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.     

食用菌与木霉菌互作机制研究进展

在食用菌生产中木霉菌不仅污染食用菌培养料,而且感染其菌丝体和子实体,常造成巨大的经济损失。本文综述了食用菌与木霉菌互作的形态学特征和生物化学基础,介绍了食用菌抗病性遗传及抗性机制研究现状,提出了未来宿主与病原菌互作机制研究的方向。     

食药用真菌: 天然抗氧化剂的重要来源

生物体在新陈代谢过程中不断产生自由基。自由基在机体内的生成和去除通常处于平衡状态,不会对机体造成严重损伤,但当机体内的自由基过剩时,常引起生物大分子如脂类、蛋白质和核酸的氧化损伤,进而引发机体衰老以及癌症、动脉粥样硬化、风湿性关节炎、肺气肿等疾病。过去20年中,自由基在细胞损     

Antagonism between bacteria and fungi: substrate competition and a possible tradeoff between fungal growth and tolerance towards bacteria

Bacteria and fungi often share a common substrate, and their spatial proximity in many environments has lead to either synergistic or antagonistic interactions. In this paper, the interaction of bacterial and fungal decomposers from an aquatic environment was studied. We found indications of a tradeoff between fungal growth and tolerance towards bacteria. Fungal strains growing best in absence of bacteria were most severely affected by bacterial presence, while those less suppressed during co-existence with bacteria had lower maximal growth rates in bacterial absence. Additionally, we show that the antagonism between bacteria and fungi is connected to competition for substrate, but that this competition can be drastically altered if fungi are given an opportunity to establish before inoculation of bacteria. Established fungi out-competed bacteria, and gained higher biomass than in simultaneously inoculated treatments with higher substrate concentrations.     

Cultivation of mushrooms of edible ectomycorrhizal fungi associated with Pinus densiflora by in vitro mycorrhizal synthesis

Edible mushroom fungi in the genera Lyophyllum, Tricholoma, Leucopaxillus, Suillus, Rhizopogon, Lactarius, and Morchella were tested for mycorrhization with Pinus densiflora in vitro. Most of the tested fungi in the genera Lyophyllum, Tricholoma, Suillus, Rhizopogon, and Lactarius formed ectomycorrhizas 2–4 months after fungal inoculation. Mycorrhizal seedlings were then acclimatized in open-pot soil under growth-chamber conditions. Almost all mycorrhizal seedlings sustained their symbiont and developed new mycorrhizas for 8–9 months after transplantation. Under these conditions, more than half of the tested species formed primordia and Tricholoma flavovirens, Rhizopogon rubescens, and Lactarius akahatsu developed basidiocarps with young host plants. Accepted: 28 November 2000     

Cultivation of mushrooms of edible ectomycorrhizal fungi associated with Pinus densiflora by in vitro mycorrhizal synthesis

The morphology and anatomy of ectomycorrhizas of edible mushroom fungi in association with Pinus densiflora seedlings are described. These include species of Lyophyllum, Tricholoma, Suillus, Rhizopogon, and Lactarius. Almost all mycorrhizas synthesized in vitro could be acclimatized in open-pot soil conditions after 8–9 months. Although mycorrhizal anatomy was almost identical under in vitro and open-pot culture conditions, external morphology, such as the development of rhizomorphs and hydrophobic aerial hyphae, differed between the two conditions in some fungal species. Fully developed, mature mycorrhizas of different fungal species could be distinguished as ectomycorrhizal morphotypes, which could also be distinguished by PCR-RFLP analysis of their rDNA.     

Antibiosis between ruminal bacteria and ruminal fungi

Cellulose digestion, bacterial numbers, and fungal numbers were monitored over time in vitro by using a purified cellulose medium with and without antibiotics (penicillin and streptomycin). All fermentations were inoculated with a 1:10 dilution of whole rumen contents (WRC). Without antibiotics, cellulose digestion was higher (P < 0.01) at 24, 30, 48, and 72 h; fungi had almost disappeared by 24 h, while bacterial concentrations increased over 100-fold in 24 h and then decreased gradually up to 72 h. In those fermentations with added antibiotics, fungal concentrations increased 4-fold by 30 h and up to 42-fold at 72 h; bacterial concentrations were markedly reduced by 24 h and remained low through 72 h. Similar results were obtained with ground alfalfa as a substrate. In further studies, the in vitro fermentation of purified cellulose without antibiotics was stopped after 18 to 20 h, and the microbial population was killed by autoclaving. Antibiotics were added to half of the tubes, and all tubes were reinoculated with WRC. After 72 h, extensive cellulose digestion had occurred in those tubes without antibiotics, as compared to very low cellulose digestion with added antibiotics. The extent of this inhibition was found to increase in proportion to the length of the initial fermentation period, suggesting the production of a heat-stable inhibitory factor or factors. The inhibitory activity was present in rumen fluid, could be extracted from lyophilized rumen fluid (LRF) with water, and was stable in response to proteolytic enzymes. In addition, the water-extracted residue of LRF was found to contain growth factor activity for rumen fungi in vitro.     

