有害疣孢霉菌与双孢蘑菇的互作关系

通过菌丝对峙、双重培养,以及对发病双孢蘑菇子实体的显微观察,探讨有害疣孢霉菌Mycogone perniciosa（MP0012）与双孢蘑菇Agaricus bisporus（As2796）之间的互作关系。结果表明,在菌丝对峙生长阶段有害疣孢霉菌菌丝不侵入双孢蘑菇菌丝体内,两者可交叉生长,对双孢蘑菇生长影响不显著;对峙与双重培养均显示有害疣孢霉菌菌丝会产生对双孢蘑菇菌丝生长的抑制作用的挥发性物质,造成双孢蘑菇菌丝扭结断裂。同时试验证实了双孢蘑菇菌丝会促进有害疣孢霉菌厚垣孢子的产生和萌发、菌丝生长和发育。侵染实验结果表明,有害疣孢霉菌可直接侵染双孢蘑菇子实体,引起双孢蘑菇子实体病害;对罹病子实体显微观察结果发现,发病前期双孢蘑菇子实体表面长出绒毛状病原菌丝,菌柄中空,菌褶褐变腐烂并长出病原菌丝;发病中期双孢蘑菇子实体内菌丝组织会出现萎缩裂解现象,在近有害疣孢霉菌菌丝一侧的双孢蘑菇子实体菌丝细胞壁被降解;发病后期双孢蘑菇子实体菌丝组织基本消失。由此初步判断有害疣孢霉菌对双孢蘑菇的寄生类型偏向于死体营养型。     

福建省有害疣孢霉菌Mycogone perniciosa的种群分化初探

对16株来自福建不同双孢蘑菇产区(县级)的有害疣孢霉菌菌株进行了菌落特征、厚垣孢子形态特征观察并利用ISSR分子标记技术对它们进行了遗传多样性分析,结果表明:不同来源的有害疣孢霉菌的菌落特征和厚垣孢子形态特征均可归为3种类群;ISSR分子标记技术的分析结果也显示,16株有害疣孢霉菌菌株成3个进化分支,并与形态特征相对应,初步确定福建省有害疣孢霉菌出现3个类型的种群分化。     

The interaction between mushroom strains and fungicides in the control of dry bubble disease caused by Verticilliumfungicola

Five fungicides were compared for control of Verticilliumfungicola on six strains of the cultivated mushroom. The strains showed considerable differences both in their sensitivity to the fungicides and their susceptibility to infection. These factors complicated comparison of the fungicides, but benodanil was less effective than chlorothalonil against V. fungicola.     

The incidence of benomyl tolerance in Verticillium fungicola, Mycogone perniciosa and Hypomyces rosellus in mushroom crops

Of the 229 isolates of Verticillium fungicola examined 63 % were found to show some benomyl tolerance and 53% were very tolerant having EDg, values in excess of 50 ppm. There was a tendency for the tolerant isolates to have a slower growth rate than the sensitive ones on unamended potato dextrose agar (PDA) and forty-five isolates (19 %) showed growth stimulation at 5 ppm benomyl. No major differences were found in ten isolates of V. fungicola tested on benomyl, thiabendazole and thiophanate methyl agars or of twelve isolates compared on benomyl and carbendazim hydrochloride agars. Tolerant isolates of V. fungicola and higher levels of crop loss were linked in the east and north of the country but not in the south-east. Tolerance was not found in sixty-six isolates of Mycogone perniciosa or twenty-four of Hypomyces rosellus. Benomyl was used on 89 % of the farms in the survey either applied to the casing (34%) or as a spray (55 %) or both (10%).     

