Effects of high-temperature treatment on two essential light processes and an intervening dark process in photoinduced pileus primordium formation of a basidiomycete,Favolus arcularius

The photoinduced formation of pileus primordia inFavolus arcularius involves two essential light processes and an inserting dark process. The nature of these elementary proceses in epileate stipes was examined by the use of high temperature under a 1-h light-7-h dark-continuous light regimen. Epileate stipes were exposed to a temperature treatment of 37°C for 15 min after the beginning of pileus primordium formation, which disrupted the photomorphogenetic progress without any after-effects. When high temperature was applied in the first light process or the early phase of the dark process, it completely voided the established career. A temperature-sensitive key dark reaction may have occurred in the period of 0–2 h. When high temperature was applied during the late phase of the dark period, it caused only a delay in pileus primordium, formation, suggesting that the high temperature might only retard the progression of the dark morphogenetic reaction in this period. In addition, the early phase of the second light process was effectively disrupted by the use of high temperature, but sensitivity to high temperature gradually decreased with the progress of pileus differentiation.     

Cultural properties of a luminous mushroom,Mycena chlorophos

Cultural conditions on mycelial growth and fruit-body formation ofMycena chlorophos were studied. The optimum temperature of the mycelial growth was 27°C and the optimum initial pH of medium was 4.0. Peptone agar medium was suitable for the spawn culture. Compost medium containing rice bran at 10% (fw/fw) was appropriate for fruitbody formation in the Petri dish. Light was essential for initiation of primordia, and low-temperature treatment induced fruit-body formation effectively. The optimum conditions for fruit-body formation were found to be the cultivation at 27°C for 4 wk and continued cultivation for 3 wk under illumination at an intensity above 0.2 lx and at 21°C after casing with moist compost powder. In the fruit-bodies obtained, the maximum photosensitive wavelength of luminescence was 522 nm and the optimum temperature for emission was 27°C. The luminescence of a fruit-body was observed for about 3 d consecutively at 21°C.     

Responses of agaric fruit-bodies to light and gravity: growth straight downward in response to light from below

Fruit-bodies of Agaricales are known to show positive phototropism during the early stage of development, but negative gravitropism at the later stage after the onset of basidiospore formation. However, when exposed to light from below, the fruit-bodies ofTephrocybe tesquorum andCoprinus spp. grew downward through all stages of development, even after the onset of basidiospore formation. Primordium formation, fruit-body development and basidiospore formation were not disturbed under such conditions. In these downward-growing fruit-bodies, gills stood straight upward. InT. tesquorum, caps often became swollen and stipes sometimes became twisted anticlockwise, contrary to those in light from above, while such behaviours were not observed inCoprinus spp.     

Fruit-body production of a luminous mushroom,Mycena chlorophos

Cultural conditions for fruit-body production ofMycena chlorophos were investigated with the aim of using the mushroom for study of bioluminescence, scientific exhibition, and ecological conservation. A small glass jar having a cap with a microfilter was used as a culture vessel. A compost powder mixed with rice bran in proportion of 20% (fw/fw) and adjusted to 70% (w/w) in moisture content was used as production medium. Casing with 2 g/jar of moistened compost powder was necessary for fruit-body formation. Mycelium was grown in a culture chamber at 27°C, relative humidity (RH) of 80% for 4 wk, then transfered to a culture chamberat 21°C, 90% RH and light intensity of 300–800 lx after casing its, and incubated for 3 wk to produce fruit-bodies. The mean yield was 31 fruitbodies, i.e., 150 mg dry weight per jar.     

Metabolic function of glycogen phosphorylase and trehalose phosphorylase in fruit-body formation ofFlammulina velutipes

Glycogen phosphorylase in the vegetative mycelium ofFlammulina velutipes converts glycogen to α-glucose 1-phosphate (G1P) in the colony during fruit-body development. Glycogen may contribute to the synthesis of trehalose as the starting material in the vegetative mycelium during the fruiting process of the colony, and the trehalose produced is translocated into the fruit-bodies as the main carbohydrate substrate for their development. Trehalose phosphorylase activity in the vegetative mycelium was at a relatively high level until fruit-body initiation, suggesting the turnover of this disaccharide during the vegetative stage of the colony development. Trehalose phosphorylase activity in the stipes showed a peak level at the early phase of fruit-body development, suggesting the continuing phosphorolysis of trehalose by this enzyme. The stipes also showed a high specific activity of phosphoglucomutase at a sufficient level to facilitate the conversion of G1P to α-glucose 6-phosphate (G6P). In the pilei a large amount of G1P remained until the growth of the fruit-bodies ceased. Trehalase activities in the stipes and pilei were at a very low level, and this enzyme may not contribute to the catabolism of trehalose in the fruit-body development.     

