Chang-Duck Koo

Whole genome de novo sequencing and genome annotation of the world popular cultivated edible mushroom, Lentinula edodes.

Lentinula edodes, the popular shiitake mushroom, is one of the most important cultivated edible mushrooms. It is used as a food and for medicinal purposes. Here, we present the 46.1 Mb draft genome of L. edodes, comprising 13,028 predicted gene models. The genome assembly consists of 31 scaffolds. Gene annotation provides key information about various signaling pathways and secondary metabolites. This genomic information should help establish the molecular genetic markers for MAS/MAB and increase our understanding of the genome structure and function.

Characteristic of Orchid Mycorrhizal Fungi from Roots of Cypripedium japonicum and C. macranthum

Department of Forestry, Chungbuk National University, Chengju 361-763, Korea(Received June 17, 2010. Accepted June 21, 2010)ABSTRACT: Orchid mycorrhizal fungi(OMF) were examined in roots of the two threatened orchid species, Cyp-ripedium japonicum and C. macranthum. The morphological characteristics of mycorrhizal colonization in the rootsof two orchid species were observed. OMF colonized in the roots of two species were identified using molecular analysis.DNA from the root was extracted and amplified internal transcribed spacer(ITS) region using basidiomycete ITSprimers, ITS1-OF and ITS4-OF. Four species belonging to Tulasnellaceae in roots of C. japonicum and two speciesof Tulasnellaceae and one basidiomycetous species was found in roots of C. macranthum.KEYWORDS : Cypripedium japonicum, Cypripedium macranthum, OMF, Orchid mycorrhizal fungi, Peloton, Tulasnellaceae

Effects of Aeration of Sawdust Cultivation Bags on Hyphal Growth of Lentinula edodes

The effects of aeration through lid filters on the hyphal growth of Lentinula edodes (oak mushroom) in sawdust cultivation bags were investigated. The aeration treatment levels were traditional 27 mm hole cotton plugs, cotton balls and combinations of seven hole sizes × two hole positions (up and under) in the lids covering plastic bags containing 1.4 kg sawdust medium at 63% moisture that had been autoclaved for one hour and inoculated with sawdust spawn of L. edodes strain 921. Aeration treatment effects were measured based on the CO2 concentration at the 15th wk, as well as the hyphal growth rate and degree of weight loss of bags every 14 days for 15 wk. In bags with traditional cotton plugs, the CO2 concentration was 3.8 ± 1.3%, daily mean hyphal growth was 2.3 ± 0.6 mm and daily mean weight loss was 0.84 ± 0.26 g. In the bags with 15 mm diameter holes, the CO2 concentration was 6.0 ± 1.6%, daily hyphal growth was 2.8 ± 0.2 mm and daily weight loss was 0.86 ± 0.4 g. The bags with 15 mm holes had a higher CO2 concentration and lower water loss than bags with other hole sizes, but the hyphal growth was not significantly different from that of other bags. The weight loss of bags increased proportionally relative to the lid hole sizes. Taken together, these results indicate that traditional cotton plugs are economically efficient, but 15 mm hole lids are the most efficient at maintaining hyphal growth and controlling water loss while allowing CO2 emissions.

Changes of Nutrients in Media and Mycelia on Liquid Spawn Culture of Lentinula edodes

Jeonbuk National University, Iksan Campus, Bio Food Technology Ma-dong, Iksan 570-752, KoreaABSTRACT: Lentinula edodes liquid spawn growth under explosive aeration (supplying air with tiny bubbles) and soybean mealaddition to liquid culture medium were investigated in terms of mycelial growth and residual free sugar content. The twotreatments were effective for homogeneous culturing of mycelial spawn and for separating colonies during multiplication after anexponential growth period without limiting sustaining nitrogen nutrients. The mycelial growth and carbon dioxide concentrationwere greatest on the 13th day since the inoculation. At 12th day, however, free sugars were almost depleted in the upper part ofthe liquid medium. Total nitrogen content within precipitated mycelia was the highest at the 13th day. Chitin and sucrose contentsin the mycelia were the highest at the 18th day, but ergosterol content became highest at 22 days. These results suggest thatLentinula edodes liquid spawn is ready in 18 days after inoculation.KEYWORDS :

