Earticle

Pleurotus ostreatus, the oyster mushroom, is one of the most important edible mushrooms. It is especially susceptible to bacterial blotch disease, which is caused by Pseudomonas tolaasii. In order to develop bacterial blotch disease-resistant transgenic mushroom, NUECIN cDNA, a gene for an antibacterial peptide cloned from Bombyx mori, was overexpressed in Pleurotus ostreatus. NUECIN cDNA was fused to the β-TUBULIN promoter of oyster mushroom and co-transformed with the pTRura3-2 vector into the uracil auxotrophic mutant strain. Twelve transformants containing the Nuecin gene were identified by genomic PCR and Southern blot analysis. NUECIN gene expression was confirmed by Northern blot analysis. Three transformants showed the transcriptional expression of the gene. However, we could not detect expression of the protein in the transformants. This study showed the possibility of transgenic mushroom development for disease resistance.

MST247ns(Hwaseong #2) was developed by the method of Di-mon mating between monokaryotic strains derived from “Hwaseong #1” and dikaryotic strain “Suhan #1”. The optimum temperature of mycelial growth was 25-30℃ . The optimum temperature of primordia formation and fruiting body development were 8-15℃ and 9-14℃. Days of primordia formation were 4-5 days later Suhan #1. The stipes were longer than “Suhan #1”. The surfaces of stipe were white and the tissues got harder and more elastic. Therefore, the management of growth environment under low temperatures was relatively easy and storability got much better.

We aimed to develop a new variety of Neolentinus lepideus from about forty strains by bag culture. To this end, “Solhyang” which means pine smell in Korean was selected as a new commercial variety of N. lepideus. N. lepideus have yellow pileus and pine smell, which characteristics make a favorable impression on the far east Asia, Korean and Japanese. The optimum temperatures for mycelial growth and fruit body development ranged 26~32℃ and 18~20℃, respectively. The required periods of mycelial incubation and fruit body growth were 30 days and 7 days, respectively. The fresh weight of fruit body was 115g/kg with pine sawdust and corn meal power(9:1, v/v) substrate.

This study was carried out to select the suitable substrates for bag cultivation of Lentinula edodes. We investigated the optimal additive materials and its mixing ratio in bag cultivation of L. edodes, Sanjo 701 ho. The suitable substrates for L. edodes bag cultivation were oak sawdust as new material plus deffatted corn flour, and corn husk as an additive at the ratio 8:1:1(v/v), as the result of shorter mycelial growth, higher biological efficient, and a higher yield than any other substrates.

Trichoderma disease of oyster mushroom has not been effectively detected in the field for testing its resistance against the disease with its varieties. In this study, we investigated the methods to detect its resistance in the laboratory by using media, which enables us to understand the relevant characteristics (e.g., lysis, toxin enzyme, mycelial growth rate). In coculturing with strains of Trichoderma and oyster mushroom, it is possible to observe the difference in the resistance of oyster mushroom against Trichoderma with the phenomena of barrage reaction, overgrowth and lysis. We also observed the inhibition of mycelial growth of oyster mushroom using the dilution method with 48-well plate, but could not observed the inhibition of mycelial growth using the filter paper method of cultural supernatant. In simultaneously culturing both Trichoderma and oyster mushroom, it was possible to detect the inhibition of the mycelial growth of oyster mushroom, but Trichoderma mycelium did not overgrow against oyster mushroom. We found that the pathogenicity was efficient in using solid medium with the phenomena of overgrowth and lysis by inoculating Trichoderma on top of mycelia of oyster mushroom. In conclusion, the methods (e.g., coculture method, dilution method with 48 -well plate, post-inoculation method) are recommended to detect the resistance of oyster mushroom against Trichoderma disease.

The mushroom Agrocybe aegerita was analyzed to evaluate the nutritional value of this potential food and to enhance the cultivation and consumption. Among the nutritional compositions of Agrocybe aegerita, contents of crude proteins, crude fats and ashes were 38.3%, 3.0% and 8.2% respectively. The contents of potassium and phosphorus were higher than that of other minerals. Total phenolics contents were 65.2㎍/㎖ and 46.0㎍/㎖ in water extract and ethanol extract, respectively. Total flavonoids were estimated as 12.5㎍/㎖ contents of water extract and ethanol extract were 7.1㎍/㎖. Free radical scavenging activity against DPPH of ethanol extract, 79.2% was higher than that of water extract(58.2%). The contents of total phenolics, flavonoids and antioxidant activity by the DPPH scavenging activity of Agrocybe aegerita were higher than those of Pleurotus eryngii and Pleurotus ostreatus. The tyrosinase inhibitory activity showed 63.2% and 65.0% in water extract and ethanol extract, respectively. Angiotensin converting enzyme inhibitory activity of water extract was 78.7% and 75.0% in ethanol extract. In this study, Agrocybe aegerita has abundant essential nutrients and thus is good source of functional health food.

Winter mushroom was monitored to investigate the influence of storage temperature on its quality during the storage and distribution phase. In measuring its quality, the contents of saccharides were quantified with its fruiting bodies using HPLC. Although it has been known to be difficult to separate saccharide isomers, our results indicated that Grace Prevail carbohydrate ES 5μcolumn was the best in the separation to analyze the saccharide out of six columns used in this study. In our results, xylose was the main component of saccharide in the fruiting body of winter mushroom(White line mushroom:47.68㎎/g, brown line mushroom: 63.28㎎/g). In long-term storage, the total amount of saccharide tended to increase, but trehalose content of the disaccharide decreased. In comparison with the paramount amount of lactose and myo-inositol contents in long-term storage at 4℃, lactose wasn’t detected when stored at -1℃.

Two Inonotus species newly found in Japan were described. I. formosanus T.T. Chang & W.N. Chou was identified with the following characters; thin basidocarps with hispid when young and later the erect hyphae agglutinate to scrupose tuft, pore surface light yellow to rusty brown later, absence of setal hyhpae, ventricose hymenial setae, and small ellipsoid, hyaline to yellowish basidiospores. I. nodulosus (Fr.) P. Karst. was identified with the following characters; basidocarps nodulose, wart-like shape, scrupose to warted by agglutinated hayphae, margin up to 5 mm, pore surface cinnamon to rusty brown when dry with a whitish or silvery shine, absence of setal hyphae, acute straight hymenical setae, ellipsoid to subglobose basidiospores, which are weakly dextrinoid in Melzer’s reagent.