White Hyphae Research Articles

Phylogenetic relationships of Nemania plumbea sp. nov. and related taxa based on ribosomal ITS and RPB2 sequences

During a survey fungal diversity of xylariaceous fungi in Thailand, a new Nemania species, N. plumbea, was identified. Nemania plumbea is characterized by soft-textured grey stromata on a persistent mat of white hyphae, pale brown ascospores with a short germ-slit on the more convex side. It also produces a Geniculosporium-like anamorph in culture. In order to evaluate its phylogenetic relationships among related species and genera, ITS-5.8S rDNA and RPB2 were analysed separately and simultaneously. Results from the phylogenetic analyses indicate that there is close phylogenetic association between N. plumbea and N. aenea. A preliminary account into the natural grouping of Xylariaceae based on ITS-5.8S rDNA and RPB2 sequences is also discussed.

New choke diseases and their molecular phylogenetic analysis in Agropyron ciliare var. minus and Agropyron tsukushiense var. transiens

Choke diseases were surveyed in two closely related grass species, Agropyron ciliare var. minus and Agropyron tsukushiense var. transiens, in Shiga Prefecture, Japan. Perithecia and ascospores were not observed in either case. Stromata on A. ciliare var. minus enclosed and sterilized young inflorescences, as in the typical choke symptoms by Epichloë typhina. On the other hand stromata on A. tsukusiense var. transiens thinly covered mature spikes with white epiphyllous hyphae, as in stromata of Ephelis spp. The fungal isolates produced typical Neotyphodium-type conidia. Molecular phylogenetic analyses using the beta-tubulin gene (tubB) indicated that the two Agropyron species are infected with the species grouping into a novel single clade among Epichloë species and they are closely related to a haploid of hybrid Neotyphodium species. The host plant features may be the cause of the differences between stromata of A. ciliare var. minus and A. tsukushiense var.

New choke diseases and their molecular phylogenetic analysis in Agropyron ciliare var. minus and Agropyron tsukushiense var. transiens

Choke diseases were surveyed in two closely related grass species, Agropyron ciliare var. minus and Agropyron tsukushiense var. transiens, in Shiga Prefecture, Japan. Perithecia and ascospores were not observed in either case. Stromata on A. ciliare var. minus enclosed and sterilized young inflorescences, as in the typical choke symptoms by Epichloë typhina. On the other hand stromata on A. tsukusiense var. transiens thinly covered mature spikes with white epiphyllous hyphae, as in stromata of Ephelis spp. The fungal isolates produced typical Neotyphodium-type conidia. Molecular phylogenetic analyses using the beta-tubulin gene (tubB) indicated that the two Agropyron species are infected with the species grouping into a novel single clade among Epichloë species and they are closely related to a haploid of hybrid Neotyphodium species. The host plant features may be the cause of the differences between stromata of A. ciliare var. minus and A. tsukushiense var. transiens.

Simple diagnosis using ethanol immersion of strawberry plants with latent infection by Colletotrichum acutatum, Dendrophoma obscurans, and Fusarium oxysporum f. sp. fragariae

Simple diagnosis by ethanol immersion (SDEI) to detect Glomerella cingulata was used to detect three other fungi that also cause latent infection of strawberry plants. Signs on strawberry leaves with asymptomatic latent infection by Colletotrichum acutatum became visible using SDEI. Salmon-pink conidial masses were produced in the acervuli on the treated leaves 5 days after incubation at 28°C. In the case of Dendrophoma obscurans, pycnidia with amber conidial masses formed 5 days after incubation at 28°C. The pycnidia were observed mainly on the ribs, and conidial masses exuded from the ostiole. These macroscopic conidial masses were similar to those of G. cingulata and C. acutatum. When water was dripped onto a lesion caused by D. obscurans, the pycnidia exuded white filamentous conidial masses, making the distinction of D. obscurans from G. cingulata or C. acutatum. On petioles with latent infection by Fusarium oxysporum f. sp. fragariae, white aerial hyphae grew out from the vascular tissues on the cut surface 3 days after incubation at 28°C and were easily observed by eye or with a loupe. Thus, SDEI was also useful for diagnosing latent infection of strawberry plants by C. acutatum, D. obscurans, and F. oxysporum f. sp. fragariae.

