新疆巴音布鲁克草原白蘑蘑菇圈土壤真菌多样性分析

【背景】新疆巴音布鲁克草原为我国第二大高山草原,草原上生长的白蘑(Tricholoma mongolicum Imai)属于口蘑属(Tricholoma)的一种,可形成典型的蘑菇圈。【目的】了解巴音布鲁克草原白蘑蘑菇圈圈上及其两侧土壤真菌的物种组成和群落结构特点,为研究白蘑蘑菇圈的形成与生长及其子实体的发生提供一定的理论依据。【方法】采用Illumina HiSeq平台高通量测序技术研究白蘑蘑菇圈周围土壤真菌的物种组成丰富度和菌群结构多样性。【结果】测定有效序列经注释得到809个操作分类单元(Optical taxonomic unit,OTU),分为5个门、26个纲、79个目、166个科、232个属;蘑菇圈上土壤真菌的物种丰富度、群落结构多样性以及特异性物种均低于圈外及圈内,蘑菇圈上特有真菌物种为Xylodonnothofagi、Agaricales、Phaeococcomyces、Ochrocladosporium adansoniae、Coniochaeta ligniaria、未知子囊菌、 Tomentella amyloapiculata、 Dothideomycetes、Incertea_sedis_Helotiales。【结论】研究表明白蘑蘑菇圈的形成影响土壤真菌的分布,圈上优势真菌类群对其他真菌类群具有抑制作用,蘑菇圈向外生长可能与微生物群落结构失衡有关。     

Oyster mushroom cultivation with rice and wheat straw

Cultivation of the oyster mushroom, Pleurotus sajor-caju, on rice and wheat straw without nutrient supplementation was investigated. The effects of straw size reduction method and particle size, spawn inoculation level, and type of substrate (rice straw versus wheat straw) on mushroom yield, biological efficiency, bioconversion efficiency, and substrate degradation were determined. Two size reduction methods, grinding and chopping, were compared. The ground straw yielded higher mushroom growth rate and yield than the chopped straw. The growth cycles of mushrooms with the ground substrate were five days shorter than with the chopped straw for a similar particle size. However, it was found that when the straw was ground into particles that were too small, the mushroom yield decreased. With the three spawn levels tested (12%, 16% and 18%), the 12% level resulted in significantly lower mushroom yield than the other two levels. Comparing rice straw with wheat straw, rice straw yielded about 10% more mushrooms than wheat straw under the same cultivation conditions. The dry matter loss of the substrate after mushroom growth varied from 30.1% to 44.3%. The straw fiber remaining after fungal utilization was not as degradable as the original straw fiber, indicating that the fungal fermentation did not improve the feed value of the straw.     

Effect of age,behaviour and social environment on honey bee brain plasticity

We examined the effects of behaviour, age and social environment on mushroom body volume in adult bees. The mushroom bodies are regions of the central brain important for sensory integration and learning. Their volume was influenced by behaviour throughout life: always larger in forager bees than age-matched nurse bees, even in old bees up to 93 days of age as adults. Mushroom body development was influenced by the social environment in the first 8 days of adult life, with different environments having markedly different effects on mushroom body size. Compared to hive-reared bees, isolation slowed mushroom body growth, but bees reared in isolation confined with a single dead bee showed a dramatic increase in mushroom body volume comparable to that seen in active foragers. Despite their precocious mushroom body development, these bees did not show improved performance in an olfactory learning test. Since simple environmental manipulations can both accelerate and delay mushroom body growth in young bees, and since mushroom body volume is sensitive to behaviour throughout life, the honey bee has great potential as a model for exploring the interactions between environment, behaviour and brain structure.     

