Mushroom is cultivated as one of the major economical crops in many areas in Korea. The total production has steadily increased from approximately 186,400 M/T in 2007 to 190,111 M/T in 2011. The button mushroom, Agaricus bisporus, showed the 5th production to 13,052 M/T in 2011. Several bacteria are known as the causal agents of diseases of the cultivated button mushroom (Agaricus bisporus) and oyster mushroom (Pleurotus ostreatus). Pseudomonas agarici is the causal agent of browning disease of commercial mushrooms. Colonization of mushroom caps by the bacterium results in development of browning lesions on pileus. These lesions are superficial brown spots and can be round or spreading. But P. agarici never caused sunken lesions and rotting of the mushroom tissues. Antagonists against P. tolaasii, HC42 were selected and their control efficacy of browning disease was investigated in this study. Antagonists against P. agarici, HC42 were selected and their control efficacy of browning disease was investigated in this study. After proceeding antagonistic test, HC42 was selected as a strong antagonist against P. agarici and the HC42 strain was identified as P. safensis with the cultural, physiological and biochemical properties and analysis of the 16S rRNA. The optimal culture medium for the antagonistic bacteria growth was determined as follows: 1.5% D-galactose, 1.5% yest extract, 1% NH4Cl, 1.5% KCl, and 1.0% L-asparagin at pH 6.0 at 25℃. Control efficacy of browning disease by HC42 treatment was 66% on Agaricus bisporus..

Mushroom is cultivated as one of the major economical crops in many areas in Korea. The total production has steadily increased from approximately 186,400 M/T in 2007 to 190,111 M/T in 2011. The button mushroom, Agaricus bisporus, showed the 5th production to 13,052 M/T in 2011. Several bacteria are known as the causal agents of diseases of the cultivated button mushroom (Agaricus bisporus) and oyster mushroom (Pleurotus ostreatus). Pseudomonas agarici is the causal agent of browning disease of commercial mushrooms. In this study, antagonistic bacteria to P. agarici were selected in vitro tests using confrontation bioassay and paper disk diffusion assay. The most active bacteria, HC12 were selected and their control efficacy of brown blotch disease was investigated in this study. After proceeding antagonistic test, HC12 was selected as a strong antagonist against P. agarici and the HC12 strain was identified as Alcaligenes sp. with the cultural, physiological and biochemical properties and analysis of the 16S rRNA. The optimal culture medium for the antagonistic bacteria growth was determined as follows: 0.5% dextrin, 1.5% yest extract, 1% NaNO3, 0.5% KH2PO4, and 1.5% L-asparagin at pH 9.0 at 30℃. Control efficacy of browning disease by HC12 treatment was 63% on Agaricus bisporus..

Mushroom is cultivated as one of the major economical crops in many areas in Korea. The total production has steadily increased from approximately 186,400 M/T in 2007 to 190,104 M/T in 2009. The oyster mushroom, Pleurotus ostreatus, showed the 2th production to 46,598 M/T in 2011. This study was carried out to investigated optimum mixing ratio of Korean natural Acer tegmentosum for production of functional oyster mushroom. Mycelial growth of Pleurotus ostreatus showed the highest growth at the media of 10% Acer tegmentosum and was decreased to increase of Acer tegmentosum addition ratio. But mushroom mycelial growth at Acer tegmentosum media was slower than that of the control. Total nitrogen and carbon source of Acer tegmentosum was 0.19% and 44.4%, respectively and C/N ratio was 234. Total nitrogen source and pH of substrates mixed with Acer tegmentosum were 2.7∼3.0 and 4.8∼5.0, respectively. The contents of P2O5 and K2O were decreased by increasing Acer tegmentosum but the contents of CaO, MgO and Na2O were no significant difference. The contents of Fe and Mn were decreased according to increasing of Acer tegmentosum, but the contents of Zn and Mn were no significant difference. Yields of fruiting body and diameter and thick of pileus were the highest at 10% Acer tegmentosum. The L value of pileus was the highest at the 30% Acer tegmentosum during mushroom harvest, but there was no significant difference in the a-value and the b-value. The contents of P2O5,, CaO, MgO and Na2O of fruiting body were no significant difference, but contents of Cu was decreased and Fe was increased according to increasing of Acer tegmentosum.