First report of foliar blight in Brassica rapa ssp. chinensis caused by Rhizoctonia solani AG-4

Brassica rapa ssp. chinensis (bok choy) is a vegetable popular in Asia. In July 2003, foliar blight symptoms were first observed on leaves of B. rapa ssp. chinensis at the six- to eight-leaf stage in a field at Jialize Farm, Kunming, Yunnan Province, China. The symptoms appeared as primary lesions consisting of small, circular necrotic spots, 1–3 mm in diameter, accompanied by secondary lesions with large irregular borders. Under high moisture conditions white hyphae appeared on the stems; however, no lesions were observed. Sections (1 × 2 cm) cut from infected stems were surface-sterilized and transferred to potato dextrose agar. Rhizoctonia solani was recovered consistently from this material. Anastomosis group testing revealed that all 13 isolates belonged to AG4 (Sneh & Ogoshi, 1998). Pathogenicity tests with a hyphal-tip isolate were carried out using B. rapa ssp. chinensis in two controlled-environment cabinets (one set at 25°C, 16-h day and the other at 16°C, 8-h night cycle), one utilizing seeds and the other utilizing plants at the six-leaf stage. Both were planted in 3-week-old inoculated cornmeal-sand medium. A high level of humidity was maintained by placing a pan of water in the bottom of the incubators. Control plants were planted in uninoculated cornmeal-sand medium. After 1 week emerging seedlings exhibited both leaf and stem necrosis near the apex. On the 6-week-old plants, foliar blight of young leaves was more severe than those observed on the older leaves. After 2 weeks, grey-white hyphae appeared on the stem but no lesions were present. Control plants did not develop symptoms. Rhizoctonia solani AG4 was re-isolated from the inoculated plants. Rhizoctonia foliar blight of cabbage (Brassica oleracea var. capitata) has been reported in New York State, USA (Abawi & Martin, 1985). However, this is the first published report of foliar blight of bok choy (Brassica rapa ssp. chinensis) caused by R. solani AG4. The Yunnan Nature Science Fund supported this study.

Different temporal and spatial expression of two hydrophobin-encoding genes of the edible mushroom Agaricus bisporus.

In a search for genes that are only expressed in fruit bodies of the basidiomycete Agaricus bisporus, two cDNAs, hypA and hypB that encode hydrophobins have been isolated previously. In this study, the structure of hypB is resolved and it is shown that the two genes are differentially expressed, indicating that the encoded hydrophobins serve different functions in A. bisporus mushrooms. hypB encodes a polypeptide (HYPB) of 119 aa that shows little sequence identity with HYPA apart from the characteristic arrangement of eight cysteines found exclusively in hydrophobins. The temporal and spatial expression of the two hydrophobin-encoding genes during fruit body development was compared using Northern analysis and in situ hybridization. Accumulation of hypA mRNA was found in tissue fractions consisting of undifferentiated white hyphae. In situ hybridization showed that the highest hypA mRNA levels are not found in the outermost cell layers of the pileipellis but in the cell layers adjacent to that. The highest level of expression of hypB occurs early in development when the primordium differentiates into densely packed, randomly oriented cap hyphae and loosely packed, vertically oriented stipe hyphae. In mature mushrooms, a strong accumulation of hypB transcripts was found only in the transitional zone between cap and stipe tissue, demonstrating that transcription regulation of hypB is clearly distinct from hypA.