Differential scanning calorimetric analysis of fruit-body and mycelium ofLentinula edodes

Differential scanning calorimetric (DSC) analysis was applied to the fruit-body (pileus and stipe) and mycelium, of shiitake mushroom (Lentinula edodes). Thermograms of each sample indicated distinctive patterns. However, chemical and infrared (IR) spectroscopic analyses showed that the compositions of pileus and stipe were similar to each other and different from that of mycelium. Because the DSC thermogram depends not only on chemical composition but also on physical properties such as density, the result of DSC analysis was assumed to indicate a difference in the state of cell wall between pileus and stipe.     

Effects of light on fruit-body formation in a basidiomycete, Coprinus macrorhizus

A basidiomycete, Coprinus macrorhizus produced only vegetativemycelia, when cultured under continuous darkness. Under continuouswhite light, visible tiny primordia formed on the 6th day afterinoculation, followed by normal development to fruit-bodies.Spores disseminated on the 11th day. However, when cultureswhere transferred to continuous darkness after the formationof primordia, rudimentary pilei with slender stalks formed.Abundant hairy hyphae were produced along the entire surfaceof the slender stalks. Thus, light was required-for both theinitiation and development of the fungal fruit-body. A fairy ring of primordia formed along the narrow region ofmycelia formed just prior to the exposure to light, provideda colony was pre-grown for more than 4 days in the dark, thenexposed to light for 24 hr or longer. Exposure to light for at least 48 hr during the period between24th and 96th hr after primordium initiation was required fornormal maturation of the fruit-body. This 48 hr light periodneeded for maturation of the fruit-body could be substitutedby two, 2 hr light periods given at the beginning and the endof the 48 hr period. We have tentatively concluded that lightis required at two definite stages for fruit-body developmentafter formation of the primordium. Effective wavelengths for both the initiation and developmentof fruit-bodies were in the near ultraviolet and blue regions. (Received July 24, 1972; )     

Growth of fruit-bodies inFavolus arcularius

The fruiting ofFavolus arcularius in culture is described. When the cultures, which have been pre-incubated in darkness to allow the inoculum mycelia to become thick and white wooly in texture, are exposed to light, fruit-body primordia, 1 mm in height, are formed about 4 days after the start of illumination. The primordium develops into a cylindrical stipe, the growth of which mainly occurs in the final 1 mm of the terminal region. Hyphal elongation in the region within 3 mm of the apex is predominant in the growth of the pileate stipe. With maturation of the stipe, changes in hyphal orientation occur on the periphery of the subapical region, and then the pileus-primordium is formed. The differentiation into the inner layer and the outer layer (pre-hymenial layer) in the pileus tissue is completed at this stage. The early growth of the pileus may be due to rapid elongation of the hyphae on the margin in addition to gradual expansion of the hyphae in the preformed pseudo-tissue. When the pileus has grown to about 3 mm in diameter, the subsequent three to four fold increase in size may be due to parallel expansion of the hyphae constituting the young pileus tissue.     

Characterization of proteins expressed abundantly in the fruit-body ofFlammulina velutipes

Chronological changes of protein expression in the vegetative mycelium ofFlammulina velutipes and expression of these proteins in the fruit-body were investigated by two-dimensional polyacrylamide gel electrophoresis. Four proteins (FBA 1-4) expressed abundantly in the fruit-body were found to have different expression patterns in the vegetative mycelium after the fruiting treatment. FBA 1-4 had similar amino acid sequences and displayed a high similarity with the deduced amino acid sequence of theC1 cDNA, which has an Arg-Gly-Asp (RGD) cell-attachment sequence. This suggests that FBA 1-4 may have cell-to-cell attachment activity.     

Isolation and characterization of developmental variants in fruiting using a homokaryotic fruiting strain ofCoprinus cinereus

Developmental variants in fruiting ofCoprinus cinereus were induced by mutagenizing oidia of the homokaryotic fruiting strain CopD5-12 with UV light. Through screening of 2,696 isolates, 1,018 strains exhibited defects in fruiting and were classified into 8 groups: (1) knotless variants, which fail to form hyphal knots, the first visible sign of fruiting; (2) primordiumless variants, which form hyphal knots but fail to develop fruit-body primordia; (3) maturationless variants, which form fruit-body primordia but do not form mature fruit bodies; (4) elongationless variants, which form mature fruit bodies with short stipes; (5) expansionless variants, which form mature fruit bodies with unexpanded pilei; (6) sporeless variants, which fail to produce black basidiospores, resulting in fruit bodies with white pilei after maturation; (7) compound type, which includes variants exhibiting several of the phenotypes described above; (8) others, including variants that produce a “dark stipe” even under in light/dark conditions, which is formed under continuous darkness in the wild-type. Two elongationless variants were characterized histologically.     

