Earticle

Pleurotus ostreatus ‘Miso’ is a mutant strain showing white color in pileus from the known parent strain ‘Wonhyeong 1’. Shape and several other characters also vary with culture conditions. Mating experiments were performed to understand interstrain mating relationship using monokaryons of the parent and the mutant strains. All monokaryons were grown from single spores isolated from freshly collected fruit bodies. Pairings were performed in 90 mm petri dishes on PDA. They were allowed to grow at 25 until two fronts of the advancing mycelia met and developed a conspicuous contact zone. The contact zone and the outer edges of paired colonies on each plate were examined for clamp connections. The parent and the mutant resulted in tetrapolar incompatibility in intrastrain crosses. In interstrain crosses, each monokaryotic tester strain of the parent strain was out-crossed to monokaryotic tester strains of the mutant. As a result of these crosses it was found that both strains share the same A and B incompatibility factors yielding 25% compatibility.

To develop new variety of oyster mushroom, 63 intra-specific hybrids between the strain Suhan and #Nongi201 were developed using hyphal anastomosis technique in 2004. The Po2008-275 hybrid between the dikaryon strain 04-154(Suhan x #Nongi201) and the monokaryon strain derived from ASI2487 were developed using hyphal anastomosis in 2008. The Po2008- 275 was shown the best cultural characteristics, selected to be a new variety and named as ‘Guseol’. The new commercial strain, ‘Guseol’ had dark grey pilei and grows well under spring and autumn conditions in Korea. The fruiting bodies of ‘Guseol’ were of an excellent quality in that not only the stipe was thick and long but also the pileus was small and hard. The optimum temperatures for mycelial growth and fruiting body development were 25~30℃ and 10~16℃, respectively. Time period required for the initiation of the first fruiting body was about 3 to 5 days depending on the temperatures. The shape of fruiting body was thin funnel shape. Fruiting body production per box(43x43x12cm) was about 1545±400.9g which was almost 137% quantity compared to that of parental strain 04-154. Relatively low temperature incubation (11℃) resulted in the development of better quality of ‘Guseol’ mushrooms. When two different media including potato dextrose medium and mushroom complete medium were compared, the mycelial growth of this mushroom were much faster in mushroom complete medium. Similar results were observed with other variety ‘#Chunchu2’. Analysis of the genetic characteristics of the new commercial strain ‘Guseol’ showed a major DNA profile as that of the parental 04-154 when primer URP 1, primer URP 2 and primer URP 5 were used, but different to ‘ #Chunchu2’ that was used as a control. This new variety of the dark grey oyster mushroom had smart and high quality image that corresponds well to “health food”. We therefore expect that this new strain will satisfy the consumers demand for variety and excellent mushrooms.

‘Gonji-5ho’, a new variety of oyster mushroom, for the bag culture, was bred by mating two monokaryons isolated from ‘Chiak-3ho’and ‘Suhan-1ho’. In the characteristics of fruit body, pilei were thick and gray and stipes were thick, and long, and soft. It was better in elasticity and cohesivness of tissue compared to Suhan-1ho. Compared to other varieties, it was suitable to grow at higher temperature. The range of optimum temperature for the mycelial growth was around 26~29 and that for the pinheading and growth of fruit body was around 18~20℃. But when it was cultuered in lower than 15℃, growth was not uniform, culture period was longer, and stipes were uneven. In the bag culture, it was required around 18 days in incubation period and 3 days in primordia formation. The fruit body growth was vital and uniform. The yield was 221.4g/1kg bag.

Recently sawdust cultivation of Shiitake mushroom (Lentinula edodes) is increasing. It is important to make mycelia to be brown on the substrate surface. This browned surface in sawdust cultivation plays an important role like as artificial bark of the oak log, which protects the other pests and suppresses water evaporation in the substrate. In order to isolate genes which related to brown color formation, differential display method was used. Two cDNA fragments obtained by DD-PCR were 1.2 and 1.6kb and these were expressed in white colored mycelia from L. edodes, but not brown colored mycelia. Partial sequencing of these cDNA fragments showed that the 1.6kb cDNA had 100% identity with the microsatellites gene from Dugenia polichroa. However, the other 1.2kb cDNA fragment had poly T tail on 3’ region of partial open reading frame on 5’ region. The new primer designed based on the sequence of 1.2kb cDNA was constructed. RT-PCR analysis using the newly designed 0.12kb cDNA specific primer showed that the gene was only expressed in white color mycelia, but not in brown color mycelia. Sequence analysis of 5’ region of this 1.2kb cDNA revealed that this gene contained partial open reading frame consisted of 110 amino acid. Homology search using DNASIS database showed that this gene had high sequence homology of 66.7% in DNA level and 69.2 % in amino acid level with dTDP-glucose 4,6-dehydratases gene from Arabidopsis thaliata. The dTDP-glucose 4,6- dehydratases gene was known to be function to have tolerance with oxidation stress. These results strongly suggest that this gene isolated from white mycelia of L. edodes might have a function of repressor against mycelia browning. Therefore I designated this gene as BCR (Brown Color Repressor) gene.

