Mature Basidiocarps Research Articles

Mid-Infrared Spectroscopic Study of Cultivating Medicinal Fungi Ganoderma: Composition, Development, and Strain Variability of Basidiocarps.

Attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy was proposed for rapid, versatile, and non-invasive screening of Ganoderma basidiocarps to assess their potential for specific applications. Fifteen species and strains of this fungus were selected for analysis, and fine sections at different parts of young and mature basidiocarps were obtained. The spectra of fungal samples showed significant differences interpreted in terms of biochemical composition using characteristic bands of proteins, polysaccharides, lipids, and triterpenoids. Obviously, for the transverse sections in trama, especially in the basal part, the most intense bands at 950-1200 cm-1 corresponded to polysaccharide vibrations, while for the superficial sections, the bands of carbonyl and aliphatic groups of triterpenoids at 1310-1470, 1550-1740, and 2850-2980 cm-1 predominated. The pilei, especially hymenium tubes, apparently contained more proteins than the bases and stipes, as evidenced by the intense bands of amide vibrations at 1648 and 1545-1550 cm-1. The specificity of the Ganoderma basidiocarp is a densely pigmented surface layer rich in triterpenoids, as proved by ATR-FTIR spectroscopy. The spectral differences corresponding to the specificity of the triterpenoid composition may indicate the prospects of individual strains and species of this genus for cultivation and further use in food, cosmetics, or medicine.

Bioremediation of aflatoxin B1-contaminated maize by king oyster mushroom (Pleurotus eryngii).

Aflatoxin B1 (AFB1) is the most harmful mycotoxin that occurs as natural contaminant of agricultural commodities, particularly maize. Practical solutions for detoxification of contaminated staples and reduction of agricultural wastes are scarce. We investigated the capability of the white-rot and edible fungus Plerotus eryngii (king oyster mushroom) to degrade AFB1 both in vitro and in a laboratory-scale mushroom cultivation, using a substrate similar to that routinely used in mushroom farms. In malt extract broth, degradation of AFB1 (500 ng/mL) by nine isolates of P. eryngii ranged from 81 to 99% after 10 days growth, and reached 100% for all isolates after 30 days. The growth of P. eryngii on solid medium (malt extract-agar, MEA) was significantly reduced at concentrations of AFB1 500 ng/mL or higher. However, the addition of 5% wheat straw to the culture medium increased the tolerance of P. eryngii to AFB1 and no inhibition was observed at a AFB1 content of 500 ng/mL; degradation of AFB1 in MEA supplemented with 5% wheat straw and 2.5% (w/v) maize flour was 71–94% after 30 days of growth. Further, AFB1 degradation by P. eryngii strain ITEM 13681 was tested in a laboratory-scale mushroom cultivation. The mushroom growth medium contained 25% (w/w) of maize spiked with AFB1 to the final content of 128 μg/kg. Pleurotus eryngii degraded up to 86% of the AFB1 in 28 days, with no significant reduction of either biological efficiency or mushroom yield. Neither the biomass produced on the mushroom substrate nor the mature basidiocarps contained detectable levels of AFB1 or its metabolite aflatoxicol, thus ruling out the translocation of these toxins through the fungal thallus. These findings make a contribution towards the development of a novel technology for remediation of AFB1- contaminated corn through the exploitation of the degradative capability of P. eryngii and its bioconversion into high nutritional value material intended for feed production.

Transcriptomic analysis of basidiocarp development in Ustilago maydis (DC) Cda.

Previously, we demonstrated that when Ustilago maydis (DC) Cda., a phytopathogenic basidiomycete and the causal agent of corn smut, is grown in the vicinity of maize embryogenic calli in a medium supplemented with the herbicide Dicamba, it developed gastroid-like basidiocarps. To elucidate the molecular mechanisms involved in the basidiocarp development by the fungus, we proceeded to analyze the transcriptome of the process, identifying a total of 2002 and 1064 differentially expressed genes at two developmental stages, young and mature basidiocarps, respectively. Function of these genes was analyzed with the use of different databases. MIPS analysis revealed that in the stage of young basidiocarp, among the ca. two thousand differentially expressed genes, there were some previously described for basidiocarp development in other fungal species. Additional elements that operated at this stage included, among others, genes encoding the transcription factors FOXO3, MIG3, PRO1, TEC1, copper and MFS transporters, and cytochromes P450. During mature basidiocarp development, important up-regulated genes included those encoding hydrophobins, laccases, and ferric reductase (FRE/NOX). The demonstration that a mapkk mutant was unable to form basidiocarps, indicated the importance of the MAPK signaling pathway in this developmental process.

