Trichocomaceae), while mesophilic species related to Paecilomyces farinosus are in the order Hypocreales (Clavicipitaceae and Hypocreaceae). One species, Paecilomyces inflatus, had affinities for the order Sordariales. Within the Eurotiales, Paecilomyces is monophyletic. Within the Hypocreales, species of Paecilomyces are polyphyletic, although the data failed to fully resolve these relationships.
108 citations
TL;DR: The results show that Cortinarius consists of many lineages, but the relationships among these clades could not be elucidated, and more extensive taxon sampling is essential to resolve the phylogeny of this important genus of ectomycorrhizal fungi.
Abstract: Research on the molecular systematics of Cortinarius, a species-rich mushroom genus with nearly global distribution, is just beginning. The pre- sent study explores infrageneric relationships using rDNA ITS and LSU sequence data. One large dataset of 132 rDNA ITS sequences and one combined da- taset with 54 rDNA ITS and LSU sequences were gen- erated. Hebeloma was used as outgroup. Bayesian analyses and maximum-likelihood (ML) analyses were carried out. Bayesian phylogenetic inference performed equally well or better than ML, especially in large datasets. The phylogenetic analysis of the combined dataset with species representing all cur- rently recognized subgenera recovered seven well- supported clades (Bayesian posterior probabilities BPP . 90%). These major clades are: /Myxacium s.l., /subg. Cortinarius, the /phlegmacioid clade (includ- ing the subclades /Phlegmacium and /Delibuti), the /calochroid clade (/Calochroi, /Ochroleuci and /Allutus), the /telamonioid clade (/Telamonia, /Or- ellani, /Anomali), /Dermocybe s.l. and /Myxotela- monia. Our results show that Cortinarius consists of many lineages, but the relationships among these clades could not be elucidated. On one hand, the low divergence in rDNA sequences can be held re- sponsible for this; on the other hand, taxon sampling is problematic in Cortinarius phylogeny. Because of the incredibly high diversity (;2000 Cortinarius spe- cies), our sampling included ,5% of the known spe- cies. By choosing type species of subgenera and sec- tions, our sampling is strongly biased toward North- ern Hemisphere taxa. More extensive taxon sam- pling, especially of species from the Southern
100 citations
TL;DR: Re-analyses of GenBank data showed that B. australis also occurs on other native Australian hosts, namely a Banksia sp.
Abstract: Botryosphaeria lutea (anamorph Fusicoc- cum luteum) most easily is distinguished from other Botryosphaeria spp. by a yellow pigment that is formed in young cultures. This fungus has been re- ported from a number of cultivated hosts in New Zea- land and Portugal. During a survey of Botryosphaeria fungi that occur on native Acacia species in Australia, a yellow pigment was observed in some cultures. These isolates were morphologically similar to B. lu- tea, but the pigment differed slightly from the one formed by authentic B. lutea isolates. Preliminary data also revealed small differences in ITS rDNA se- quence data. The aim of this study was to determine whether these small differences were indicative of separate species or merely variations within B. lutea. Anamorph, teleomorph and culture morphology were compared between B. lutea and Acacia isolates from Australia. Sequence data of two other genome regions, namely the b-tubulin and EF1-a gene and intron regions, were combined with ITS rDNA se- quence data to determine the phylogenetic relation- ship between these isolates. Isolates of B. lutea and those from Australian Acacia species were not signif- icantly different in spore morphology. The yellow pigment, however, was much more distinct in cul- tures of B. lutea than in cultures from Acacia. There
TL;DR: In this paper, the authors identify Colletotrichum spp. associated with diseases of cultivated Proteaceae based on morphology, sequence data of the internal transcribed spacer region (ITS-1, ITS-2), the 5.8S gene, and partial sequences of the b- tubulin gene.
Abstract: Colletotrichum spp. are known to occur on and cause diseases of Proteaceae, but their identities are confused and poorly understood. The aim of the present study thus was to identify accurately the Col- letotrichum spp. associated with diseases of cultivated Proteaceae. Colletotrichum spp. associated with pro- teaceous hosts growing in various parts of the world were identified based on morphology, sequence data of the internal transcribed spacer region (ITS-1, ITS- 2), the 5.8S gene, and partial sequences of the b- tubulin gene. Four species of Colletotrichum were found to be associated with Proteaceae. Colletotri- chum gloeosporioides, a cosmopolitan species known to occur on numerous hosts, was isolated from Protea cynaroides cultivated in South Africa and Zimbabwe, and from a Leucospermum sp. in Portugal. A recently described species, C. boninense was associated with Zimbabwean and Australian Proteaceae but also oc- curred on a Eucalyptus sp. in South Africa. This rep- resents a major geographical and host extension for the species and a description of the African strains is
TL;DR: Activity of laccase B was inhibited strongly by sodium azide and cyanide, mildly by SDS and trifluoroacetic acid, but only weakly by dimethyl sulfoxide, and the enzyme showed a good stability in a range of pH value of 3.5–7.5.