Sequential production of enzymes and basidiospore formation in fruiting bodies of Coprinus macrorhizus

The production of NADP-dependent glutamate dehydrogenase was initiated at the stage of first meiotic prophase in pileus cells but not in stipe cells of dikaryotic and monokaryotic fruiting bodies in Coprinus macrorhizus. The production of chitinase and glucanases assayed with laminarin and lichenan was observed after the completion of meiosis only in pileus cells. The light conditions that were effective for the delay or inhibition of cellular events in the pileus cells were also effective for the delay or inhibition of enzyme production. But all sporeless mutants tested, which were defective at the various stages of basidiospore formation, produced the normal levels of these enzymes. The results indicate that the sequential production of enzymes and cellular events leading to basidiospore formation in pileus cells are independent from each other.Abbreviation GDH_NADP NADP-dependent glutamate dehydrogenase     

Relationship between cumulative heat units and fruit-body emergence of ectomycorrhizal fungusTricholoma bakamatsutake in the fields

The relationship between cumulative heat units and fruit-body emergence ofTricholoma bakamatsutake was examined by using the method used for estimating dates of adult emergence of insects. Fruit-body numbers at a study site at Tateyama, Chiba Prefecture and records at a weather station near the site from 1987 to 1993 were used. For the seven years, daily average temperatures above the developmental threshold were cumulated for the days following induction of fruit-body development. The developmental threshold was taken to be 0°C, and the day when the daily minimum temperature fell to near 20°C in each year was taken as the day of induction of fruit-body development. A linear relationship between fruit-body numbers and daily average temperatures was observed as follows: Y=0.00376X + 1.873 (r=0.810), where Y is the probit of percentage of cumulative fruit-bodies, and X is the heat units above 0°C cumulated for the days following induction of fruit-body development. X for Y=5, which represents the cumulative emergence of 50% of fruit-bodies, was estimated to be 832 day-degrees.     

Effect of light on the initiation of pileus formation in a basidiomycete, Favolus arcularius

Pileus formation in Favolus arcularius is induced by light,but no photoinduction occurred in young epileate stipes. Thestipes usually had to attain a length of about 5 mm to be photosensitive.Synchronous pileus formation could be induced by exposure tolight using epileate stipes which had been preincubated in darknessfor 48 to 72 hr. The pileus primordium formed about 24 hr afterthe start of illumination, however, continuous illuminationwas not necessary to produce this effect. A dark period givenbetween 1 and 8 hr after the start of illumination did not retardpileus formation. The photoinduction of pileus formation involvedtwo light-requiring processes, one occurring during the firsthour (the first light process) and the other from the 8th tothe 24th hr (the second light process). The photoresponse inthe first light process was saturated with 5 lux of light, buta light intensity below 1 lux was essentially ineffective. Onthe other hand, the reaction in the second light process couldbe started by less than 2 lux, and was accelerated by increasingthe light intensities up to about 150 lux. Further increasesin light intensity did not improve any significant effect. (Received April 30, 1974; )     

Polyol metabolism in the mycelium and fruit-bodies during development ofFlammulina velutipes

Changes of polyol contents in the mycelium and fruit-bodies ofFlammulina velutipes were measured. The results suggested that arabinitol is accumulated in the fruit-bodies as the end-product after its translocation from the mycelium, while mannitol in the fruit-bodies is converted into fructose by the action of mannitol dehydrogenase (MDH). The development of fruit-bodies was promoted by feeding of mannitol to the mycelial colony. A¹⁴C tracer experiment indicated that half of mannitol translocated from mycelium to fruit-bodies was utilized for fruit-body development. NAD-linked MDH andd-arabinitol dehydroganase (D-ADH) were detected in both mycelium and fruit-bodies. The activities of MDH and ADH in the mycelium reached their maximum levels in the inital stage of fruit-body development and decreased thereafter. In contrast, the activity of MDH in the fruit-bodies showed a peak in the middle stage of development. The activity of ADH in the fruit-bodies was less than half of that of MDH. MDH showed a lower Km value for mannitol (1.3 ×10⁻³M) than for fructose (6.0×10⁻² M). The Km value of ADH for arabinitol was extremely high (1.3×10⁻¹M).     