Effects of cultural conditions on the mycelial growth of healthy and virus-infected cultivated mushroom, Agaricus bisporus

There was a significant inverse correlation (P= 0=001) between concentrations of mushroom viruses 1 and 2 in sporophores and amounts of mycelial growth on malt agar of isolates taken from them. Increasing virus concentrations decreased linear growth of one mushroom strain from 76 mm (healthy) to 35 mm (mildly infected) and 7 mm (severely infected) when incubated at 25°C for 3 wk. Mycelial growth rates of isolates from healthy and from virus-infected mushrooms were compared on eleven agar media. All media clearly differentiated between healthy and severely infected isolates, but fewer separated healthy from mildly infected isolates. Those that did contained maltose, sucrose or starch as carbon source. Media containing peptone usually gave better differentiation than those with other sources of nitrogen, but the best differentiation was obtained with malt agar. Growing healthy and infected isolates on a range of media affected their subsequent growth on malt agar, the growth of some isolates apparently being changed permanently after 2 months on some of the different media. Whereas none of the infected isolates grew less rapidly after this treatment, the growth of some of the mildly infected isolates improved to such an extent that they could no longer be distinguished from healthy isolates. After heat-treatment (1–6 wk at 33°C), mycelial growth rates of infected isolates were increased, but viruses 1 and 2 were not always eliminated unless the heat-treatment was begun immediately after subculture. Mycelial growth rate and colony characters are not infallible criteria of the presence or absence of virus, a feature of particular significance when checking the health of mushroom spawn.     

Experiments to determine the effect of certain wood preservatives on the growth and cropping of the cultivated mushroom (Psalliota campestris)

A small-scale laboratory method of determining the effect of wood preservatives on growth and cropping of the cultivated mushroom is outlined. Experiments with a number of well-known wood preservatives are described. According to these experiments wood treated with the following preservatives had no adverse effect on mycelial growth or on croppings: 5 % copper sulphate solution, green Cuprinol, 5 % Celcure solution, 2 % Triolith (Wolman salts) solution. On the other hand, wood treated with 2 % Chromel salt and coal-tar creosote reduced the vigour of growth of mushroom mycelium to a depth of 1/2 in. in compost that was in contact with it. Under these conditions, however, the mycelium was not killed nor was the cropping reduced even when the treated wood was only 1 1/2 in in. below the casing soil. As in all experiments the treated wood was covered with compost, the chance of vapours from the preservatives coming into contact with sporophores was very small, and the possibility of harmful effect in mushroom houses from such vapours should not be ignored.
The experiments indicate that full-scale trials in commercial mushroom houses could be undertaken with copper sulphate, green Cuprinol, Celcure and Triolith with negligible risk to the crop, but that it is advisable to carry out trials on a smaller scale with Chromel and coal-tar creosote of known composition to determine whether these preservatives have any adverse effect on cropping. Owing to the great range in composition shown by coal-tar creosote it is most important that the conclusions reached with the particular sample used in the above experiments should not be applied to creosotes in general.     

Role of Bacillus spp. in antagonism between Pleurotus ostreatus and Trichoderma harzianum in heat-treated wheat-straw substrates

This study aimed to identify bacteria involved in Trichodermaharzianum inhibition while promoting Pleurotus ostreatus defences in order to favour cultivation-substrate selectivity for mushroom production. PCR-DGGE profiles of total DNA from wheat-straw substrate showed weak differences between bacterial communities from substrate inoculated with P. ostreatus with or without T. harzianum. The major cultivable bacteria were isolated from three batches of wheat-straw-based cultivation substrates showing an efficient selectivity. They were screened for their ability to inhibit T.harzianum. By using specific media for bacterial isolation and by sequencing certain 16S-rDNA, we observed that Bacillus spp. were the main inhibitors. Among them, a dominant species was identified as Paenibacillus polymyxa. This species was co-cultivated on agar media with P. ostreatus. The measurement of laccase activities from culture plugs indicated that P. polymyxa induced increases in enzyme activities. Bacillus spp. and specifically P. polymyxa from cultivation substrates are implicated in their selectivity by both inhibiting the growth of T.harzianum and stimulating defences of the mushroom P. ostreatus through the induction of laccases. The management of microbial communities during P.ostreatus cultivation-substrate preparation in order to favour P. polymyxa and other Bacillus spp. growth, can be a way to optimize the development of P. ostreatus for mushroom production or other environmental uses of this fungus.     