Mushroom is cultivated as one of the major economical crops in many areas in Korea. The total production has steadily increased from approximately 186,400 M/T in 2007 to 198,563 M/T in 2009. Several bacteria are known as the causal agents of diseases of the cultivated button mushroom (Agaricus bisporus) and oyster mushroom (Pleurotus ostreatus). Pseudomonas tolaasii is the causal agent of brown blotch disease of commercial mushrooms. Colonization of mushroom caps by the bacterium results in development of brown or cream lesions on pileus and stipe. These lesions are slightly concave spots and can be round or spreading. Antagonists against P. tolaasii, HC1 were selected and their control efficacy of brown blotch disease was investigated in this study. The HC1 isolate was selected as an inhibitor of tolaasin activity by bioassay on potato and it was identified as Pseudomonas sp. by the cultural, physiological and biochemical properties and analysis of the 16S rRNA. Control efficacy of brown blotch disease by HC1 treatment was 69% on Agaricus bisporus, 68% on Flammulina velutipes and 55% on pleurotus ostreatus respectively.

The total production has steadily increased from approximately 186,400 M/T in 2007 to 198,563 M/T in 2009. Winter mushroom, Flammulina velutipes, with 61,057913 M/T in 2009, showed the highest production. Several bacteria are known as the causal agents of diseases of the cultivated button mushroom (Agaricus bisporus) and oyster mushroom (Pleurotus ostreatus). Pseudomonas tolaasii is the causal agent of brown blotch disease of commercial mushrooms. Antagonists against P. tolaasii, HC5 were selected and their control efficacy of brown blotch disease was investigated in this study. After proceeding antagonistic test, HC5 was selected as a strong antagonist against P. tolaasii and the HC5 strain was identified as P. azotoformans with the cultural, physiological and biochemical properties and analysis of the 16S rRNA. Control efficacy of brown blotch disease by HC5 treatment was 73% on Agaricus bisporus, 78% on Flammulina velutipes and 71% on pleurotus ostreatus respectively.

Cobweb disease symptoms were observed in a mushroom farm in Buye, Korea during a disease survey in 2008-2011. Five isolates of Cladobotryum sp. were obtained from the infected caps and stipes. These isolates of Cladobotryum sp. were identified as C. mycophilum based on their morphological, cultural characteristics and analysis of the ITS sequences. Early symptoms were noticed as round, fleshy, yellowish brown lesions on mushroom caps. Late symptoms progressed when the parasitic fungus formed white cobweb circular colonies on dead or damaged pinheads, spread on the surface of the casing, and covered entirely fruiting bodies. Optimal temperature and pH for mycelial growth on MEA is 23℃ and 6.0. Microscopically the spores of the fungus are large and most 2~3 celled produced on vertically branched conidiophores. Mushroom caps turned dark brown and shrunk due to soft rot. Testing of sensitivity to selected fungicides showed that isolate was highly resistance to Mancozeb and Thiophanate-methyl, moderately sensitivity to Iprodione, and highly sensitivity to Benomyl, Prochloraz-Mn and Carbendazim.

Many basidiomycetes, especially mushroom species, thrive on saccharides that they obtain from the decomposition of cellulose, hemi-cellulose and or lignin. Cellulose is degraded by specific enzymes called cellulases. Cellulases play an important role in the biosphere by recycling cellulose, the most abundant carbohydrate produced by plants. Also cellulases have many potential biotechnologic and industrial applications. Detection of cellulose degrading activity is commonly performed on carboxymethylcellulose CMC medium in combination with a stain that reveals the degraded CMC. In order to efficiently screen the F. velutipes knockout library, obtained through Agrobacterium-mediated transformation (ATMT), for those important enzymes we compared two different staining methods i.e. Congo Red and Gram’s Iodine (as reported in R. C. Kasana et al 2008). The latter stain showed strongly enhanced detection in time and intensity, facilitating mass screening of our mutant database. Using Gram’s iodine and square petri dishes containing up to 9 colonies at a time we can now rapidly screen multiple mutants in a short period. We are going to find the genes. Inactivated genes of mutants with altered cellulase degradation activity will be identified and cloned for further analysis.