Abstract: The white-rot fungus Trametes sp. AH28-2 can synthesize extracellular laccase by induction in cellobiose-based liquid culture medium. Both yields and composition of laccase isozymes, produced by Tr...
TL;DR: A new family is proposed, Ajellomycetaceae, based on molecular data and on morphological and physiological similarities among these taxa that are saprobic and pathogenic vertebrate-associated taxa distinguished by their globose ascomata with coiled appendages, muricate globose or oblate ascospores, and lack of keratinolytic activity.
Abstract: Phylogenies inferred from the analysis of DNA sequence data have shown that the Onygenales contains clades that do not correspond with previously described families. One lineage identified in recen...
TL;DR: A neutral serine protease (designated Aoz1) was purified to homogeneity from a strain of Arthrobotrys oligospora, obtained from soil in Yunnan Province, and it is concluded that this gene is likely a PII ortholog.
Abstract: A neutral serine protease (designated Aoz1) was purified to homogeneity from a strain of Arthrobotrys oligospora, obtained from soil in Yunnan Province. The purified protein showed a molecular mass of approximately 38 000 Dalton, pI 4.9 and displayed optimal activity at 45 C and pH 6–8. The protein could hydrolyze gelatin, casein and the chromogenic substrate azocoll, and it could immobilize nematodes in vitro (Panagrellus redivivus L. [Goodey]). The level of activity in culture medium was found to increase with increasing gelatin concentration. Scanning electron micrographs demonstrated dramatic structural changes in nematode cuticle treated with the purified protease. A partial peptide sequence obtained by N-terminal sequence analysis was used to design degenerate primers for the isolation of a cDNA gene encoding the mature protease. Analysis of the cDNA and corresponding genomic sequence revealed 97% identity with PII, a gene previously described from A. oligospora, and we conclude that this gene is li...
TL;DR: It was concluded that the isolates from oak differed from B. stevensii in having larger ascospores and conidia as well as different spore shapes and represented an as yet undescribed species, which is described here as B. corticola.
Abstract: Botr yosphaeria stevensii frequently has been associated with dieback and canker diseases of oak, mainly in the western Mediterranean area but more rarely in other regions. The species concept of B. stevensii has been unclear, and it is possible that some collections were identified incorrectly. A collection of fungal strains isolated from diseased oak trees and initially identified as B. stevensii was characterized on the basis of morphology and ITS nucleotide sequences. Morphology was compared with the type specimens of Physalospora mutila (= B. stevensii) and its anamorph, Diplodia mutila. It was concluded that the isolates from oak differed from B. stevensii in having larger ascospores and conidia as well as different spore shapes and represented an as yet undescribed species, which is described here as B. corticola. Moreover, ITS sequence data separated B. corticola from all other known species of Botryosphaeria. Amended descriptions of B. stevensii and its anamorph are provided to differentiate B. stevensii from B. corticola and to clarify some of the earlier taxonomic uncertainties.
TL;DR: The data suggest that recruitment or loss of these secondary metabolite pathway genes has a selective advantage apart from the physiological activity of the metabolite.
Abstract: The Aspergillus nidulans sterigmatocystin (ST) gene cluster contains both regulatory (aflR) and biosynthetic genes (stc genes) required for ST production. A total of 26 genes are in the cluster, 13 of which have been assigned a known function in the biosynthetic pathway. This complex secondary pathway represents a physiological cost to the fungus. We tested the amount of asexual spore production using a series of isogenic lines of A. nidulans, differing only in a mutation in aflR (resulting in a strain containing no ST intermediates) or a mutation in three stc genes that produced either no ST intermediates (ΔstcJ), an early ST intermediate, norsoloroinic acid (ΔstcE) or a late ST intermediate, versicolorin A (ΔstcU). In two independently replicated experiments we compared the numbers of conidia produced by each of these mutant strains and a wild type ST producer in a neutral (growth media) and a host (corn seed) environment. A stepwise increase in asexual spore production was observed with each progressive step in the ST pathway. Thus, the data suggest that recruitment or loss of these secondary metabolite pathway genes has a selective advantage apart from the physiological activity of the metabolite.
