Interactions between the pathogen Trichoderma harzianum TH2 and Agaricus bisporus in mushroom compost

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Molecular and physiological diversity among Verticillium fungicola var. fungicola and var. aleophilum

The genetic and physiological variability of Verticillium fungicola var. aleophilum responsible for Agaricus bisporus dry bubble disease in North America is well documented but little is known about the var. fungicola affecting European crops. Variability was assessed within this variety and compared with that reported for the var. aleophilum. Eighteen isolates of V. fungicola var. fungicola and four var. aleophilum isolates were analysed for DNA polymorphism, mycelial growth, response to biochemicals produced by A. bisporus, fungicide resistance, and pathogenicity assessed by direct inoculation on sporophore or casing contamination. RAPD and AFLP markers delineated three French isolates from a homogeneous group containing the other var. fungicola isolates, but no correlation could be drawn between DNA polymorphism and the various traits studied. The var. fungicola isolates were more susceptible than the var. aleophilum isolates to the antibiosis effect of A. bisporus. Only mycelial growth rate at 23 °C could explain the variability in aggressiveness among the European isolates. The putative effect of the post-incubation temperature on contamination during mushroom cultivation was discussed. This work emphasized that, like the American var. aleophilum, the var. fungicola in Europe is genetically homogeneous, but physiological diversity exists, especially in France where it could be related to less standardized cultural practices

Factors influencing the competitive saprophytic ability of Trichoderma harzianum Th2 in mushroom (Agaricus bisporus) compost

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Green mold disease: adaptation of Trichoderma harzianum Th2 to mushroom compost

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Verticillium disease of Agaricus bisporus: Variations in host contribution to total fungal DNA in relation to symptom heterogeneity

cited By 11International audienceThe pathogenic fungus Verticillium fungicola, responsible for dry bubble disease of the common mushroom Agaricus bisporus, causes various symptoms on its host, bubbles (undifferentiated spherical masses), bent and/or split stipes (blowout) and spotty caps. Host DNA quantification by real-time PCR was used to observed relationships between the type of symptom and the relative amount of A. bisporus and V. fungicola in diseased mushrooms. Verticillium fungicola is involved in bubble formation but does not appear to regulate its growth. Quantifications in bubbles and stipe-bubbles (morphology between bubble and sporophore with stipe blowout) showed that the pathogen has no effect on the growth of undifferentiated host hyphae but prevents morphological differentiation if not initiated and stops it when initiated hyphae are affected. Mushrooms with stipe blowout exhibiting both mature and abortive lamellae reveal that V. fungicola has a restricted area of action in host tissues. Despite their visual aspect, healthy looking parts of mushrooms showing spots or stipe blowout were actually contaminated. Discolouration and symptom development are two distinct events. The colour of the tissues was correlated to the percentage of A. bisporus DNA, suggesting that discolouration is not an efficient defensive mechanism, and occurs at the time V. fungicola developed enough to induce tissues necrosis. © 2007 KNPV

Molecular and physiological diversity among Verticillium fungicola var. fungicola

cited By 11International audienceThe genetic and physiological variability of Verticillium fungicola var. aleophilum responsible for Agaricus bisporus dry bubble disease in North America is well documented but little is known about the var. fungicola affecting European crops. Variability was assessed within this variety and compared with that reported for the var. aleophilum. Eighteen isolates of V. fungicola var. fungicola and four var. aleophilum isolates were analysed for DNA polymorphism, mycelial growth, response to biochemicals produced by A. bisporus, fungicide resistance, and pathogenicity assessed by direct inoculation on sporophore or casing contamination. RAPD and AFLP markers delineated three French isolates from a homogeneous group containing the other var. fungicola isolates, but no correlation could be drawn between DNA polymorphism and the various traits studied. The var. fungicola isolates were more susceptible than the var. aleophilum isolates to the antibiosis effect of A. bisporus. Only mycelial growth rate at 23 °C could explain the variability in aggressiveness among the European isolates. The putative effect of the post-incubation temperature on contamination during mushroom cultivation was discussed. This work emphasized that, like the American var. aleophilum, the var. fungicola in Europe is genetically homogeneous, but physiological diversity exists, especially in France where it could be related to less standardized cultural practices. © 2006 The British Mycological Society

The medicinal Agaricus mushroom cultivated in Brazil: Biology, cultivation and non-medicinal valorisation

cited By 29International audienceSun mushroom is a cultivated mushroom extensively studied for its medicinal properties for several years and literature abounds on the topic. Besides, agronomical aspects were investigated in Brazil, the country the mushroom comes from, and some studies focus on the biology of the fungus. This review aimed to present an overview of the non-medicinal knowledge on the mushroom. Areas of commercial production and marketing trends are presented. Its specific fragrance, taste, nutritional value and potential use of extracts as food additives are compared to those of the most cultivated fungi and laboratory models. The interest of the mushroom for lignocellulosic enzyme production and source of biomolecules for the control of plant pathogens are shown. Investigation of genetic variability among cultivars is reported. Growing and storage of mycelium, as well as cultivation conditions (substrate and casing generally based on local products; indoor and outdoor cultivation; diseases and disorders) are described and compared to knowledge on Agaricus bisporus. © 2011 Springer-Verlag

Expression of phenol oxidase and heat-shock genes during the development of Agaricus bisporus fruiting bodies, healthy and infected by Lecanicillium fungicola

cited By 17International audienceThe fungal pathogen Lecanicillium fungicola (formerly Verticillium fungicola) is responsible for severe losses worldwide in the mushroom (Agaricus bisporus) industry. Infected crops are characterised by masses of undifferentiated tissue (bubbles) growing in place of sporophores. The expression of three laccase genes (lcc1, lcc2 and lcc3), two tyrosinase genes (AbPPO1 and AbPPO2) and the hspA gene encoding a heat-shock protein known to be potentially associated with host-pathogen interaction was investigated in mycelial aggregates and during the development of healthy sporophores and bubbles of a susceptible cultivar. The lcc3, AbPPO2 and hspA genes were each expressed at different levels at the different stages of sporophore morphogenesis, whilst they showed a stable expression throughout bubble development. The transcript levels were similar in bubbles and at the first developmental stage of healthy fruiting bodies, both showing no tissue differentiation. These observations suggest that lcc3, AbPPO2 and hspA are associated with A. bisporus morphogenesis. Comparing the expression of the hspA gene in three susceptible and three tolerant strains showed that the latter displayed a higher level of transcript in the primordium, which is the stage receptive to the pathogen. The six strains exhibited a comparable expression in the vegetative mycelium, non-receptive to L. fungicola. © 2009 Springer-Verlag