Compost bacteria and fungi that influence growth and development of Agaricus bisporus and other commercial mushrooms

Applied Microbiology and Biotechnology - Mushrooms are an important food crop for many millions of people worldwide. The most important edible mushroom is the button mushroom (Agaricus bisporus),...     

Cultivation of Pleurotus ostreatus and other edible mushrooms

Pleurotus ostreatus is the second most cultivated edible mushroom worldwide after Agaricus bisporus. It has economic and ecological values and medicinal properties. Mushroom culture has moved toward diversification with the production of other mushrooms. Edible mushrooms are able to colonize and degrade a large variety of lignocellulosic substrates and other wastes which are produced primarily through the activities of the agricultural, forest, and food-processing industries. Particularly, P. ostreatus requires a shorter growth time in comparison to other edible mushrooms. The substrate used for their cultivation does not require sterilization, only pasteurization, which is less expensive. Growing oyster mushrooms convert a high percentage of the substrate to fruiting bodies, increasing profitability. P. ostreatus demands few environmental controls, and their fruiting bodies are not often attacked by diseases and pests, and they can be cultivated in a simple and cheap way. All this makes P. ostreatus cultivation an excellent alternative for production of mushrooms when compared to other mushrooms.     

Behavioural response of the fungus gnat,Bradysia impatiens (Diptera: Sciaridae) towards certain edible mushrooms and saprophytic fungi

The fungus gnat Bradysia impatiens (Johannsen) is a worldwide pest inhabiting organic-rich environments, including mushroom-cultivation substrates, which leads to massive production losses of edible mushrooms. To promote a non-insecticidal pest control strategy, we evaluated adult behavioural response towards two saprophytic fungal strains Aspergillus flavus Link and Mucor circinelloides Tiegh., isolated from B. impatiens-inhabiting substrates and six edible mushrooms species. Our results indicated that (a) B. impatiens was most attracted to the oyster mushroom Pleurotus ostreatus among all six edible mushrooms; (b) males and females demonstrated a significant attraction for M. circinelloides over A. flavus and P. ostreatus; (c) adults demonstrated dynamic attraction tendencies that varied with the culture periods of A. flavus and M. circinelloides, wherein females represented most (mean = 78.6%) of the attracted individuals; and (d) larvae that fed on mycelial cultures of M. circinelloides could complete their entire life cycles, but larvae could not survive on a non-fungal or A. flavus diet. These results demonstrate the potential for the development of M. circinelloides in a push-pull strategy to biocontrol this pest in edible mushroom cultivation.     

食用菌科学研究为食用菌产业发展提供越来越重要的科学支撑

食用菌学科建设和食用菌产业发展密切关联,我国食用菌产业的蓬勃发展和转型升级中,产生了大量的科学问题和需求,这成为食用菌学科科学研究中最好的方向和主题,也是食用菌学科建设的重要动力源泉.《菌物学报》作为我国重要的菌物科学研究的期刊,每年刊登许多与食用菌学科相关的研究论文,今年再次集中出版一期食用菌遗传育种及生理生化主...     

Production of edible mushrooms in forests: trends in development of a mycosilviculture

Developing the production of ectomycorrhizal (ECM) mushrooms in forest has become a challenge. Only a few ECM species are currently cultivable. Controlled mycorrhization practices offer promising advance to produce currently uncultivable ECM mushrooms. The persistence of the production of edible species, either cultivated or wild, depends on both the tree and the ecological environment (fungal communities, climate, soil, tree development). Developing adapted forest management practices appears to be means to improve production of edible ECM mushrooms. This review summarises current knowledge on the development of a science-based mycosilviculture for the production of edible ECM mushrooms.     