Evaluation of casing variables for cultivation of Agaricusbisporus strain U3 in Punjab, India

Casing is an important step during cultivation of button mushroom. It promotes a shift of vegetative mycelium to form pinheads leading to mature basidiocarps. Therefore, An experiment was planned at Punjab Agricultural University, Ludhiana in which farm yard manure (FYM), biogas slurry (BS), burnt rice husk (BRH), spent compost (SC), coir pith (CP) and sandy soil (SS) were used in six combinations to evaluate their impact on yield of Agaricusbisporus strain U3. Casing mixtures were analyzed for the moisture, water holding capacity (WHC), bulk density, pH, electrical conductivity (EC) and mineral analysis. The moisture content of casing mixtures ranged between 33 to 56.3% with maximum in FYM+CP (1:1) and FYM+BS (1:1) which results in more water holding capacity with 160% and 100% for FYM+CP (1:1) and FYM+BS (1:1) respectively. The bulk density of different casing mixtures ranged between 33.3 to 83.3% and maximum for FYM+BS as well as the control FYM+SS (4:1). No significant variation in pH of casing mixture was observed while EC was significantly higher in FYM+BS (1:1) with 1.7 mmhos cm-1. Microbial count of different casing mixtures was between 3.0-5.7×105 which was statistically non-significant with respect to casing mixtures. A mixture of FYM+BRH (1:1) gave maximum yield of 15.1 kg with heavy fruit bodies. Number of fruiting bodies in casing mixture FYM+BRH (1:1) were 31.4, 26.4, 148.1,31.4 and 8.1 percent higher over FYM+CP (1:1), FYM+SC (1:1), FYM+BS (1:1), FYM and FYM+SS (4:1,control), respectively. The casing mixture FYM+BRH (1:1) with higher number of fruiting bodies with maximum fruiting bodies weight was the best alternate in mushroom growing industry.

Bioprospecting optimal phenology for bioactive molecules in native golden yellow Pleurotus citrinopileatus Singer

ObjectiveTo bioprospect optimal phenological phases as source of novel molecules from native golden yellow Pleurotus citrinopileatus across four phenologies in both aqueous and ethanol extracts, and identify novel molecules responsible for these activities. MethodsStandard qualitative assay, Folin–Ciocalteu assay; aluminium chloride spectrophotometric, 2, 2-diphenyl-1-picrylhydrazyl, 2, 2′-azinobis (3-ethylbenzothiazoline-6-suslfonic acid, ferricyanide reducing antioxidant power were used to determine total flavonoid, polyphenols, radical scavenging, and reducing power. Spectrophotometric methods were used for lycopene, β-carotene, and total carotenoids, while liquid chromatography quadrupole time of flight mass spectrometry was used for identification and comparative quantitation of polyphenols and flavonoids across the four phenological states. ChemSpider™ database was used for the identification of compounds based on their empirical formula, accurate mass and literature review of previously reported compounds in mushroom. ResultsPrimordial phases exhibited higher contents of secondary metabolites than mature basidiocarps. Polyphenols content differed across physiological phases with primordials exhibiting significant high contents (P<0.05) [(13.803 ± 0.797) mg gallic acid equivalent/g dry weight]. Distribution of total flavonoids was significantly different (P<0.05) across physiological states and ranged from (3.311 ± 0.730) to (14.824 ± 0.890) mg quercetin equivalent g dry weight. Ten polyphenol acids and seven flavonoids compounds identified varied across these phases with primordials exhibiting relatively high peak areas. Total antioxidant activities showed a positive correlation with total polyphenols (r=0.969; P<0.05) and total flavonoids (r=0.960; P<0.05) across these phenologies. ConclusionsThese findings provide evidence that primordials of golden yellow mushroom as opposed to their fruiting bodies are potent sources of bioactive health molecules.

Basidiocarp Production of &amp;lt;i&amp;gt;Stropharia melanosperma&amp;lt;/i&amp;gt; (Bull.) Gillet in Nutrient Agar Media

The present work studies the fruiting body production of S. melanosperma (Bull.) Gillet using pairing test in nutrient agar media. Fourteen monokaryotic strains from single fruit body were chosen for the pairing test. Ninety-one crossings were made and fruit bodies were found in 20 crossings. Fully mature basidiocarps were produced in a ring-like fashion in one or both colonies. The patterns of the fruit body production in crossing single spore isolates are similar to those common in heterothallic tetrapolar species. The conducted work shows that S. melanosperma can serve as a model organism for the study of developmental processes in the basidiomycetes.

