Pleurotus green mould disease: a PCR-based test for the rapid detection of the causative agents, Trichoderma pleurotophilum and Trichoderma fulvidum (original) (raw)
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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...
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...
During the last two decades, several case reports have been published worldwide about green mould infections of cultivated Agaricus bisporus, and the causative agents were identified as Trichoderma aggressivum. More recently, the green mould disease of Pleurotus spp. caused by Trichoderma has also been reported in several countries. Pleurotus ostreatus is the third-most important commercially grown basidiomycete worldwide, and its production is being increasingly affected by green mould infections causing great crop losses. The fungi responsible for the green mould disease of Pleurotus proved to be different from T. aggressivum, based on their cultural, morphological, physiological and molecular properties. e causative agents of the disease have been described as the new species Trichoderma pleurotum S.H. Yu & M.S. Park and Trichoderma pleuroticola S.H. Yu & M.S. Park, and the isolates from other countries were shown to be identical to them. The aim of this article is to give an ove...
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.
UreA, the major urea/H+ symporter in Aspergillus nidulans
Fungal Genetics and Biology, 2010
We report here the characterization of UreA, a high-affinity urea/H + symporter of Aspergillus nidulans. The deletion of the encoding gene abolishes urea transport at low substrate concentrations, suggesting that in these conditions UreA is the sole transport system specific for urea in A. nidulans. The ureA gene is not inducible by urea or its precursors, but responds to nitrogen metabolite repression, necessitating for its expression the AreA GATA factor. In contrast to what was observed for other transporters in A. nidulans, repression by ammonium is also operative during the isotropic growth phase. The activity of UreA is down-regulated post-translationally by ammonium-promoted endocytosis. A number of homologues of UreA have been identified in A. nidulans and other Aspergilli, which cluster in four groups, two of which contain the urea transporters characterized so far in fungi and plants. This phylogeny may have arisen by gene duplication events, giving place to putative transport proteins that could have acquired novel, still unidentified functions.
Fungal Genetics and Biology, 2014
Transport assays allow the direct kinetic analysis of a specific transporter by measuring apparent K m and V max values, and permit the characterization of substrate specificity profiles through competition assays. In this protocol we describe a rapid and easy method for performing uptake assays in the model filamentous ascomycete Aspergillus nidulans. Our method makes use of A. nidulans germinating conidiospores at a defined morphological stage in which most transporters show maximal expression, avoiding technical difficulties associated with the use of mycelia. In combination with the ease of construction of genetic null mutants in A. nidulans, our method allows the rigorous characterization of any transporter in genetic backgrounds that are devoid of other transporters of similar specificity. Here, we use this method to characterize the kinetic parameters and the specificity profile of UapC, a uric acid-xanthine transporter present in all ascomycetes and member of the ubiquitous Nucleobase-Ascorbate Transporter family, in specific genetic backgrounds lacking other relevant transporters.
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...
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).
Molecular Microbiology, 2009
The function of seven paralogues phylogenetically related to the Saccharomyces cerevisiae Fur4p together with a number of functionally related transporters present in Aspergillus nidulans has been investigated. After deletion of the cognate genes we checked the incorporation of radiolabelled substrates, utilization of nitrogen sources, resistance to toxic analogues and supplementation of auxotrophies. FurA and FurD encode allantoin and uracil transporters respectively. No function was found for FurB, FurC, FurE, FurF and FurG. As we failed to identify Fur-related transporters for uridine, pyridoxine or thiamine, we deleted other possible candidates for these functions. A FCY2-like gene carrying in its 5Ј UTR a putative thiamine pyrophosphate riboswitch, and which encodes a protein similar to the pyridoxine transporter of yeast (Tpn1p), does not encode either a major thiamine or a pyridoxine transporter. CntA, a member of the concentrative nucleoside transporter family, is a general nucleoside permease, while no function was found for PnpA, a member of the equilibrative transporter family. Phylogenetic analysis shows that within the ascomycetes, the same transport activity could be catalysed by totally unrelated proteins and that within the Fur subfamily convergent evolution towards uracil and allantoin transport activity has occurred at least three and two independent times respectively.