Effect of environmental factors on the yield of selected mushroom species growing in two different agro ecological zones of Pakistan

Mushrooms are a rich source of protein and vitamins as human food. In view of the growing importance of mushroom in Pakistan, a research study was initiated with the objective to examine the suitability of Oyster mushroom cultivation and to compare the growth and yield of Oyster mushroom in two different areas (Peshawar and Swat, North-West region of Pakistan) with different ecological conditions. Spawn running time, number of crops, stalk height, stalk diameter, cap size, fresh weight, number of production days, and the interval in days between the time of bag opening and the time of starting fruiting bodies formation were among the important parameters investigated in the current study. Stalk height, stalk diameter, cap size and fresh weight of mushrooms were found higher in Peshawar region as compared to those growing in Swat region. On the other side, the spawn running time, formation of fruiting bodies and the number of productions were higher in Swat region as compared to the mushroom under study in Peshawar region. Mild winter temperatures of Peshawar region, and low summer temperatures in Swat, were found most suitable for growth and yield of Pleurotus ostreatus.     

A distinctive ribonuclease from fresh fruiting bodies of the medicinal mushroom Ganoderma lucidum

A ribonuclease with an N-terminal sequence distinct from other mushroom ribonucleases was isolated from fresh fruiting bodies of the medicinal mushroom Ganoderma lucidum. The ribonuclease was adsorbed on DEAE-cellulose and Q-Sepharose, and unadsorbed on CM-Sepharose. It possessed a molecular mass of 42 kDa as judged by gel filtration by fast protein liquid chromatography on Superdex 75 and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Its molecular mass was similar to that of straw mushroom ribonuclease but much higher compared with those of other mushroom ribonucleases. The ribonuclease was unique among mushroom ribonucleases in that it exhibited the highest potency toward poly(U), followed by poly(A). Its activity toward poly(G) and poly(C) was about one-half of that toward poly(A) and one-quarter of that toward poly(U). A pH of 4.0 and a temperature of 60 degrees C were required for optimal activity of the enzyme. The optimum pH was low compared with those reported for other mushroom ribonucleases.     

The General Secretory Pathway of Burkholderia gladioli pv. agaricicola BG164R Is Necessary for Cavity Disease in White Button Mushrooms

Cavity disease in white button mushrooms is caused by Burkholderia gladioli pv. agaricicola. We describe the isolation and characterization of six mutants of the strain BG164R that no longer cause this disease on mushrooms. The mutations were mapped to genes of the general secretory pathway (GSP). This is the first report of the association of the type II secretion pathway with a disease in mushrooms. Phenotypes of the six avirulent mutants were the following: an inability to degrade mushroom tissue, a highly reduced capacity to secrete chitinase and protease, and a reduced number of flagella. Using these mutants, we also made the novel observation that the factors causing mushroom tissue degradation, thereby leading to the expression of cavity disease, can be separated from mycelium inhibition because avirulent mutants continued to inhibit the growth of actively growing mushroom mycelia. The GSP locus of B. gladioli was subsequently cloned and mapped and compared to the same locus in closely related species, establishing that the genetic organization of the gsp operon of B. gladioli pv. agaricicola is consistent with that of other species of the genus. We also identify the most common indigenous bacterial population present in the mushroom fruit bodies from a New Zealand farm, one of which, Ewingella americana, was found to be an apparent antagonist of B. gladioli pv. agaricicola. While other investigators have reported enhanced disease symptoms due to interactions between endogenous and disease-causing bacteria in other mushroom diseases, to the best of our knowledge this is the first report of an antagonistic effect.     

A Note on a Selective Isolation Medium for the Thermophilic Actinomycete Thermomonospora chromogena

Thermomonospora chromogena was isolated from mushroom compost by spreading diluted suspensions on an agar medium containing kanamycin at 25 µg/ml. The antibiotic prevented the growth of other thermophilic actinomycetes on media incubated at 50°C and significantly reduced the growth of associated bacteria.     