Interactions between arbuscular mycorrhizal fungi and soil bacteria

The soil environment is interesting and complicated. There are so many interactions taking place in the soil, which determine the properties of soil as a medium for the growth and activities of plants and soil microorganisms. The soil fungi, arbuscular mycorrhiza (AM), are in mutual and beneficial symbiosis with most of the terrestrial plants. AM fungi are continuously interactive with a wide range of soil microorganisms including nonbacterial soil microorganisms, plant growth promoting rhizobacteria, mycorrhiza helper bacteria and deleterious bacteria. Their interactions can have important implications in agriculture. There are some interesting interactions between the AM fungi and soil bacteria including the binding of soil bacteria to the fungal spore, the injection of molecules by bacteria into the fungal spore, the production of volatiles by bacteria and the degradation of fungal cellular wall. Such mechanisms can affect the expression of genes in AM fungi and hence their performance and ecosystem productivity. Hence, consideration of such interactive behavior is of significance. In this review, some of the most important findings regarding the interactions between AM fungi and soil bacteria with some new insights for future research are presented.     

Pathogenicity of a fungus resembling Wangiella dermatitidis isolated from edible mushrooms

A fungus resembling the human pathogen Wangiella dermatitidis (Kano) McGinnis, a dematiaceous hyphomycete, was recovered from imported desiccated "black fungus" mushrooms (Auricularia polytrichia (Mont.) Sacc.), a food item popular in Far Eastern cuisine. Except for its conidia, which are mostly reniform to allantoid rather than ovoid as is characteristic for W. dermatitidis, and the undecided mode of conidiogenesis, the isolate closely resembles W. dermatitidis in gross and microscopic morphology, thermotolerance, and general and neurotrophic infectivity patterns in mice injected intraperitoneally. The foodborne isolate was also infective for infant mice inoculated by oral intubation. The systematic position of the isolate is still under investigation. There has been no previous report of W. dermatitidis or of a fungus resembling it occurring in or on foods or of the infectivity of a fungus for a mammalian host by oral intubation.     

重要食药用菌多糖降血糖分子机制研究进展

目前以糖尿病为代表的糖代谢紊乱疾病愈演愈烈,严重危害人体健康.食药用菌多糖因其具有良好的调节糖代谢作用而被关注,但其调节糖代谢的作用机制并未被很好地综述.本文从关键基因、蛋白、信号通路等方面综述了食药用菌活性多糖的降血糖机制,包括抑制蛋白酪氨酸磷酸酶1B(Protein Tyrosine Phosphatase-1B,...     

Interactions between fungi,bacteria and beech leaves in a stream microcosm

Summary Immigration and colonization of isolates of naturally occurring stream bacteria and hyphomycetes on beech leaves were studied in a laboratory stream microcosm. Fungal spores were more successful immigrants, especially on new leaves, than bacteria, which were more repelled than attracted by the substrate. Fewer bacteria immigrated to older leaves than to new, and bacteria multiplied faster in water than on leaves. Fungi and bacteria showed synergistic relationships so that each group grew significantly faster in presence of the other group. If one considers, differences in immigration, colonization and synergism patterns, fungal mycelia doubled about 10 times faster than bacterial cells which might explain the dominance of fungi usually found on leaves in early decay. The individual fungal species could be assigned to one of three colonization groups; one of fugitive species, preceding a second group of species that grew from rarity to dominance, and a third group of very slow colonizers. The leachate was fractionated in different molecular size classes by gel chromatography, and the fraction around 2500D in the new leaf leachate was associated with a high concentration of polyphenols. High-pressure liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) revealed the presence of 16 phenolic acids in the new leaf leachate at concentrations ranging from < 1 to 640 g l^–1. All fungi except the species with the slowest growth rate grew faster on leachate with the fraction around 2500D removed, and the density of bacteria was significantly reduced when pure stream water was supplemented with compounds from the same fraction.     

食用菌生物修复重金属污染研究进展

生物修复是利用生物体及其衍生物对重金属进行吸收/吸附来处理环境中重金属污染的方法,具有成本低、来源广、无二次污染等特点.食用菌富集重金属是生物修复的一个重要研究方向,食用菌修复作用主要通过对重金属的吸收来降低其生态毒性,从而对重金属污染起到一定的修复作用.本文论述了食用菌对重金属Cu、Cd、Pb、Zn、As、Cr的富集作用,揭示了食用菌富集重金属的可能机理,并对采用食用菌富集重金属以治理环境污染的前景进行了展望.