Allergic contact dermatitis caused by mushrooms

The first author is allergic to skin contact with mushrooms of Suillus americanus, S. granulatus, S. grevillei, S. luteus, or S. neoalbidipes. Symptoms develop between one and two days after contact and last for approximately a week, disappearing completely without treatment. Symptoms consist of reddening, swelling, and itching, at the sites of contact with pileus cuticle mucilage of all five species. Pore layer tissues (tested for S. americanus and S. luteus) also produced strong reactions, as did pileus trama (tested for S. luteus). Spores from spore prints (tested for S. americanus and S. luteus) produced no reaction. The reaction can be avoided by wearing gloves when handling allergenic species and by washing hands promptly after working with these species. Similar cases, reported from North America, Europe, and Russia, involve Agaricus, Boletus, Lactarius, Paxillus, Ramaria, and Suillus species. Several cases involve allergy to multiple species or genera. Symptom severity varies, presumably with intensity of exposure. In one case, symptoms were renewed following ingestion. Most cases demonstrate delayed allergic contact sensitivity.     

双孢蘑菇不同品种感染有害疣孢霉后防御酶活性变化

通过测定同一时期不同品种双孢蘑菇子实体接种和未接种情况下,子实体内苯丙氨酸解氨酶(PAL)、过氧化物酶(POD)、过氧化氢酶(CAT)和多酚氧化酶(PPO)等4种防御酶活性变化,为研究双孢蘑菇品种对有害疣孢霉Mycogone perniciosa的抗病性差异提供科学数据。结果表明:以双孢蘑菇As258、As2796和W192为材料,在接种处理后,各品种双孢蘑菇子实体内苯丙氨酸解氨酶(PAL)、过氧化物酶(POD)、过氧化氢酶(CAT)和多酚氧化酶(PPO)活性变化不同。双孢蘑菇W192品种4种酶活峰值最高,其次是As2796和As258。说明这4种酶与双孢蘑菇抗有害疣孢霉有一定的关联。     

Genetic Diversity Analysis of Mycogone perniciosa Causing Wet Bubble Disease of Agaricus bisporus in China Using SRAP

In this study, 38 Mycogone perniciosa isolates of Agaricus bisporus from the main production areas in China were analysed for investigating the genetic diversity using sequence‐related amplification polymorphism (SRAP). A total of 132 polymorphic bands were obtained, ranging in size from 100 to 1700 base pairs. According to the dendrogram produced by the unweighted pair‐group method with arithmetic average of similarity coefficients from SRAP data, all the tested strains were divided into four clusters at a 71.6% similarity level. Strains 1–3 and 13–17 from, respectively, Xichong County of Sichuan Province and Yongchang County of Gansu Province were clustered in the same clade; strains 4–8 and 9–12 from, respectively, Long Hai City of Fujian Province and Luoyang City of Henan Province clustered in sa second clade; strains 18–21 from Wuhan City of Hubei Province grouped together in a third cluster distinct from the other strains.     

双孢蘑菇疣孢霉病的发病过程及病原菌的核相研究

【目的】确定有害疣孢霉的传播途径,明确双孢蘑菇受有害疣孢霉侵染后发病症状和微观形态变化,以及有害疣孢霉的核相。【方法】将有害疣孢霉喷施于培养料及覆土材料的不同深度,观察记录双孢蘑菇的发病情况;将有害疣孢霉接种于不同生长阶段的双孢蘑菇子实体,观察记录其发病情况;使用光学显微镜及扫描电镜观察双孢蘑菇子实体受有害疣孢霉侵染前后的形态变化;通过DAPI(4′,6-二脒基-2-苯基吲哚)染色的方法对有害疣孢霉核相进行观察。【结果】将有害疣孢霉接种于培养料及覆土层的不同深度得到双孢蘑菇发病率如下:覆土层表面覆土层中间覆土与培养料交界处培养料中间层;有害疣孢霉可以侵染双孢蘑菇的任意阶段,将其接种于原基直径小于3 mm子实体表面时,得到不能正常分化的"马勃状"组织;对有害疣孢霉的侵染过程进行观察得到:其孢子可粘附于双孢蘑菇表面,并萌发长出芽管,接种处双孢蘑菇表面产生褐色病斑,双孢蘑菇菌丝体发生质壁分离,最后菌丝体膨大,细胞壁变薄甚至溢裂,菌丝体内部中空;有害疣孢霉产生两种类型的分生孢子,Ⅰ类无隔膜含1个细胞核;Ⅱ类具1隔膜含2个细胞核,2个细胞核被隔膜分开;细胞核的第1次有丝分裂发生于分生孢子母细胞中;厚垣孢子由上下2个细胞构成,上胞中含有2个细胞核。下胞含1–2个细胞核。有害疣孢霉的厚垣孢子萌发可产生1–2个芽管,芽管中细胞核的数目不断变化,一般0–2个细胞核。【结论】双孢蘑菇受其侵染后发生显著的细胞学变化;我们对有害疣孢霉做遗传分析时,进行单孢分离需挑取无隔膜的分生孢子为实验材料进行遗传分析。     