This study was carried out to investigated optimum mixing ratio of Korean natural Cudrania tricuspidata for production of functional oyster mushroom. Total nitrogen and carbon source of Cudrania tricuspidata was 0.27% and 40.9%, respectively and C/N ratio was 152. Total nitrogen source and pH of substrates mixed with Cudrania tricuspidata were 2.7~2.8 and 4.9~5.1, respectively. The contents of P2O5,, CaO, MgO and Na2O were no significant difference. Mycerial growth was faster at Cudrania tricuspidata 10% than that of control, but the other treatment was slower. Yields of fruiting body was the highest at Cudrania tricuspidata 20%, and diameter and thick of pileus were no significant difference to increase of Cudrania tricuspidata addition ratio. The L value of pileus was the highest at the Cudrania tricuspidata 20% during mushroom harvest, but there was no significant difference in the a-value and the b-value. Chemical contents of fruiting body were the highest at the Cudrania tricuspidata 30%.

This study was carried out to determine the supplemental level of spent mushroom (Flammulina velutipes) substrates as an energy source in manufacturing of high moisture sorghum whole crop silage. Whole crop sorghum was harvested at heading stage and ensiled with spent mushroom substrates of 20% (S-20), 40% (S-40) and 60% (S-60) as fresh matter basis. Each silage was manufactured in plastic buckets included vinyl bag by three replications and stored for 0, 3, 6 and 9 weeks, respectively. Fermentation characteristics and quality of sorghum silages manufactured by supplemental level of spent mushroom substrates were as follows. Moisture contents of whole crop sorghum and spent mushroom substrates were 83.85% and 54.3%, respectively, and that of silages was 78% for S-20, 71% for S-40 and 68% for S-60. Ether extracts content of silages was significantly (P<0.05) increased during the fermentation periods. The pH in silages fermented for 3 weeks and above ranged from 4.24 to 4.42, and the decrease of pH by fermentation was relatively greater in S-40 compare to the other treatments. The lactic acid content of silage inclined that the S-40 was higher compared to the other treatments and decreased with elongation of fermentation period of silage. The contents of acetic acid and propionic acid of silages were not influenced by treatments and fermentation period. Flieg’s score for estimation of silage quality ranged from 60 to 83, and was relatively high quality in the S-40 fermented for 9 week, and was relatively low quality in the S-60 fermented for 9 week. From above results, we suggest that 40% supplementation of spent Flammulina velutipes mushroom substrates as an energy source is resonable level in manufacturing of high moisture sorghum whole crop silage.

Armillaria spp are well known as a symbiotic fungus with Gastrodia elata. This study was carried out to identify and analyze the genetic relationships among 83 strains of Armillaria spp.. The amplified internal transcribed spacer(ITS) region of the rDNA was about 500~750 bp long and identified by 9 strains; A. mellea, A. tabescens, A. ostoyae, A. gallica, A. novae-zenlandia, A. cepistipes, A. nabsnona, A. gemina, A. sinapina. Sequence analysis showed that 52% of strains were different with original identification. A. gallica, A. cepistipes and A. gemina were so close phylogenetic relationship, that was difficult to classify using ITS region. In A. gallica, 12 strains including ASI10104 were showed a close phylogenetic relationship with A. gallica, A. cepistipes and A. gemina. ASI10017 and ASI10114 were classified as the A. sinapina group, ASI10045 was the A. borealis group, ASI10002 and ASI10025 were the A. ostoyae group. So more studies need for more accurate identification and determine the phylogenetic relationships of Armillaria spp.