The role of morphogenetic cell death in the histogenesis of the mycelial cord of Agaricus bisporus and in the development of macrofungi

Hyphal growth of the white button mushroom Agaricus bisporus on spawn grains and compost is typically vegetative. Hyphae are loosely arranged, in contrast to the organized texture in tissues, and needle-like calcium oxalate crystals are frequently present on the surface of vegetative hyphae. The mycelial cord is the first well-organized tissue of the fruiting mycelium; it is surrounded by fluffy white hyphae that grow vegetatively. The hyphae of the cord are held together through a semi-fluid medium, the extracellular matrix, which aids in creating a three-dimensional pseudoparenchymatous structure. The matrix material seems to be secreted into the extracellular environment by specifically differentiated cells, but the vegetatively growing hyphae of A. bisporus initially exploit a different mechanism in the production of matrix which involves a type of cell death different from cell necrosis. This primary matrix production leads to the formation of minute cord tissues in which oxalate crystals are no longer present. Once the hyphal cells of A. bisporus pass the threshold from a vegetative form into organized structures, they become differentiated and self-maintaining in the production of the extracellular matrix material. Morphogenetic cell death has been observed before in A. bisporus development and here we show that it occurs in various species of macrofungi: a mucoid zone of the pileipellis typically found in developing fruit bodies of Psilocybe and Panaeolus spp. contains numerous, dying or dead hyphal cells which show ultrastructural features comparable to those observed during the mycelial cord formation of A. bisporus. Studies performed using specimens of Stropharia rugoso-annulata, Coprinus domesticus, Psathyrella candolleana, Tremella mesenterica, Otidea onotica and Peziza ostracoderma in representative growth stages revealed supporting evidence for the view that morphogenetic cell death plays a key role at different stages during the development of fungal fruit bodies. This phenomenon may be related to the programmed cell death occurring in developing plants and animals.

Hyphal regeneration and histogenesis in Agaricus bisporus

Growing fruit bodies of Agaricus bisporus and Amanita muscaria responded with regenerating white hyphae to cell and tissue injuries caused by intrapileal needle insertion and leucofuchsin injection. We point out reserve cells as a possible source of regenerating hyphae in the wound repair. Such reserve cells were not found in the partial veil and in the surface covering. Damage of the partial veil remained unrepaired and caused lamellar dysplasia. Hydrophilic, somatic tissues reacted immediately and strongly with leucofuchsin, whereas hyphae of the surface covering and partial veil showed a delayed and weak reaction. We explain this by the presence of an extracellular matrix, which consists of hydrophilic mucilaginous substances around tissue-forming hyphae. Transmission and scanning electron microscopical studies revealed that white hyphae were deprived of such matrix material. We conclude that for fungal tissue formation the hyphae have to be capable of producing a substantial amount of extracellular matrix material beyond the cell wall.

Characteristics of Peridermiumharknessii in axenic culture

Axenic cultures of Peridermiumharknessii J.P Moore developed white aerial hyphae, orange callus-like growth, and white mycelium colonies as successive vegetative forms when isolated from explants from infected mature field-grown Pinusponderosa Dougl. ex. P. Laws & C. Laws. Expiants (small cubes of gall phloem tissue) were collected from March through August 1988 and 1989 in eastern Nebraska and northern and western North Dakota. By 20 days after plating, white hyphae appeared to originate from immature aeciospores. By 45 days, friable orange callus-like growth appeared on many explants from beneath the white hyphae and eventually overgrew the latter. Orange callus colonies consisted mostly of single-celled vesicular cells, which seemed to originate from aeciospore initials. The larger vesicular cells were similar in size to aeciospores, contained orange subcellular globules, and occasionally had surface ornamentation similar to that of aeciospores. After 60 days, white mycelium colonies grew as sectors within and at the edges of many orange callus cultures. The colonies appeared to originate as appendages of thick-walled hyphal strands of orange callus and macroscopically consisted of compact masses of thin-walled hyaline hyphae arising from a stroma. If not transferred to fresh medium, orange callus would frequently convert to white mycelium colonies. No change in the morphology of white mycelium colonies was observed. Only mineral salt media supplemented with peptone, soytone, or a mixture of yeast extract, sucrose, and glucose sustained fungal growth apart from the host tissue. Both orange callus and white mycelium colonies grew over a temperature range of 5–35 °C, and revealed similar staining patterns in 12 of 14 isozymes to those of Peridermiumharknessii aeciospores when analyzed with starch gel electrophoresis.