Biochemical changes during the development of witches' broom: the most important disease of cocoa in Brazil caused by Crinipellis perniciosa

Witches' broom disease (WBD) is caused by the hemibiotrophic basidiomycete fungus Crinipellis perniciosa, which is one of the most important diseases of cocoa in the western hemisphere. In this study, the contents of soluble sugars, amino acids, alkaloids, ethylene, phenolics, tannins, flavonoids, pigments, malondialdehyde (MDA), glycerol, and fatty acids were analysed in cocoa (Theobroma cacao) shoots during the infection and development of WBD. Alterations were observed in the content of soluble sugars (sucrose, glucose, and fructose), asparagine and alkaloids (caffeine and theobromine), ethylene, and tannins. Ethylene and tannins increased prior to symptom development and declined with the death of the infected tissues. Furthermore, MDA and glycerol concentrations were higher in infected tissue than in the controls, while fatty acid composition changed in the infected tissues. Chlorophylls a and b were lower throughout the development of the disease while carotenoids and xanthophylls dropped in the infected tissue by the time of symptom development. These results show co-ordinated biochemical alterations in the infected tissues, indicating major stress responses with the production of ethylene. Ethylene levels are hypothesized to play a key role in broom development. Some of the other biochemical alterations are directly associated with ethylene synthesis and may be important for the modification of its effect on the infected tissues.     

Witches' broom disease of cocoa Crinipellis perniciosa) in Ecuador

Two pathotypes of Crinipellis perniciosa were found in both eastern and western Ecuador. The cocoa strain was highly pathogenic to species of the genera Theobrotna and Herrania and caused the witches' broom disease. The liana strain was weakly or non-pathogenic to cocoa and its allies; it is endemic in the forests of Ecuador on lianes, shrubs and trees and is possibly parasitic in these tissues. The taxonomic position of the fungus is discussed.     

In vitro and in vivo screening of essential oils for the control of wet bubble disease of Agaricus bisporus

Proliferation of fungal pathogens, such as Mycogone perniciosa, can severely affect the yields of cultivated mushrooms, including that of the button mushroom, Agaricus bisporus. A reduction in the number of fungicidal products approved for commercial application is currently providing new challenges to the mushroom industry. Forty essential oils, seven pure terpenoids and one phenylpropanoid were screened in vitro to determine the abilities of these substances to inhibit the growth of M. perniciosa. The fungal growth medium of both A. bisporus and M. perniciosa was supplemented with each test substance at a concentration of 50 μL/L. Ten essential oils were further investigated at lower concentrations ranging from 5 to 40 μL/L. The main components of these oils were determined by GC–FID and GC–MS. Lemon verbena (Lippia citriodora), lemongrass (Cymbopogon citratus) and thyme (Thymus vulgaris) oils were found to substantially inhibit the growth of the pathogen, while demonstrating lower toxicity towards A. bisporus than any of the other oils tested. A preliminary in vivo trial using M. perniciosa-inoculated casings revealed that the preventative use of lemon verbena or thyme oils was able to control the development of the disease. A commercial trial using these oils, as well as two of their main components (nerol and thymol), at a concentration of 40 μL/L, revealed that none of these treatments were detrimental to the growth of the A. bisporus and an overall yield similar to that following application of a commercial fungicide (Chronos 450 SC) was obtained. These results suggest that essential oils or mixtures of selected pure components of essential oils may in future find application in button mushroom production, either as a substitute for synthetic fungicides or as an additional protective measure.     

