The green mould disease global threat to the cultivation of oyster mushroom (Pleurotus ostreatus): a review (original) (raw)
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Since the early 80s, several reports have been published in Europe and North America about green mould infections of cultivated Agaricus bisporus, and the causative agents were described as Trichoderma aggressivum f. europaeum and T. aggressivum f. aggressivum, respectively. In the latest years the green mould disease of Pleurotus spp. caused by Trichoderma also occurred in several countries, and the most serious cases were reported in South Korea, Italy, Hungary and Romania. The fungi responsible for the green mould disease of oyster mushroom were found to be different from T. aggressivum based on their cultural, morphological, physiological and molecular properties, therefore they have been described as the new species T. pleurotum and T. pleuroticola. Since the green mould disease of P. ostreatus is spreading fast worldwide, the aim of this work was to develop a PCR-based technique for the rapid detection of the causative agents.
…, 2007
E., Vágvölgyi, C., and Kredics, L. 2006. Green mould diseases of Agaricus and Pleurotus are caused by related but phylogenetically different Trichoderma species. Phytopathology Producers of champignon (Agaricus bisporus) and oyster mushroom (Pleurotus ostreatus) are facing recent incidents of green mould epidemics in Hungary. We examined 66 Trichoderma strains isolated from Agaricus compost and Pleurotus substrate samples from three Hungarian mushroom producing companies by a PCR-based, diagnostic test for T. aggressivum, sequence analysis of the internal transcribed spacer regions 1, 2 and (selectively) of the 4 th and 5 th intron of translation elongation factor 1, and RFLP of mitochondrial DNA. Seven Trichoderma species were identified [numbers of isolates given in brackets]: T. aggressivum f. europaeum [17], T. harzianum [3], T.
GREEN MOULD DISEASE OF OYSTER MUSHROOM IN HUNGARY AND ROMANIA: ECOPHYSIOLOGY OF THE CAUSATIVE AGENTS
2009
The green mould disease of oyster mushroom (Pleurotus ostreatus) has been recently reported to cause great crop losses in Hungary and Romania. Trichoderma pleurotum and Trichoderma pleuroticola, the lately described fungal species responsible for the disease are present in both countries. The presented analysis has revealed that the growth of T. pleurotum shows a narrower temperature range (15-30°C) than that of T. pleuroticola (10-35°C). Acidic and neutral pH values and higher water activities were found to favour the growth of both pathogens. These data provide useful information for mushroom growers to optimize the ecophysiological parameters during oyster mushroom cultivation.
FEMS microbiology …, 2009
Green mold of Pleurotus ostreatus, caused by Trichoderma species, has recently resulted in crop losses worldwide. Therefore, there is an emerging need for rapid means of diagnosing the causal agents. A PCR assay was developed for rapid detection of Trichoderma pleurotum and Trichoderma pleuroticola, the two pathogens causing green mold of P. ostreatus. Three oligonucleotide primers were designed for identifying these species in a multiplex PCR assay based on DNA sequences within the fourth and fifth introns in the translation elongation factor 1a gene. The primers detected the presence of T. pleurotum and/or T. pleuroticola directly in the growing substrates of oyster mushrooms, without the need for isolating the pathogens. The assay was used to assess the presence of the two species in natural environments in which P. ostreatus can be found in Hungary, and demonstrated that T. pleuroticola was present in the growing substrates and on the surface of the basidiomes of wild oyster mushrooms. Other Trichoderma species detected in these substrates and habitats were Trichoderma harzianum, Trichoderma longibrachiatum and Trichoderma atroviride. Trichoderma pleurotum was not found in any of the samples from the forested areas tested in this study.
Applied and …, 2007
The worldwide commercial production of the oyster mushroom Pleurotus ostreatus is currently threatened by massive attacks of green mold disease. Using an integrated approach to species recognition comprising analyses of morphological and physiological characters and application of the genealogical concordance of multiple phylogenetic markers (internal transcribed spacer 1 [ITS1] and ITS2 sequences; partial sequences of tef1 and chi18-5), we determined that the causal agents of this disease were two genetically closely related, but phenotypically strongly different, species of Trichoderma, which have been recently described as Trichoderma pleurotum and Trichoderma pleuroticola. They belong to the Harzianum clade of Hypocrea/Trichoderma which also includes Trichoderma aggressivum, the causative agent of green mold disease of Agaricus. Both species have been found on cultivated Pleurotus and its substratum in Europe, Iran, and South Korea, but T. pleuroticola has also been isolated from soil and wood in Canada, the United States, Europe, Iran, and New Zealand. T. pleuroticola displays pachybasium-like morphological characteristics typical of its neighbors in the Harzianum clade, whereas T. pleurotum is characterized by a gliocladium-like conidiophore morphology which is uncharacteristic of the Harzianum clade. Phenotype MicroArrays revealed the generally impaired growth of T. pleurotum on numerous carbon sources readily assimilated by T. pleuroticola and T. aggressivum. In contrast, the Phenotype MicroArray profile of T. pleuroticola is very similar to that of T. aggressivum, which is suggestive of a close genetic relationship. In vitro confrontation reactions with Agaricus bisporus revealed that the antagonistic potential of the two new species against this mushroom is perhaps equal to T. aggressivum. The P. ostreatus confrontation assays showed that T. pleuroticola has the highest affinity to overgrow mushroom mycelium among the green mold species. We conclude that the evolutionary pathway of T. pleuroticola could be in parallel to other saprotrophic and mycoparasitic species from the Harzianum clade and that this species poses the highest infection risk for mushroom farms, whereas T. pleurotum could be specialized for an ecological niche connected to components of Pleurotus substrata in cultivation. A DNA BarCode for identification of these species based on ITS1 and ITS2 sequences has been provided and integrated in the main database for Hypocrea/Trichoderma (www.ISTH.info).