枝顶孢霉对毒光盖伞子实体形成的影响

报道枝顶孢霉Acremonium strictum对毒光盖伞Psilocybe venenata子实体形成的影响。拮抗试验结果表明它们之间存在着较弱的干扰竞争作用;人工培养时,毒光盖伞混合菌株产生大型、小型和畸形3种类型的子实体,推测毒光盖伞畸形子实体的形成可能是枝顶孢霉寄生的结果,为毒光盖伞的人工栽培和进一步合理利用、野生蕈菌的驯化提供了理论依据。     

Influence of light on the morphological changes that take place during the development of the <Emphasis Type="Italic">Flammulina velutipes</Emphasis> fruit body

We show that fruit bodies of Flammulina velutipes can be induced in complete darkness after a sharp temperature reduction (23° to 16°C). However, the fruit bodies that form in complete darkness have a long stipe with an undeveloped pileus on the top (pinhead fruit bodies) and are thinner and whiter than the normal fruit bodies which are formed in the light. This finding suggests that F. velutipes fruit bodies cannot mature in complete darkness. However, when we irradiated the fruit bodies that had formed in complete darkness, a pileus developed immediately, and 4 days later the separation between the stipe and the pileus could be observed. Immediately after light exposure, the stipe also thickened and became increasingly pigmented. The stipe elongation was inhibited until 8 days after light exposure, although stipe elongation progressed very quickly thereafter. Basidospores were also visible in the gills 8 days after light exposure. We consider that the basidiospore development is involved in this rapid stipe elongation, which aids the effective dispersal of basidiospores.     

Effects of concentrated carbon dioxide on the fruiting of several cultivated basidiomycetes (II)

Edible basidiomycetesFlammulia velutipes andPleurotus ostreatus were cultivated in the usual manner on media based on sawdust and rice bran, and the cultures were exposed to slowly flowing CO₂-enriched air (550 (control), 3,000, 6,000, and 9,000µl/l) for seven days at different stages of cultivation. When the cultures were exposed at the primordium stage (less than 10 mm in length), length and yield of fruit-bodies increased and pileus expansion was slightly inhibited inF. velutipes, while inP. ostreatus length increased, yield decreased, and pileus expansion was greatly inhibited. When the cultures with fruit-bodies larger than 10 mm were exposed, length and yield were insensitive and pileus expansion was greatly inhibited inF. velutipes, while inP. ostreatus length was insensitive, but pileus expansion was heavily damaged by trumpet-like deformation and yield decreased. The different action of CO₂ on the two species appeared to be due to the different anatomical structures of their fruit-bodies.     

Hyphal ultrastructure in fruit-body primordia of the basidiomycetesSchizophyllum commune andCoprinus cinereus

Summary Light and electron microscopic investigations of fruit-body primordia of the basidiomycetesSchizophyllum commune andCoprinus cinereus showed that hyphal fusions are common in specific areas of the fruit-body primordia of both species. In these areas conspicuous amounts of a mucilaginous substance occur between the closely packed hyphae. A possible function of this mucilage is to aid the adhesion of hyphae prior to fusion. In the fruit-body primordium ofCoprinus cinereus the dolipore/parenthesome septum is surrounded by an additional hemispherical membranous cap (outer cap). Such a cap was never found inSchizophyllum commune fruit-body primordia.     

EXPERIMENTAL CONTROL OF FRUIT-BODY FORMATION IN COPRINUS MACRORHIZUS

In order to establish a proper experimental system for studying the physiological and biochemical processes of fruit-body formation in a Basidiomycetes, Coprinus macrorhizus Rea f. microsporus Hongo, various culture conditions, especially light and temperature, were investigated. The use of homogenates of fruit-body primordia, instead of mycelia, as inocula was effective for maintaining cultures capable of active fruit-body formation during many successive cultivations. At least two successive intermittent illuminations every 12 hr during the 3rd and 4th days of incubation were required for the differentiation of pilei. The most effective wave lengths of incident light were found in the region from 440 to 485 mμ. Temperature effects on fruit-body formation were exhibited in two stages of morphogenesis; i.e., in the induction of primordia formation from vegetative hyphae (by 5°-treatment) and in the transition phase from primordia formation to fruit-body development (by 20°-treatment). Based on these observations, three experimental systems for physiological and biochemical studies on the fruit-body formation have been proposed.     

Production of fruit-bodies of a mycorrhizal fungus,Lyophyllum shimeji,in pure culture

Cultivation of mycorrhizal fungus,Lyophyllum shimeji, was examined using selected strains capable of forming primordia in pure culture. Mycelia grew fastest on barley grains containing synthetic liquid medium. The primordia readily formed in test-tubes after lowering the incubation temperature from 23°C to 15°C. The co-existence of pine seedlings had no promotive effect on primordium formation. Fruit-bodies formed on a medium consisting of barley, beech sawdust, and liquid synthetic nutrients in 500-ml glass bottles. Mature fruit-bodies produced basidiospores. The spores thus produced could germinate on an agar medium and formed mycelial colonies. Thereby, the life cycle inL. shimeji was accomplished in pure culture without using the host plant.