Foraging of Psilocybe basidiocarps by the leaf-cutting ant Acromyrmex lobicornis in Santa Fé, Argentina

BackgroundIt is generally accepted that material collected by leaf-cutting ants of the genus Acromyrmex consists solely of plant matter, which is used in the nest as substrate for a symbiotic fungus providing nutrition to the ants. There is only one previous report of any leaf-cutting ant foraging directly on fungal basidiocarps.FindingsBasidiocarps of Psilocybe coprophila growing on cow dung were actively collected by workers of Acromyrmex lobicornis in Santa Fé province, Argentina. During this behaviour the ants displayed typical signals of recognition and continuously recruited other foragers to the task. Basidiocarps of different stages of maturity were being transported into the nest by particular groups of workers, while other workers collected plant material.ConclusionsThe collection of mature basidiocarps with viable spores by leaf-cutting ants in nature adds substance to theories relating to the origin of fungiculture in these highly specialized social insects.Electronic supplementary materialThe online version of this article (doi:10.1186/2193-1801-2-254) contains supplementary material, which is available to authorized users.

First Report of Syzygites megalocarpus (Mucorales) Web Mold on the Commercial Portabella Button Mushroom Agaricus bisporus in North America.

Agaricus bisporus (Lange) Imbach mushrooms, which are cultivated commercially under environmentally controlled conditions, are the most valuable crop in Pennsylvania. In August 2011, we first observed a mucoraceous mold colonizing primordia and mature basidiocarps of a new brown portabella strain of A. bisporus at two commercial mushroom farms in Chester County, PA. This strain is a hybrid between a commercial strain producing white basidiocarps and a brown wild type isolate of A. bisporus. Mushrooms mature in weekly "flushes". By third flush, 25% of the production surface at both farms was colonized by a fast growing mycelium that was initially white, subsequently yellow to golden brown, and finally grayish. Mushrooms colonized by the mold showed pitting, discoloration, and necrosis. Two pure cultures of the mold were obtained by the hyphal tip method from mature, necrotic basidiocarps at each farm. These isolates were accessioned in the ARS Culture Collection (NRRL, Peoria, IL) as NRRL 54814 to 54815 and 54818 to 54819. The cultures produced abundant aerial sporangiophores that branched dichotomously on potato dextrose agar. Light microscopic examination revealed that each branch terminated in a globose, multispored sporangium with a conspicuous columella. Individual cultures of NRRL 54818 and 54819 produced large (175 to 250 × 200 to 250 μm), barrel-shaped, dark brown to black zygosporangia between opposed suspensors, indicating they were homothallic. Morphological and cultural characteristics of the mold matched the description of Syzygites megalocarpus (3), a member of the Mucorales reported to colonize diverse, mostly fleshy basidiomycetes (2), including cultivated matsutake (Tricholoma matsutake) in Korea (1). Molecular phylogenetic confirmation of the morphological identification was obtained by PCR amplifying and sequencing domains D1 and D2 at the 5' end of the nuclear ribosomal large subunit (LSU rDNA). The four isolates shared an identical LSU rDNA allele. A search of the NCBI nucleotide database, using a partial LSU rDNA sequence from NRRL 54814 as the BLAST query, revealed that it shared 99.5% identity with AF157216.1, a reference isolate of S. megalocarpus NRRL 6288 (3). To assess whether cultures of S. megalocarpus could induce the disease, caps of portabella and white button mushrooms were inoculated with 3.7 × 106 sporangiospores. When incubated in moist chambers at 21 to 22°C with a 12-h photoperiod, disease symptoms developed in 2 to 3 days on portabella that included discoloration and pitting at the site of inoculation. S. megalocarpus was reisolated from the symptomatic mushrooms and produced a colony identical to the original. By comparison, white button mushrooms inoculated with S. megalocarpus, using the same method, only showed minor pitting and discoloration. Disease symptoms were not observed on mushrooms inoculated with water as a negative control. Although development of new commercial varieties derived using "wild" genetically diverse stocks is an effective way to introduce desirable traits into cultivated mushrooms, it carries the risk of introducing new diseases into the industry.