Effect of lignin-derived phenolic monomers on the growth of the edible mushrooms Lentinus edodes,Pleurotus sajor-caju and Volvariella volvacea

Pleurotus sajor-caju was generally more tolerant to lignin-related phenolic monomers and tannin derivatives than Lentinus edodes and the straw mushroom, Volvariella volvacea. Several phenols, at up to 5 mM, enhanced mycelial growth of P. sajor-caju. No clear pattern was evident when the effects of phenols and tannins on the growth of V. volvacea and L. edodes were compared, but the lower concentrations of 4-hydroxybenzaldehyde and vanillin which were tested were markedly more toxic to the straw mushroom. The distribution of phenolic monomers and tannin derivatives in the agricultural wastes used for mushroom cultivation may be an important growth determinant. However, the differences in the growth inhibition profiles of L. edodes, P. sajor-caju and V. volvacea suggest that, alone, the effect of these compounds on fungal growth is unlikely to account for the varying abilities of the three mushroom species to grow and fruit on a particular lignocellulosic substrate.     

Bioconversion and biotransformation of coir pith for economic production of Pleurotus florida: chemical and biochemical changes in coir pith during the mushroom growth and fructification

Coir pith represents ∼50% of the waste from the coir industries and was tested for its potential in serving as a growth substrate for the production of species of oyster mushroom, Pleurotus florida. Due to its high lignin (∼48%) content and amorphous powdery nature, coir pith supported poor mushroom mycelial growth and yields were considerably low (∼25% bioconversion efficiency). Pre-treating coir pith with hot water did not prove economical to produce the mushroom yields. Acid swelling and alkali delignification of coir pith though served to change the structure of coir pith; the mushroom yields were not improved. Amendment of coir pith with rice (Oryza sativa) straw and horse gram (Dolichos biflorus) plant residue tended to greatly modify the physical characteristics of the inoculated mushroom bed. Such a supplementation of coir pith growth substrate resulted in production of mushroom yields with 110–125% bioconversion efficiency. Implications of supplementing coir pith with rice straw/horse gram plant residue in terms of holocellulose:lignin ratio are discussed. Sensorially, the mushrooms so produced did not differ from that on rice straw, the economic growth substrate recommended for production of the mushroom yields on commercial scale. Changes in cellulose, hemicellulose and lignin contents of coir pith amended with rice straw were studied. Cellulase, hemicellulase and protease enzyme activities in the amended coir pith substrate showed a continuous increase from inoculation till the end of fructification, whereas laccase activity decreased during fructification, in consonance with decreased lignin degradation during fructification.     

The microbial population in the air of cultivation facility of oyster mushrooms

The microbial population in the air of mushroom cultivation facility was studied to understand the population structure and size depending on the cultivation methods and regions. The air contents of ten farmers’ oyster mushroom cultivation facilities in Kyunggi province were sampled. The results indicated that there was no difference in population size depending on the regions of mushroom cultivation. In addition, the population size of bacteria in the growth room was bigger than that of the cooling room and outside of the mushroom house, but the fungal population was similar in size between cultivation stages. With regard to population structure, Pseudomonas and Penicillium species were most frequently isolated from the air of oyster mushroom cultivation facility.     

Effect of spent mushroom compost tea on mycelial growth and yield of button mushroom (Agaricus bisporus)

Preliminary studies suggested that the use of compost tea made from spent mushroom substrate (SMS) may be regarded as a potential method for biologically controlling dry bubble disease in button mushroom. The aim of this study was to assess the effect of SMS compost tea on the host, the button mushroom, to ascertain whether the addition of these water extracts has a toxic effect on Agaricus bisporus mycelium growth and on mushroom yield. In vitro experiments showed that the addition of SMS compost tea to the culture medium inoculated with a mushroom spawn grain did not have an inhibitory effect on A. bisporus mycelial growth. The effect of compost teas on the quantitative production parameters of A. bisporus (yield, unitary weight, biological efficiency and earliness) was tested in a cropping trial, applying the compost teas to the casing in three different drench applications. Quantitative production parameters were not significantly affected by the compost tea treatments although there was a slight delay of 0.8-1.4 days in the harvest time of the first flush. These results suggest that compost teas have no fungitoxic effect on A. bisporus so that they can be considered a suitable biocontrol substance for the control of dry bubble disease.     