TL;DR: The cumulative genotypic and phenotypic data support a species distinction between these two organisms, P. carinii and P. wakefieldiae, which is described here.
Abstract: Organisms in the genus Pneumocystis are fungi that reside in the lungs of mammals that can cause a lethal pneumonia once the hosts lose immune function. The genus Pneumocystis contains many members, but only two species have been described formally to date, P. carinii, the type species found in rats, and P. jirovecii, resident in human beings. Rats have been shown to harbor another organism in addition to P. carinii, Pneumocystis wakefieldiae sp. nov., formerly known as Pneumocystis carinii f. sp. ratti, which is described here. Although often found together and morphologically similar, P. carinii and P. wakefieldiae are phenotypically and genetically divergent. We used the phylogenetic species recognition approach to distinguish these organisms as two distinct species and estimated the evolutionary time of their separation. Nucleotide sequence comparisons of seven homologous genes showed 4-7% divergence between the P. wakefieldiae and P. carinii sequences, which was in contrast to the 0-0.8% divergence observed within P. carinii species. Even greater divergence (30%) occurred in sequences located between genes. The MSG (major surface glycoprotein) gene families of P. carinii and P. wakefieldiae are 35% divergent from one another and differ with respect to sequence elements associated with regulation of their transcription. Differences in reactivity of monoclonal antibodies and polyclonal antisera reflected these genetically distinct surface antigens. Karyotypic analysis of P. wakefieldiae produced a single profile that was distinct from all 12 profiles known for P. carinii. Eight homologous genes were localized to chromosomes of different sizes in the two species. The cumulative genotypic and phenotypic data support a species distinction between these two organisms.
TL;DR: In general, the concentration of total sugar alcohols in mycelia increased as osmotic and matric potential were reduced to −1.2 MPa, however, this increase was more evident inMycelia from glycerol-amended media.
Abstract: Studies were conducted to determine the effect of osmotic (NaCl, glycerol) and matric (PEG 8000) water stress on temporal germination and growth of two F. graminearum strains over the water potential range of -0.7 to -14.0 MPa at 15 and 25 C. The effect on endogenous water potentials and accumulation of sugars and sugar alcohols also were measured. For both strains, germination occurred rapidly over the same range of osmotic or matric potential of -0.7 to -5.6 MPa after 4-6 h incubation. At lower osmotic and matric potentials (-7.0 to -8.4 MPa), there was a lag of up to 24 h before germination. Optimum germ-tube extension occurred between -0.7 and -1.4 MPa for both strains but varied with the solute used. Growth was optimal at -1.4 MPa and 25 C in response to matric stress, with the minimum being about -8.0 and -11.2 MPa at 15 and 25 C, respectively. In contrast, F. graminearum grew fastest at -0.7 MPa and was more tolerant of solute stress modified with either glycerol or NaCl with a minimum of about -14.0 MPa at 15 and 25 C. A decrease in the osmotic/matric water potential of the media caused a large decrease in the mycelial water potential (Ψ(c)) as measured by thermocouple psychrometry. In general, the concentration of total sugar alcohols in mycelia increased as osmotic and matric potential were reduced to -1.2 MPa. However, this increase was more evident in mycelia from glycerol-amended media. The quality of the major sugar alcohol accumulated depended on the solute used to generate the water stress. The major compounds accumulated were glycerol and arabitol on osmotically modified media and arabitol on matrically modified media. In response to matric stress, the concentration of trehalose in colonies generally was higher in the case of osmotic stress. In each water-stress treatment there was a good correlation between Ψ(c) and total sugar alcohol content.
TL;DR: Species of Neurospora, heretofore thought to occur mainly in moist tropical and subtropical regions, are common primary colonizers of trees and shrubs killed by forest fires in western North America, in regions that are often cold and dry.