Intergeneric hybridization betweenMonascus anka andAspergillus oryzae by protoplast fusion

To breed industrially useful strains of a slow-growing, red-pigment-producing strain ofMonascus anka, protoplasts ofM. anka MAK1 (arg) andAspergillus oryzae AOK1 (met, thr) were fused. A mixture of protoplasts prepared from mycelia ofM. anka MAK1 treated with 2% Usukizyme and ofA. oryzae AOK1 treated with 2% Usukizyme and 0.2% NovoZym 234 was incubated with 30% (w/v) polyethylene glycol no. 6000. Heterokaryon fusants complementing the auxotrophies of both mutants were isolated on minimal medium, but segregated into red (MAK1) and white (AOK1) sectors after being cultured on a complete medium. After irradiation with UV light, the fusants gave stable heterozygous diploids that formed long white hyphae. These diploids, which had twice as much DNA in the nucleus as their parents, grew more rapidly than the parent strain YZT1, and produced ethanol earlier than the parents. Production of amylase, protease, and kojic acid by the fusants was intermediate in amount between that of the two parents.

Leaf blight of day lily caused by Aureobasidium microstictum (Bubak) W.B. Cooke.

Brown spots and yellow stripes were observed on leaves of Hemerocallis fulva var. kwanso at the herbal garden of Kyoto Prefectural Research Institute of Agriculture in Ayabe in the late June of 1985. In the beginning, small brown spots appeared on both sides of the leaves and then bright yellow stripes occurred and brownings expanded gradually from the leaf tips. These symptoms had been observed until mid-November. No pathogen was generally observed on diseased leaves, while acervuli composed of the tightly interwoven hyphae were formed on host plants in moist chamber. Conidiogenous cells were clavate to subcylindrical. Conidia were blastic, ellipsoidal to fusoid, hyaline, smooth, one-celled. Inoculation tests indicated that isolates were pathogenic on injured leaves of H. fulva var. kwanso, H. fulva var. disticha, and H. fulva var. fulva. An isolate from naturally infected H. fulva var. disticha showed the same pathogenicity as those from H. fulva var. kwanso. On PDA medium, single conidium isolates formed creamy and yeastlike colonies at first, then after formed white hyphae, and eventually turned dark brown to black in color. Growth on PSA medium occurred in the range from 8 to 30C and optimum growth at between 20 and 24C. Conidia formed on PDA medium were blastic, ellipsoidal to fusoid, hyaline, smooth, one-celled. Secondary conidia were formed and yeastlike growth appeared. On the basis of its morphological characteristics and pathogenicity on the plants of the genus Hemerocallis, the present fungus was identified as Aureobasidium microstictum (Bubak) W.B. Cooke, and a common name, leaf blight, was proposed.

Two New Gasteromycetes

During the summer of 1938 the author collected a number of soil s-amples near near East Lansing, Michigan, to determine whether or not Gasterella lutophila Zeller & Walker could be found. The results of that study may be found in a previous paper.1 In addition to G. lutophila, fruiting-bodies of another fungus developed during the last of July, 1938, on one of the soil samples that came from a particular wood-lot. On October 11 samples of soil were obtained in triplicate from the same spot from which the earlier sample had been taken. Fruiting-bodies of this same new fungus were first observed on one of these collections on October 29. On a second lot of the soil fruiting-bodies did not appear until November 7, 1938. The methods of study were the same as those employed for Gasterella lutophila. Because of its similarity in many particulars to Gasterella the writer suggests the generic name Gasterellopsis for this new fungus. The basidiocarps of Gasterellopsis were first visible on the surface of the soil in from 18 to 26 days after the soil was collected and prepared. The first sign of the fungus was the appearance of minute wefts of loose, white hyphae. These developed into the mature fruiting-bodies in four to six days. Most of the specimens developed on the surface of the soil, but occasionally a specimen formed just below the surface and pushed the soil particles aside as it grew. A scarcity of specimens between the youngest and mature stages prevented discovery of the details of development of the glebal