Beneficial interactions between bacteria and edible mushrooms

Mushroom-forming fungi establish mutual beneficial interactions with plants and degrade organic waste. These fungi also play an important role in human societies to produce mycelium materials, as a source of medicinal compounds, and as food. Bacteria interact with mushroom-forming fungi not only as competitors for nutrients and as pathogens but also to establish beneficial interactions. This review discusses the positive interactions of bacteria during the different stages of the life cycle of the white button mushroom Agaricus bisporus and other highly consumed mushroom-forming fungi. Bacteria are key in forming a selective substrate, in providing nutrients, in stimulating growth and mushroom formation, and in protection against pathogens. Implications for the mushroom industry are being discussed.     

Properties of peat-based casing soils and their influence on the water relations and growth of the mushroom (Agaricus bisporus)

Different combinations of peat and chalk or lime sources with differing moisture contents were used to determine how specific physical and chemical properties of the casing soil relate to the growth and water relations of the mushroom. The peat types varied in terms of decomposition and extraction method; the lime addition varied in terms of rate and type (chalk or sugar beet lime). During the colonisation of the casing soil before fruiting, the extension growth rate of mushroom mycelium was most closely correlated (negatively) with the volumetric moisture content of the casing soil. Scanning electron microscopy showed that mycelium growing at a lower casing soil matric potential (Ψ_m) had a much finer and branched structure than mycelium growing at a higher Ψ_m. Across all the peat and lime source treatments, a relationship was found between the mean Ψ_m of the casing soil and mushroom yield, with an optimum Ψ_m of -7.9 to -9.4 kPa. Mushrooms are produced in ‘flushes’ at about 8-day intervals and during the development of each flush of mushrooms, there was a significant decrease in casing soil Ψ_m . This decrease (to below -40 kPa) was greatest in the second flush, which was the highest yielding. There were no relationships between mushroom yield and casing soil osmotic potential Ψ_π within the range -93 to -154 kPa or any of the other chemical properties and water and air holding characteristics of the casing soils which were determined. Across different casing soil treatments, mushroom dry matter content was negatively correlated with mushroom yield and positively correlated with mushroom tissue osmotic potential. This revised version was published online in June 2006 with corrections to the Cover Date.     

Effect of Pseudomonas sp. P7014 on the growth of edible mushroom Pleurotus eryngii in bottle culture for commercial production

Addition of bacterial culture strain P7014 and its supernatant to the mushroom growing media resulted in mushroom mycelia run faster. Mycelial growth rate of Pleurotus eryngii was increased up to 1.6 fold and primordial formation was induced one day earlier. Moreover, it was supposed that addition of bacteria had beneficial applications for commercial mushroom production, which appreciably reduced total number of days for cultivation of about 5+/-2 days compared with uninoculated, which took 55+/-2 days.     

Pseudomonas tolaasii on mushroom (Agaricus bisporus) crops: bactericidal effects of six disinfectants and their toxicity to mushrooms

N -Cetylpyridinium chloride, benzalkonium chloride, Cetrimide, bronopol (2-bromo-2-nitropropane-1,3-diol), Panacide and Chloramine T were tested as possible disinfectants for use in growing mushrooms (Agaricus bisporus) where Pseudomonas tolaasii blotch is prevalent. The most effective materials in vitro against Ps. tolaasii where the quaternary ammonium compounds and bronopol in terms of the MIC and MCC tests. In 8 min 'clean' and 'dirty' tests incorporating yeast cells bronopol did not kill the pathogen, whereas the other five disinfectants did so. If mushroom casing (peat plus limestone) was added to these short duration tests the pathogen survived all six disinfectants. When tests with added casing were extended to 20 h, bronopol was very effective (cidal value 100 µg/ml) and the pathogen was not killed by the other five disinfectants. In experiments on agar plates, bronopol and chloramine T were stimulating to the growth of A. bisporus. Growing mushroom caps treated with bronopol remained white, whereas caps treated with the other five disinfectants turned brown within 30 min. It is thus likely that bronopol could be used to control the source of bacterial blotch epidemics in mushroom growing, which previous work has shown to be in the casing.     