Abstract: The fungal genus Neurospora has a distinguished history as a laboratory model in genetics and biochemistry. The most recent milestone in this history has been the sequencing of the genome of the best known species, N. crassa. The hope and promise of a complete genome sequence is a full understanding of the biology of the organism. Full understanding cannot be achieved, however, in the absence of fundamental knowledge of natural history. We report that species of Neurospora, heretofore thought to occur mainly in moist tropical and subtropical regions, are common primary colonizers of trees and shrubs killed by forest fires in western North America, in regions that are often cold and dry. Surveys in 36 forest-fire sites from New Mexico to Alaska yielded more than 500 cultures, 95% of which were the rarely collected N. discreta. Initial characterization of genotypes both within a site and on a single tree showed diversity consistent with sexual reproduction of N. discreta. These discoveries fill important gaps in knowledge of the distribution of members of the genus on both large and small spatial scales and provide the framework for future studies in new regions and microhabitats. The overall result is that population biology and genetics now can be combined, placing the genus Neurospora in a unique position to expand its role in experimental biology as a useful model organism for ecology, population genetics and evolution.
TL;DR: The influence of T. longibrachiatum on the production of lignocellulolytic enzymes by Pleurotus ostreatus during its vegetative growth on a straw-based cultivation substrate that either had been sterilized, pasteurized or not heat treated was investigated.
Abstract: Trichoderma spp., soil filamentous fungi, are antagonists that can cause great losses in mushroom production. We have investigated the influence of T. longibrachiatum on the production of lignocell...
TL;DR: Two fossil poroid hymenophore fragments, one from the Cretaceous Period and the Eocene Epoch, are described and interpreted as belonging to basidiomycete lineages, with persistent, leathery or corky basidiomata.
Abstract: Two fossil poroid hymenophore fragments, one from the Cretaceous Period and the other from the Eocene Epoch, are described. The permineralized specimens were obtained from marine calcareous concretions on Vancouver Island, British Columbia, Canada, and were studied using the cellulose acetate peel technique. Size and distribution of pores in the hymenophores, as well as the hyphal anatomy of the dissepiments and some hymenial elements, were examined. In the Cretaceous specimen, Quatsinoporites cranhamii sp. nov., pores are round to elliptical, three per mm, and 130-540 μm diam. Dissepiments consist of narrow, simple septate, hyphae. Neither basidia nor basidiospores are present, but acuminate hymenial cystidia, up to 54 μm in length, are common. The Eocene specimen, Appianoporites vancouverensis sp. nov., has a pore density of six per mm and pores are 130-163 μm in diam. Dissepiments consist of narrow, simple septate, thin-walled hyphae. Neither basidia nor basidiospores are present, but acuminate, thick-walled hymenial cystidia, up to 32 μm in length, are common. The poroid hymenophore is a characteristic of a number of extant basidiomycete taxa, including the Boletales, Polyporales and Hymenochaetales. It is unlikely that the fleshy, ephemeral, terrestrial basidiomata of the Boletales would be preserved in a marine environment, and thus the specimens are interpreted as belonging to basidiomycete lineages, with persistent, leathery or corky basidiomata. The simple septate hyphae, the minute pores and presence of cystidia most closely resemble taxa of the Hymenochaetales. These fossils unequivocally push back the minimum age of homobasidiomycetes and extend their paleogeographical range.
TL;DR: The findings show that the MYRE1-MYRE4 together with MYRE5 are present in two species of Trichoderma, T. atroviride and T. hamatum and that the presence of these motifs could predict co-expression in response to two carbon sources.
Abstract: Mycoparasitism of fungal plant pathogens by Trichoderma species is a complex process that in- volves the production and co-ordinated secretion of cell-wall degrading enzymes. Genes implicated in my- coparasitism by Trichoderma atroviride contain motifs in the promoter region, designated MYRE1-MYRE4, that are proposed to act as binding sites for a global inducer of the mycoparasitic response. The aim of our study was to establish whether these motifs also were present in Trichoderma hamatum and whether the presence of these motifs could predict co-expres- sion when T. hamatum was confronted by a patho- gen. Using a combination of targeted, degenerate and inverse PCR, homologues of the mycoparasitism- related genes ech42 (chit42), prb1 and lam1.3 (xbg1.3-110), which encode an endochitinase, pro- teinase, and b-1,3-glucanase, respectively, were cloned and sequenced from T. hamatum. Alignment of the promoter regions of the three genes revealed identical regions in the chit42 and prb1 promoters, which were 6-9 base pairs in length and conserved in position. Specifically, the regulator y motifs MYRE1-MYRE4 were fully conserved, together with a fifth motif, identified by this research. A substrate as- say designed to investigate the response of these genes from T. harzianum and T. hamatum to a simple carbon source (glycerol) showed that, in contrast to chit42 and prb1, xbg1.3-110 was not expressed. Fur- ther comparison of the expression patterns of these three genes between T. harzianum and T. hamatum using the glycerol substrate assay showed that no
TL;DR: The need to revise many of the concepts usually applied to the classification of members of the Diatrypaceae family is suggested, suggesting that the multisporate asci character has appeared several times during the evolution of the group.