Identification and Distribution of Fungi Associated with Fairy Rings on Golf Putting Greens.

Traditional methods for identification of fairy ring fungi rely on the morphology of mature basidiocarps, which are ephemeral and often do not reach maturity on golf greens due to management practices. From 2007 to 2009, basidiocarps and soil samples were collected from 15 hybrid bermudagrass and 30 bentgrass greens exhibiting fairy ring symptoms in California, Florida, Hawaii, Illinois, Oklahoma, North Caroline, South Carolina, and Wisconsin. Genomic DNA was extracted from 122 unknown samples. Extractions were made from mycelium isolated from puffball or mushroom tissue, from mycelium isolated from a soil block, or through direct DNA extraction from infested soil. DNA also was extracted from 16 reference isolates. The internal transcribed spacer (ITS) region of ribosomal DNA was amplified and sequenced using the basidiomycete-specific primer sets ITS1f/ITS4b and Basid0001/2R. Phylogenetic trees were constructed with the neighborjoining algorithm, with nodes evaluated by bootstrap analysis. Most samples grouped into one of three clades corresponding to species within the family Lycoperdaceae: Arachnion album, Bovista dermoxantha, and Vascellum curtisii. Although over 60 different basidiomycetes have been associated with fairy rings in turfgrasses, relatively few species were found on golf putting greens in this study. Presently, DNA sequencing may be the most efficient method for attempting speciation of fairy ring fungi from infested soil.

Growth Characterization and Triterpenoid Derivatives Quantification of Ganoderma spp. Using HPLC

Mycelium of Ganoderma lucidum (W.Curt.:Fr.) Lloyd grew on the surface of molasses to form mycelial mats after about 12 days. When the mycelial mats became older, the color changed to a darker hue and wrinkled. It took about 9 days for the mycelium of G. tsugae Murrill to cover the whole surface of the molasses. Mycelial mats of G. tsugae were soft, and the old mycelia turned to yellow in color. Harvesting three pieces of mycelial mats of G. lucidum was enough to get 0.96 g of dried biomass. For G. tsugae, the mycelial mats were lighter. On wheat grains, the mycelium of G. lucidum needed 20 days to permeate throughout the grains. The mycelium of G. tsugae needed only 15 days. Both Ganoderma species produced primodia for approximately 65 days, and the mature basidiocarps were formed in about 100 days. The pH of extracts from both fungi became less acidic when harvested after longer periods. All the separation spots of the samples had an Rf value below 0.92. The TLC method detected the presence of triterpenoids in the extract. The different concentrations of thymol salt were used to obtain the standard curve through HPLC method. The values of triterpenoid concentrations, which refer to the peaks as P1, P2, P3, P4, P5, and P6 in the samples, were calculated based on this standard curve. P1, was obtained in every stage of incubation. P3 and P6 were detected only in the fruiting body, whereas P2, P3, P4 were the major triterpenoids of the mycelium. The highest triterpenoid production was found after 110 days; the fruiting body stage of G. tsugae is P5 with 1212.00 μg/mL. G. lucidum showed triterpenoid concentration and derivatives six times higher than G. tsugae.

Indole-3-Acetic Acid, Glucose, and Inoculum Influence the Formation and Distribution of Basidiocarps of Pholiota malicola in Culture

Combinations of light, glucose, 10-4 or 10-3 M indole-3-acetic acid (IAA), and the developmental stage of the inoculum influenced the growth in culture of Pholiota malicola. Vegetative inoculum formed basidiocarps on potato glucose agar (PDA) only with 3 or 4%, and not with 1 or 2% glucose unless IAA was added. In the light on 2% glucose in PDA, using either whole or parts of immature or mature basidiocarps as inoculum, basidiocarps formed and IAA increased their size and numbers. When the cap was used as inoculum its orientation, pileus up or down, determined whether the basidiocarps formed were solitary, in a cluster or scattered. In the dark using all of the aforementioned types of inoculum, IAA promoted the growth of a mass of vegetative mycelium at the inoculation point and enlargement of carpophore parts, but new basidiocarps did not develop.