This study was conducted to determine changes in quality and microbial population of intact and fresh-cut button mushrooms (Agaricus bisporus). Freshly collected mushroom was cut into approximately 0.5 cm thick slices and washed in tap water or 100 ㎕L-1 chlorine solution (pH 7) for 60 seconds. Intact mushrooms were washed in the same condition as cut samples. Both intact and fresh-cut samples were then dried, packaged in 50㎛ poly ethylene bags, and stored at 5 ℃ for up to 9 days. Quality and microbial safety parameters such as gas composition, color, off-odor, visual quality, electrical conductivity, E. coli / coliform count, and total aerobic population were evaluated during storage. All sample packages exhibited a rapid depletion of O2 (to ~0 kPa) and accumulation of CO2 (10.3 to 12.6 kPa) throughout the storage period. No significant color difference was found between tap water and chlorine. However, chlorine treatment was effective in reducing off-odor development of intact and fresh-cut samples at the end of storage. The chlorine application also reduced aerobic bacterial populations. Both Intact and cut mushrooms had ≤ 5 log CFU/g of total aerobic plate counts until the end of storage. Fresh-cut samples regardless of chlorine sanitation had higher overall visual quality score than intact samples. Results indicated that fresh-cut mushrooms treated with chlorine maintained quality and shelf-life throughout the 9 day storage period.

This study was conducted to investigate optimum processing procedure of fresh-cut button mushrooms. The experiments were done with different processing parameters including washing method, washing time, sanitation, and cutting time. Fresh mushrooms were washed by swirling water (SW), lift type-immersion washing (LIW), or combined LIW and water spray (LI+WS). Mushroom samples were washed by LIW for 0, 1, 3, and 5 minutes separately. Mushrooms were sanitized with 0, 50, or 100 ㎕L-1 chlorine solution (pH 7) for 60 seconds. Mushrooms were sliced at different times (before washing, after washing, or after drying). The combined washing treatment, LIW+WS was effective in maintaining better appearance and higher Lightness color value among treatments. Optimum washing time to remove foreign materials and maintain color was 3 minutes when mushrooms were washed by LIW. Samples sanitized with 50 ㎕L-1 chlorine reduced initial aerobic bacterial population and had only slight residual chlorine odor. Fresh-cut mushrooms sliced after washing had the lowest loss among samples. The optimized washing, sanitation, and cutting time parameters can be used for sequential processing of fresh-cut button mushrooms.

We investigated 18 amino acid contents in the fruiting bodies of Agaricus strains to understand their variation in the harvesting periods. Total content of amino acid was different depending on the isolates. In the case of A. bitorquis and A. brunnescens, the total amino acid content increased and correlated with the harvesting periods. For commercial strains of A. bisporus, such as Yangsongi-505, Yangsongi-705 and commercial strain A collected in the market, it increased until the second harvesting period, but decreased in the third harvesting period indicating that these three isolates exhibit the exceptions for the general trend. Among isolates we used in our experiments, the isolate of A. brunnescens contained the highest and two isolates of A. bisporus were the lowest in total amino acids. We found two trends for the contents of each amino acid in the fruiting bodies of Agaricus spp.. One is the same with the trend of the total amino acid content and the amino acid content were largely correlated with the harvesting period. The other is the trend of increase of amino acid until the second harvesting period and decrease of amino acid in the third harvesting period, which was also shown in the total amino acid content of A. bisporus. Generally, the most amino acid contained in Agaricus was cysteine and followed by phenylalanine, glutamic acid, lysine, proline and histidine.

To understand the saccharide contents and quantity of winter mushroom (Flammulina velutipes) according to its growth temperature, we measured the saccharide contents at different growth temperature. In our results, the saccharide of its fruiting body turned out to be mainly composed of xylose, trehalose and mannitol in all treatments. In the other hand, Ribose, myo-inositol and sucrose were detected in some treatments. The quantity of trehalose decreased as the growth temperature increased with a variation of its quantity depending on the isolates used in the experiments. In the case of xylose and mannitol, detected in all treatments, the pattern of their quantities was not possible to be profiled and the pattern might be largely depending on the isolates. However, the quantities of xylose and mannitol were largely in a direct proportion and the fluctuation of their quantities was congruent with the exception of ASI 4103, ASI 4166 and ASI 4065. The xylose quantity of ASI 4103 and ASI 4166 increased until the temperature was up to 10℃ and decreased when the temperature was above 10℃. That of ASI 4065 decreased as the temperature rose and increased when above 13℃. The mannitol quantity of ASI　4065 and ASI 4166 decreased until the temperature was up to 10℃ and increased when the temperature was above 10℃. That of ASI 4103 increased as the temperature rose and decreased when above 13℃.