Abstract: The order Diatrypales (Ascomycota) contains one single family, the Diatrypaceae. To obtain insight in the phylogenetic relationships within this family, the complete sequences of the ITS region (ITS1, 5.8S rRNA gene and ITS2) of 53 isolates from the five main genera in the family (Diatrype, Diatrypella, Cryptosphaeria, Eutypa and Eutypella) were determined and aligned for phylogenetic reconstruction. Sequence analysis revealed the presence of tandem repeated motifs 11 nucleotides-long, placed in homologous positions along the ITS1 region. Parsimony analysis established the existence of nine monophyletic groups and one branch with a single isolate of Eutypella quaternata. The phylogenetic relationships established by parsimony analysis did not correlate well with classical taxonomic schemes. None of the five genera included in this study was found to be monophyletic. The genera Diatrype, Eutypa and Cryptosphaeria each were divided into two groups. Isolates of Diatrype flavovirens appeared in a clade separated from the one that grouped Diatrype disciformis and the rest of Diatrype species. The Eutypa strains appeared distributed into two clades, one grouping Eutypa lata and related species (Eutypa armeniacae, Eutypa laevata, Eutypa petrakii), and another with the remaining species of the genus. Eutypella (excluding Eutypella quaternaria) appeared as an unstable monophyletic group, which was lost when the sequence alignment was subjected to neighbor-joining analysis. The genus Diatrypella was not associated with any monophyletic group, suggesting that the multisporate asci character has appeared several times during the evolution of the group. Overall, our study suggests the need to revise many of the concepts usually applied to the classification of members of the family.
TL;DR: The biomass-alginate complex efficiently removed Pb, Zn and Cu from polluted water samples and could be employed either in free or immobilized form as a biosorbent of metal ions in waste water.
Abstract: Thirty-two fungal species were isolated from a polluted watercourse near the Talkha fertilizer plant, Mansoura Province, Egypt. Aspergillus niger, A. flavus, Cunninghamella echinulata and Trichoder...
TL;DR: Experiments show that spiny balls are not chlamydospores because of the absence of nuclei in the structures and quick formation within 3 d in a young colony, and Infection of nematode by the fungus occurs only after the nematodes are immobilized (feeble or dead), probably by a toxin.
Abstract: Nematophagous basidiomycete fungi kill nematodes by trapping, endoparasitizing and pro- ducing toxin. In our studies Coprinus comatus (O.F.Mull. : Fr.) Pers. is found to be a nematode-de- stroying fungus; this fungus immobilizes, kills and uses free-living nematode Panagrellus redivivus Good- ey and root-knot nematode Meloidogyne arenaria Neal. C. comatus produces an unusual structure des- ignated spiny ball. Set on a sporophore-like branch, the spiny ball is a burr-like structure assembled with a large number of tiny tubes. Purified spiny balls ex- hibit moderate nematicidal activity. Experiments show that spiny balls are not chlamydospores because of the absence of nuclei in the structures and quick formation within 3 d in a young colony. Nematodes added to C. comatus cultures on potato-dextrose agar (PDA) and cornmeal agar (CMA) become inactive in hours. Infection of nematodes by the fungus occurs only after the nematodes are immobilized (feeble or dead), probably by a toxin. Electron micrographs il- lustrate that C. comatus infect P. redivivus by produc- ing penetration pegs with which hyphae colonize nematode bodies. An infected nematode is digested and consumed within days and hyphae grow out of the nematode.
TL;DR: The first comprehensive definition of natural groupings in matsutake is presented, infer patterns of migration and propose Eocene origins for the group in western North America by a transfer from an angiosperm-associated ancestor to an increasingly specialized conifer symbiont.