Effects of Entomopathogenic Nematodes on Control of a Mushroom-infesting Sciarid Fly and on Mushroom Production

The entomopathogenic nematodes Steinernema feltiae (Biosys strain #27) and Heterorhabditis heliothidis were evaluated for the larval control of a mushroom-infesting sciarid, Lycoriella mali, and for the effects of these nematodes on mushroom (Agaricus bisporus) production. In a series of small-scale mushroom crops, infective-stage H. heliothidis and S. feltiae were applied to the mushroom casing surface in the irrigation water or incorporated into the casing material at densities ranging from 28 to 1120 and 11 to 1120 nematodes cm-2 of casing surface respectively. The mortality of L. mali larvae ranged from 52 to 100% for H. heliothidis and 38 to 100% for S. feltiae. Both nematode species reduced mycelial coverage on the casing surface at primordia initiation. Neither mushroom strain (off-white or white hybrid) or method of application (incorporation into or irrigation onto the casing surface) altered the effect on mycelial coverage. The nematodes's negative effect on mycelial growth confounded the benefit of fly control. At high nematode densities (up to 1120 nematodes cm-2), damage-free mushroom yields for the first week of harvest were less than those from the untreated control. However, at lower nematode densities, at or below 140 cm-2, the nematodes had less effect on mushroom growth, and consequently, damage-free mushroom yields for the first week of harvest were frequently greater than those from the untreated control. In the absence of flies, the first-week mushroom yield generally declined with increasing nematode densities for both white and off-white mushroom hybrids. After 4 weeks of harvest, accumulated mushroom yields had nearly recovered from the earlier decline.     

Diversity and spacio‐temporal distribution of mushrooms in a Nigerian savanna: implication for their conservation

We surveyed the macrofungi of an area dominated by northern Guinea savanna habitats in north‐east Nigeria. A total of 93 different species of mushrooms were found in the study area. These species belong to 29 different families, most species belonging to the family Agaricaceae, Lyophyllaceae, Bolbitiaceae, Pluteaceae and Polyporaceae. A total of 48 species belonged to the Agaricaceae, followed by Lyophyllaceae represented by 6 species. The micro‐habitats of mushrooms in the study area include wood, soil around dead tree stump, waste dump, cow dung, fallow, arable land, and 22 different living trees species. The most important habitats in term of mushroom species diversity were Parkia biglobosa, Tamarindus indica and dead wood. The Parkia biglobosa tree had the highest species richness (45) and species diversity (Shannon diversity index, SDI: 3.6). Tamarindus indica was the second, having 28 species richness and 2.7 SDI. These were followed by dead wood where 22 different mushroom species were recorded and has of 2.1 SDI. Also, these three habitats (Parkia biglobosa, dead wood and Tamarindus indica) had the highest number of mushroom species (14, 8 and 6 respectively) that were confined to them. Most of the other mushroom species were confined to only one microhabitat. There was no statistically significant difference in mushroom abundance between arable land and fallow. Collectively, the indigenous trees were associated by more mushroom species (63) than the exotic trees (20) and the indigenous trees also had significantly higher mushroom abundance than the exotic trees. However, the non‐indegenous trees had more species forming mycorrhiza than the indegenous trees, presumaby because the former were able to form symbioses with both native fungi and introduced species from their origina habitats. Inter‐annual variation of mushroom species diversity was also observed. Human activities contribute positively to mushroom diversity in the study area by creating some unique micro‐habitats that support the growth of certain unique mushroom species. Therefore, for maximum conservation of mushroom diversity, conservation measures excuding all human activities should be avoided.