Influence of nutrition on disease development caused by fungal pathogens: implications for plant disease control

A great deal of information is available in the literature on the effects of nutrition on disease development in plants and crops. However, much of this information is contradictory and although it is widely recognised that nutrition can influence disease in crops, limited progress has been made in the manipulation of crop nutrition to enhance disease control. Achieving this aim requires a sound understanding of the effects of fertilisation on nutrient levels and availability in crop tissues, and in turn, how the nutrient status of such tissues influences pathogen infection, colonisation and sporulation. Some of these details are known for a number of crop plants under controlled conditions, but very little of this type of information is available for crops under field conditions. This review focuses on nitrogen, sulphur, phosphorus, potassium and silicon, examines the availability of these nutrients in plant tissues to support pathogen growth and development, and reviews the effects of the different nutrients on disease development. The review also examines the potential for manipulating crop nutrition to enhance disease control in conventional and organic cropping systems.     

The immunobiology of mushrooms

There has been enormous interest in the biologic activity of mushrooms and innumerable claims have been made that mushrooms have beneficial effects on immune function with subsequent implications for inhibition of tumor growth. The majority of these observations are anecdotal and often lack standardization. However, there remains considerable data on both in vitro and in vivo effects that reflect on the potential of mushroom compounds to influence human immunity. A number of these effects are beneficial but, unfortunately, many responses are still characterized based on phenomenology and there is more speculation than substance. With respect to tumor biology, although many neoplastic lesions are immunogenic, tumor antigens frequently are self antigens and induce tolerance and many patients with cancer exhibit suppressed immune responses, including defective antigen presentation. Therefore, if and when mushroom extracts are effective, they more likely function as a result of improved antigen presentation by dendritic cells than by a direct cytopathic effect. In this review we attempt to place these data in perspective, with a particular focus on dendritic cell populations and the ability of mushroom extracts to modulate immunity. There is, at present, no scientific basis for the use of either mushrooms or mushroom extracts in the treatment of human patients but there is significant potential for rigorous research to understand the potential of mushrooms in human disease and thence to focus on appropriate clinical trials to demonstrate effectiveness and/ or potential toxicity.     

Pseudomonas tolaasii control by kasugamycin in cultivated mushrooms (Agaricus bisporus)

Pseudomonas tolaasii , causing brown blotch disease on the edible mushroom Agaricus bisporus , was effectively controlled by kasugamycin. An artificial infection was first established in the first flush, by inoculating the button-sized mushrooms of the first flush with a suspension of Ps. tolaasii. A 1% aqueous solution of kasugamycin supplied on the button-sized mushrooms of the second flush drastically reduced bacterial blotch symptoms on these mushrooms at picking stage. Disease incidence in the second flush in the control treatment (inoculated with Ps. tolaasii ) was composed of 18% lightly, 29% moderately and 10% heavily affected mushrooms, which totalled up to 57% affected. The 1% kasugamycin treatment significantly reduced total disease incidence to only 9% (lightly) affected. Single sodium hypochlorite treatments showed no result.     

The sterol composition of mushrooms

Sterols were isolated from ten mushrooms, Hygrocybe punicea, Lampteromyces japonicus, Leucopaxillus giganteus, Lentinus edodes, Flammulina velutipes, Amanita caesarea, Coprinus atramentarius, Russula foetens, R. nigricans and R. senecis. The compositions of the sterol fractions were determined by GLC, combined GC/MS, and ¹H NMR. Ergosterol was present in all the mushrooms. Other sterols found were 5α-cholest-7-en-3β-ol and ergosta-5,7-dien-3β-ol. Ergosta-5,8,22-trien-3β-ol was isolated from F. velutipes.     

Witches' broom disease of cocoa (Crinipettis perniciosa) in Ecuador.

Inoculation of cocoa with basidiospores of the witches' broom fungus Crinipellis perniciosa showed that stem, petiole and pulvinus tissues of unhardened flushes and also exposed wound surfaces were susceptible to infection in addition to the growing tip. Inoculation of flower cushions and young pods showed that carrot-shaped pods were usually the result of fertilisation of systemically infected flowers. In the absence of fertilisation such flowers produced parthenocarpic pods or chirimoyas. Transmis-sion of the fungus via infected beans was demonstrated and this may be a potent method of long-distance dispersal.