Abstract: Matsutake are commercially important ec- tomycorrhizal basidiomycetes in the genus Tricholo- ma. Despite their importance, the systematics of this species complex have remained elusive and little is known about their origin and biogeography. Using DNA analyses on a worldwide sample of matsutake, we present here the first comprehensive definition of natural groupings in this species complex. We infer patterns of migration and propose Eocene origins for the group in western North America by a transfer from an angiosperm-associated ancestor to an in- creasingly specialized conifer symbiont. From these origins, matsutake appear to have followed migratory routes parallel to those of coniferous hosts. Patterns of vicariance between eastern North America and eastern Asia are resolved and their origins are sug- gested to stem from migration through Beringia. Us- ing an analysis of genetic dissimilarity and geograph- ical distance, we reject both the possibility that mi- gration into Europe and Asia occurred through At- lantic bridges and the connection between matsutake populations in the Mahgrebi Mountains and those from Europe. Instead, African and European matsu- take appear to be the most recent ends of a westward expansion of the domain of these fungi from North
TL;DR: The results suggest that, as suggested in a previous study, Sparassis and Phaeolus form a monophyletic group, which is united by the production of a brown rot.
Abstract: Sparassis species show extensive morphological variation, especially when materials from eastern Asia and Australia are compared with collections from North America and Europe. We have been studying the taxonomy of Sparassis from eastern Asia, North America, Australia and Europe, using both morphological and molecular data. DNA was extracted from 32 recent collections of Sparassis from Australia, Canada, China, Finland, France, Germany, Japan, Switzerland, Thailand, the United Kingdom and the United States. The report of a Sparassis taxon from Australia is the first report of this genus from the Southern Hemisphere. Sequences of nuclear and mitochondrial rDNA and the gene encoding RNA polymerase subunit II (RPB2) were used to examine relationships both within the genus Sparassis and between Sparassis species and other members of the polyporoid clade. Equally weighted parsimony analyses and Bayesian analyses were performed using independent datasets and combined datasets of sequences from different regions. Our results suggest that: (i) Polyporoid fungi producing a brown rot may form a clade; (ii) as suggested in a previous study, Sparassis and Phaeolus form a monophyletic group, which is united by the production of a brown rot, the presence of a bipolar mating system and the frequent habit of growing as a root and butt rot on living trees; (iii) at least seven lineages are within Sparassis, represented by S. spathulata, S. brevipes, S. crispa, S. radicata and three taxa that have not been described, which can be distinguished on the basis of fruiting body structure, presence or absence of clamp connections, presence or absence of cystidia and spore size.
TL;DR: The level of innerspecific morphological plasticity of fruit bodies differs widely between even closely related species, suggesting that morphological transitions occur quite frequently in this fungal group.
Abstract: Morphological, phylogenetic (sequencing of the ribosomal ITS region) and, if applicable, bio- logical (pairings of single-spore testers) species rec- ognition have been used to resolve relationships among 69 collections belonging to the Hymenochae- tales genera Phellinus s.str. and Fomitiporia. The iso- lates originate from a variety of host plants in Europe, North America and Asia. Separate application of rec- ognition modes led to differing results concerning the number of species, geographic distribution and host range. Sole application of morphological criteria was of limited value, especially in taxa exhibiting a wide distribution, both in terms of geographic origin and ecological niche. Relationships of putatively con- specific collections originating from different conti- nents preferably should be resolved by using an in- tegrative approach. In this study, application of a strict morphological approach led to the recognition of seven species. When using molecular and pairing test data, at least 12 species were detectable. Two of them, F. hesleri and F. polymorpha, are described as new. The number of Phellinus s.str. and Fomitiporia species supposed to have Northern Hemispheric or cosmopolitan distribution, when morphological char- acters are applied for species recognition, has been reduced significantly. As firm tendencies within mor- phological species, genetic divergence was more dis- tinct in uniparental than in biparental taxa. In the latter, a strong correlation was observed between phy- logenetic and biological species recognition. Overall length of the ribosomal ITS region clearly separated Phellinus s.str. and Fomitiporia but was of limited val- ue as a diagnostic tool at species level. The level of innerspecific morphological plasticity of fruit bodies differs widely between even closely related species, suggesting that morphological transitions occur quite
TL;DR: A key to nectriaceous species of Neonectria that have Cylindrocarpon anamorphs that lack microconidia and chlamydospores and/or that have a N. mammoidea type perithecial wall anatomy is presented.
Abstract: Neonectria (Hypocreales: Nectriaceae) species having Cylindrocarpon anamorphs that lack microconidia and chlamydospores include: Neo. discophora var. discophora, Neo. discophora var. rubi, stat nov...