2007
Green mould disease in Oyster mushroom (Pleurotus ostreatus) caused by Trichoderma harzianum results in considerable inhibition of growth of mycelium and fruit bodies of Oyster mushroom lowering the yield substantially. The study examined how mushroom growth is inhibited while T. harzianum growth is accelerated. Diseased mushroom bags were collected from mushroom houses within the Kandy district and T. harzianum was isolated. The most dominant strain was identified as T. harzianum biotype II (Th2) from the colony and growth characteristics. When the two fungi were grown on dual culture, T. harzianum overgrew the colonies of P. ostreatus rapidly. Diffusible metabolites produced by T. harzianum in culture significantly reduced the growth of P. ostreatus. Volatile metabolites of T. harzianum slightly stimulated the mycelial growth of P. ostreatus initially but P. ostreatus soon reverted to its normal growth. Growth of T. harzianum was not stimulated by P. ostreatus metabolites. Underst...
Ceylon Journal of Science (Biological Sciences)
Green mould disease in Oyster mushroom (Pleurotus ostreatus) caused by Trichoderma harzianum results in considerable inhibition of growth of mycelium and fruit bodies of Oyster mushroom lowering the yield substantially. The study examined how mushroom growth is inhibited while T. harzianum growth is accelerated. Diseased mushroom bags were collected from mushroom houses within the Kandy district and T. harzianum was isolated. The most dominant strain was identified as T. harzianum biotype II (Th2) from the colony and growth characteristics. When the two fungi were grown on dual culture, T. harzianum overgrew the colonies of P. ostreatus rapidly. Diffusible metabolites produced by T. harzianum in culture significantly reduced the growth of P. ostreatus. Volatile metabolites of T. harzianum slightly stimulated the mycelial growth of P. ostreatus initially but P. ostreatus soon reverted to its normal growth. Growth of T. harzianum was not stimulated by P. ostreatus metabolites. Underst...
A challenge to mushroom growers: the green mould disease of cultivated champignons
The aim of this minireview is to give an overview of the literature about the green mould disease of cultivated champignons (Agaricus bisporus) caused by Trichoderma species. The first significant green mould epidemic appeared in Northern Ireland in 1985, which was quickly followed by subsequent outbreaks in several countries. The symptoms of green mould appear as large patches of compost turning green rapidly. Epidemic outbreaks are due to two varieties of the species T. aggressivum. This species competes efficiently for space and nutrients, produces extracellular enzymes, toxic secondary metabolites and volatile organic compounds, which results in drastical crop losses. The natural habitat of T. aggressivum is still unknown. Possible routes of infection include the air, vehicles, contaminated clothes and animal vectors. A primer pair for the specific identification of T. aggressivum is available for the fast and cheap monitoring of the causal agent. Possible management strategies include the application of disinfectants, pasteurization, adjustment of casing pH, chemical treatments, biological control by antagonistic bacteria as well as the cultivation of resistant Agaricus varieties.
Molecular characterization of Trichoderma taxa causing green mould disease in edible mushrooms
2006
Trichoderma taxa associated with green mould disorder of edible mushrooms were isolated from both fruit bod- ies and substrates of Agaricus bisporus, A. b itorquis, Calocybe indica, Ganoderma lucidum, Lentinula edodes, Pleurotus sajor-caju, and Volvariella volvacea. Emerged fruiting bodies in the affected portion of the substrate were badly spotted, brownish in colour and reduced in both growth rate and yield performance. Microscopic examination of cultures revealed significant differences in fungal morphology, but were difficult to de signate as Trichoderma species. The nucleotide sequence compari- sons of 5.8S rRNA gene using BLAST network facili- tated molecular identification and genetic cataloguing of 18 Trichoderma isolates into two taxa, namely T. harzianum and T. virens . RAPD primers exhibited both inter- and intra-specific variations among the test isolates and separated them into eight distinct phylog e- netic sub -clades. The present study underlines the p o- tential thr...