Indole-3-acetic acid, glucose, and inoculum influence the formation and distribution of basidiocarps of Pholiota malicola in culture

Combinations of light, glucose, 10-4 or 10-3 M indole-3-acetic acid (IAA), and the developmental stage of the inoculum influenced the growth in culture of Pholiota malicola. Vegetative inoculum formed basidiocarps on potato glucose agar (PDA) only with 3 or 4%, and not with 1 or 2% glucose unless IAA was added. In the light on 2% glucose in PDA, using either whole or parts of immature or mature basidiocarps as inoculum, basidiocarps formed and IAA increased their size and numbers. When the cap was used as inoculum its orientation, pileus up or down, determined whether the basidiocarps formed were solitary, in a cluster or scattered. In the dark using all of the aforementioned types of inoculum, IAA promoted the growth of a mass of vegetative mycelium at the inoculation point and enlargement of carpophore parts, but new basidiocarps did not develop.

Effects of Culture Conditions on Mycelial Growth and Luminescence inPanellus Stypticus

A pure culture of Panellus stypticus was isolated from a mature basidiocarp and studied for its growth and luminescence abilities under various environmental and nutritional conditions. The culture...

Effects of Culture Conditions on Mycelial Growth and Luminescence in Panellus stypticus

A pure culture of Panellus stypticus was isolated from a mature basidiocarp and studied for its growth and luminescence abilities under various environmental and nutritional conditions. The culture was non-luminous growing submerged in defined liquid media with or without agitation. After a two- to three-day lag period on solid substrata, luminescence increased exponentially with a doubling time of 4 hours while the increase in colony radial growth was linear. On solid substrata, growth and total light emission were strongly correlated under most conditions studied. Optimal conditions included darkness; 28 C; pH 3.8; glucose, maltose, trehalose, cellobiose or pectin as carbon source; and ammonia or asparagine as nitrogen source. Growth and luminescence were inhibited by ambient fluorescent light. Dark-grown colonies were brightest in the center while light-grown colonies were brightest at the periphery. Cultures hydrolyzed starch and produced an extracellular phenoloxidase. Conditions for production of luminescent basidiocarps by this culture are described.

Widespread haploidy in monokaryotic cells of mature basidiocarps of Armillaria bulbosa, a member of the Armillaria mellea complex

Fluorescence microspectrophotometric measurements of 4′, 6-diamidino-2-phenylindole-stained DNA in 12 nuclear cycle stages of Armillaria bulbosa favor a two diploidization-two haploidization life cycle hypothesis for this species. Measurements of gill trama, pileus hyphae, and stipe hyphae indicate that the monokaryotic nuclei of these basidiocarp tissues are all haploid. Because the haploid basidiocarp presumably develops from an earlier diploid stage, it is considered likely that the haploidization leading to the production of the basidiocarp results in a genetic mosaic.

Trimorphomyces: a New Genus in the Tremellaceae

Trimorphomyces Bandoni and Oberw. gen. nov. (Tremellaceae) includes a single species, T. papilionaceus Bandoni and Oberw. sp. nov., which parasitizes Arthrinium sphaerospermum Fckl. The sporocarps are mainly or entirely conidial at first; conidia and basidia are mixed in mature basidiocarps. The basidia are cruciately-septate, stalked. Basidiospores germinate by repetition or by budding to form a haploid yeast phase. Blastic conidia are formed successively; terminal pairs develop synchronously and conjugate before release. The conidia are H-shaped and dikaryotic. The dikaryotic conidia germinate by forming paired buds and a dikaryotic yeast phase is initiated. Dikaryotic yeast cells are produced in the same manner as the parental conidia and are released as H-shaped, conjugated pairs. In the presence of Arthrinium sphaerospermum hyphae, dikaryotic conidia or dikaryotic yeast cells germinate by hyphal and haustorial formation.

Conidiobolus Thromboides Isolated in Maryland

(1976). Conidiobolus Thromboides Isolated in Maryland. Mycologia: Vol. 68, No. 4, pp. 939-942.

