Mojgan Parvandi; Mohammad Farsi; Mohsen Ashrafi
Abstract
Introduction: The white button mushroom does not produce remarkable yield in the third flash. Nutritional deficiency and the inability of this mushroom to efficient use of compost are mentioned as its reasons. Basically, compost includes two major food components, lignocellulose and microbial biomass. ...
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Introduction: The white button mushroom does not produce remarkable yield in the third flash. Nutritional deficiency and the inability of this mushroom to efficient use of compost are mentioned as its reasons. Basically, compost includes two major food components, lignocellulose and microbial biomass. But this microbial biomass provides just 10% of button mushroom food needs. According to research studies, differentenzymes in both white button mushroom and oyster mushroom are responsible for decomposition of lignin compounds in compost media, from begin of mycelium grows to the end of fruiting. Lacasse, manganese peroxidase, lignin peroxidase, glyoxal oxidase enzymes contribute to degradation of lignin compounds in degradation mushroom has proven by researchers however itis dependent on mushroom types. Manganese peroxidase enzyme (EC. 1.11.1.13) is an extracellular parser lignin enzyme that has a central peroxidase core. Manganese peroxidase enzyme oxidizesMn2+ to Mn3+ and then Mn3+ oxidizes phenolic structure to fonoxile radical. Produced Mn3+ is very active and makes complex by chelating organic acids that is produced by mushrooms such as oxalate or malate. Mn3+ ions become stable by helping of these chelates and it can penetrate through materials such as wood. On the other hand, in recent years, plant biotechnology provides new solutions for old problems such as use of microorganisms, particularly using bacteria for gene transfer and improvement of superlatives. For a sample of this method, Agrobacterium-mediated transformation system can be noted. In addition, the use of suitable promoters for heterologous genes expression in suitable hosts is an important strategy in functional biotechnology that has been raised in edible mushroom genetic engineering. The lack of efficient and sufficient use of compost, low power of white button mushroom in competition with other rivals, lack of yield per area unit due to production costs, pests and diseases, low flexibility and adaptability with environmental conditions changes are some of the problems that the mushroom reformers are faced. Unlike the great efforts made by researchers, conventional breeding techniques to produce the A. bisporus mushroom only have been led to produce a few new races. Therefore, todays some problems associated with traditional methods of breeding of edible mushrooms, including the need to provide races that have desired characteristics, the traditional method performance tests and low chances of success in the transfer of important agronomic characteristics such as functionality and disease resistance. So, they almost have been replaced with new biotechnology methods. Anexample of this method is to manipulateproperties transformation for the particular purpose. Modification of both expression or type of lignin degrading enzyme are possible solutions to deal with this problem, but these are not applicable or are difficult to be done with traditional breeding programs. In recent years, gene transformation mediated with Agrobacterium routinely is used for gene transformation to mushrooms and is proposed as a method for removing limitations of white button mushroom breeding.
Materials and Methods: In this research, the oyster mushroom strain Florida was used as the source of manganese peroxidase (mnp) gene and white button mushroom strain 737 gill and cap tissue were used as transformation host. Agrobacterium strain LBA4404 harbors p133H88-FM plasmid thatcontainsmnp gene of oyster mushroom and also hph gene under control of gpdII promoter of the button white mushroom strain IM008 was used as a transformer. Selection medium containing 30 mg/ml Hygromycin B and was used for selecting transformed explants. To confirm transformation, PCR with specific primers of mnp and hph genes was performed on genomic DNA of selected colonies.
Results and Discussion: Results showed the gill tissue explants, with transformation rate 5%, have a better response to applied transformation method than cap tissue explants, with transformation rate zero percent. As expected, polymerase chain reaction with specific primers ofhph and mnp genes amplified 1049 and 1086 bp fragments and verified the transformation of mycelium's grown on selection medium. It seems that Bacterial strain and also used plasmid were one of the responses for observed low rate transformation which is in accordance with leach and co-workers study. Finally, we could propose that cap tissue is more suitable for further gene transformation of this mushroombecause of high transformation rate of cap tissue.
Mohsen Alipoor; Mohammad Farsi; Amin Mirshamsi Kakhki
Abstract
The white button mushroom, Agaricus bisporus, is a commercially important cultivated filamentous fungus. Strain stability is of great importance to both spawn producers and mushroom growers. Mushroom strains are usually propagated via vegetative method on nutritionally rich substrates. Abnormal growth ...
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The white button mushroom, Agaricus bisporus, is a commercially important cultivated filamentous fungus. Strain stability is of great importance to both spawn producers and mushroom growers. Mushroom strains are usually propagated via vegetative method on nutritionally rich substrates. Abnormal growth and poor yield are the consequences of this replication method. The reason for this phenomenon is still unknown. The use of molecular markers is one way of assessing and understanding the genetic changes. In this study, for the first time we reported the application of amplified fragment length polymorphism (AFLP) marker to assess genetic variation in single spore progeny and to assist selection of superior cultivars based upon the use of monosporous cultures of A. bisporus commercial strain, Holland737. We isolated 30 single spores that differed in growth rate, productivity and AFLP inheritance pattern. Nine EcoRI / TaqI primer combinations identified a total of 353 AFLP bands from 19 single-spore isolates, of which 53 were polymorphic. Results showed that the single spore selection is an effective method for strain improvement in A. bisporus, so that two isolates averagely performed 47% increased yield over the maternal strain and AFLP showed enough sensitivity to detect polymorphisms among single spore isolates.