Hypsizygus marmoreus, belongs to Tricholomataceae of Agaricales, is widely cultured as the Beech mushroom in Japan. “Haemi” is the first variety developed by intra-specific crossing in Korea. It was improved with hybridization between monokaryotic strain derived from MKACC51987-8 and MKACC51988- 12. The optimum temperature of mycelial growth and fruiting body development were 23-25℃ and 11~17℃, respectively. The color of fruitingbody was grayish brown and cap type was umbrella. It suggest that 'Haemi' is new commercial variety for consumer who concern over healthy and tasty food

Flammulina velutipes, amongst others known as Winter Mushroom or Enokitake is an important economic crop in Asia. The tetrapolarity (having four mating types) of this mushroom obligates mating and results in self-sterile progeny that carries unique genetic traits, making understanding of the genetic base desirable for breeding. Moreover, mating type genes are significant for evolutionary studies as their high polymorphism benefits phylogenetic comparisons. This polymorphism further makes mating type genes interesting candidates for genetic markers that allow identification of specific strains. Mating type loci in Agaricomycotina are classically termed A and B and control two different developmental pathways [for a review see 1]. They consist of tightly linked subloci that encode multiallelic genes. MatA loci contain two groups of divergently transcribed homeodomain proteins (HD1 and HD2) and heterodimerization of HD1 with a non-self HD2 protein forms a functional transcription factor that activates the A pathway. MatB loci hold pheromones and pheromone receptors. Pheromone genes encode small precursor proteins that are characterized by a C-terminal CAAX motif. Pheromone receptors typically contain 7 membrane spanning regions and are coupled to G-proteins. Binding of a pheromone to a receptor, triggers splicing of the (trimeric) G-protein, which activates the B pathway. New genetic data from recent genome sequences is challenging the strict concepts of old mating type models in fungi. MatB loci turn out to be rather diverse and contain considerable varying numbers of pheromone receptors and associated pheromones. To this, pheromone receptors which are not linked to matB loci have now been reported for C. cincerea, S. commune and L. bicolor [2, 3]. Also the organization of the matA locus is less strictly conserved than anticipated. Though far more tightly maintained than the matB locus, substantial differences in HD gene numbers and overall organization are reported [2, 3]. These differences stress the importance of determination of the individual mating type systems from industrially important mushrooms to assist breeding. Our analysis of F. velutipes strain 4019-20 uncovered 7 pheromone receptors together with 3 pheromones. The matB-3 locus of this strain however, is defined by only a single pheromone receptor and pheromone gene and our data strongly indicates that a 2nd pheromone receptor recently lost its function. The other receptor genes are non mating type specific. Finally, we detected three homeodomain genes distributed over two distant subloci. These subloci have been separated by two large inversions. Strikingly the distant matA subloci in S. commune seem to be separated by inversions as well. Synthenic mapping of a large regions from Coprinus cinerea, Laccaria bicolor, S. commune and F. velutipes shows that the matA loci originate from a single locus in a common ancestor of S. commune and F. velutipes that is represented by L. bicolor and C. cinerea. [1] U Kües. Micr Mol Biol Rev 64, 316 (2000) [2] H Niculita-Hirzel, J Labbé, A Kohler, F le Tacon, F Martin, IR Sanders and U Kües. New Phytol 180, 329 (2008). [3] RA Ohm, JF de Jong, LG Lugones, A aerts, E Kothe, JE Stajich, RP de Vries, E Record, A Levasseur, SE Baker, KA Bartholomew, PM Couthino, S Erdmann, TJ Fowler, AC Gathman, V Lombard, B Henrissat, N Knabe, U Kües, WW Lilly, E Lindquist, S Lucas, JK Magnuson, F Piumi, M Rausdaskoski, A Salamov, J Schmutz, FWMr Schwarze, PA van Kuyk, JS Horton, IV Grigoriev and HAB Wösten. Nat. Biotechnol ISSN: 1087-0156 (2010).