Basidiocarp Formation by Laccaria laccata in Agar Culture

Many Basidiomycetes have been known to be inhabitants of both fields and woodland soils, but the direct isolation from soils of these fungi that fruit on common mycological media has been infrequently reported. Goos (1960) reported the formation of fruiting bodies in culture by four Basidiomycetes that were isolated from soil. They were Pholiota marginata (Fr.) Quel., Irpex lacteus (Fr.) Fr., Schizophyllum commune Fr. and Pellicularia sp. In exploring the microflora of Maryland soils, we obtained a single isolate which produces well-formed fertile basidiocarps in agar culture. It was identified as Laccaria laccata (Scop. ex Fr.) Berk. & Broome according to Singer (1967) and Singer and Moser ( 1965). Since the production of fruiting bodies on agar media is a significant contribution toward study of the nutritional requirements, morphogenesis and genetics of this fungus, it is reported herein. A garden soil sample was collected in College Park, Maryland, in August 1972. The sample was taken to the laboratory and heat-treated for 30 min at 65 C. A dilution plate series was set up using lactose-peptone agar and the plates were incubated at 24 C. After several weeks a stromalike structure was formed in one plate and it was transferred to a rabbit food agar plate. Mature basidiocarps were later observed on inoculation blocks transferred from the rabbit food agar plate to the same medium in flasks and incubated in diurnal alternation of darkness and light at room temperature. The isolate is able to grow on a variety of common mycological media. Mycelial growth took place over a range of 10-45 C with the optimum of 26-37 C. An unidentified conidial state was found in the cultures grown on all the agar media tested. This imperfect state appears to be holoblastic, with hyaline unicellular conidia borne singly or in clusters on multiple random to multiple synchronous conidiogenous cells (FIG. 1). The globose conidia were formed and germinated at 20-45 C. They measured 8-11 im in diam. A clamp connection was observed at the first septum of the germ tube emerging from germinating conidia, and subsequently at most septa of the mycelium ( FIG. 2). Basidiospores of L. laccata have never germinated on laboratory media (Fries, 1966; Stack et al., 1975). Our 211

Typhula Erythropus: II. Sclerotial Germination and Basidiocarp Production

SUMMARY The influence of physical and nutritional factors on sclerotial germination and basidiocarp formation in Typhula erythropus was studied. Sclerotia produced in culture at 10-15 C germinated readily (carpogenically) when incubated on water agar at 4-i0 C. Sclerotia grown to maturity at 4 C did not germinate unless activated while turgid by treatment at 15-20 C for 10-14 da. Viability was reduced by freezing or drying at 20 C, but was not affected by washing or by cold storage for up to 21 mo. Basidiocarps arose in culture from sclerotia, inoculation plugs, and directly from the colonial surface. Development was arbitrarily divided into four morphological stages, and the expansion of the fructification approximated that process in agarics. The range of temperature for basidiocarp development from sclerotia was 4-10 C and 15 C for fructifications arising from the colony. Hymenial formation usually did not occur at 15 C or above or in darkness. Fruit bodies were positively phototropic. Mature basidiocarps were present 6-10 da after initiation and continued to sporulate for 10-15 da under favorable conditions. The optimum pH for fruiting from the colony was near pH 6. Maximum basidiocarp production occurred on low-nutrient media and at a C/N ratio of 19:1. Thiamine was required for mycelial growth and basidocarp formation. Several taxonomic characters were studied for their stability under varying conditions. Basidiospore dimensions were consistent, 5.5-7.5 X 2.43.6 Am. Basidiocarp coloration and proportions remained stable under most conditions, with stalk length and head length and width increasing with age.

Meiosis in Coprinus. V. The role of light on basidiocarp initiation, mitosis, and hymenium differentiation in Coprinus lagopus

Primordial bud formation in Coprinus lagopus is strictly light dependent, but only [Formula: see text]exposure to light is required. However, continued exposure to light is mandatory for further development and hymenium differentiation into a mature basidiocarp. Without light, the stipe of the primordial bud elongates as if the basidiocarp is maturing and the primordial bud eventually aborts. The optimum light intensity is less than 1 ft-c at a wavelength of 410–450 nm. It is possible that cap and stipe are initiated by the same stimulus, but further development of each is under different controls. The former is light dependent whereas the latter is not.The primordial bud development was studied at daily intervals for 3 days until meiosis started and their structural differentiations were studied by paraffin section and squash preparations. The cap of the primordial bud has three zones: the veil, the hymenium, and the stipe. The veil cells are large and multinucleate and lack clamp connections. The stipe includes a central column of dikaryotic hyphae and a cortex of giant multinucleate cells. The hymenium contains only dikaryotic hyphae, which later develop into basidia, cystidia, and medullar cells. The gill development is started by structural organization of dikaryotic hyphae into dome-shaped ridges, which is followed by disintegration of cells surrounding these ridges to form gills. The gill expansion is also light dependent.When the primordial buds were exposed to light, there was a thrust of mitotic activity. Mitotic metaphase, anaphase, and telophase configurations were clearly demonstrated.