Development of 44 Novel Polymorphic SSR Markers for Determination of Shiitake Mushroom (Lentinula edodes) Cultivars

The shiitake mushroom (Lentinula edodes) is one of the most popular edible mushrooms in the world and has attracted attention for its value in medicinal and pharmacological uses. With recent advanced research and techniques, the agricultural cultivation of the shiitake mushroom has been greatly increased, especially in East Asia. Additionally, demand for the development of new cultivars with good agricultural traits has been greatly enhanced, but the development processes are complicated and more challenging than for other edible mushrooms. In this study, we developed 44 novel polymorphic simple sequence repeat (SSR) markers for the determination of shiitake mushroom cultivars based on a whole genome sequencing database of L. edodes. These markers were found to be polymorphic and reliable when screened in 23 shiitake mushroom cultivars. For the 44 SSR markers developed in this study, the major allele frequency ranged from 0.13 to 0.94; the number of genotypes and number of alleles were each 2–11; the observed and expected heterozygosity were 0.00–1.00 and 0.10–0.90, respectively; and the polymorphic information content value ranged from 0.10 to 0.89. These new markers can be used for molecular breeding, the determination of cultivars, and other applications.

Cultural Characteristics of New Cultivar of Lentinula edodes, Poongnyunko

In this study, a new cultivar of Lentinula edodes was bred from dikaryotic KFRI 490 and monokaryotic KFRI 536 by Di-mon method. The new breed was named “Poongnyunko” and physiological characteristics was investigated. Its optimal growing temperature was 25oC, and it had thin density. Its colony was colorless and did not form any epithelium. On the 7th day of mycelial growth, “Poongnyunko” was 56.6 mm, and showed higher cellulase activity compared with “Sanlim 4-ho”(52.9 mm). On the 5th day of mycelial growth, “Poongnyunko” was 58.0 mm, and showed higher laccase activity compared with “Sanlim 4ho” (55.6 mm). Its pH at a substrate was 6.0. Before cultivation, the pH of sawdust substrate was 4.7-5.5 went down to 3.7-3.9 after 120-day cultivation. After 60 days of cultivation, the change of CO 2 was the greatest. During the cultivation, CO 2 concentration in a growing bag was 4.67% to 3.90%.

Genetic Relationship of Pleurotus ferulae Strains

This study was carried out to investigate the genetic relationship of Pleurotus ferulae, an edible mushroom found on a medicinal plant, Ferula assa-foetida, in central China. The genetic relationships of 15 Pleurotus species strains, including five P. ferulae strains were analyzed. The strains were divided into seven groups at 80% genetic similarity level according to random amplified polymorphic DNA (RAPD) analysis. Four out of the seven groups consisted of two to four strains, while the other three groups consisted of three strains. In each of the three groups, the three strains were from each of three different Pleurotus species (P. cornucopiae, P. florida and P. sajorcaju). Other strains grouped together for genetic similarity were P. eryngii 26060 and P. fuscus var. ferulae 26065, three strains of P. ostreatus, and four P. ferulae strains (Bakdal, Awi, Cheonsan 1, and Yesan). However, Japanese Seolyi which belongs to P. ferulae and Heukpyung which belongs to P. ostreatus were together in a separate group.

Ergosterol and Water Changes in Tricholoma matsutake Soil Colony during the Mushroom Fruiting Season

Abstract The purpose of this study is to understand spatio-temporal changes of active fungal biomass and water in Tricholoma matsutake soil colonies during the mushroom fruiting season. The active fungal biomass was estimated by analyzing ergosterol content at four different points within four replicated locations in a single circular T. matsutake colony at Ssanggok valleyin the Sogri Mt. National Park in Korea during 2003 to 2005. The four points were the ahead of the colony, the front edge of the colony and 20 cm and 40 cm back from the front edge of the colony. Ergosterol content was 0.0 to 0.7 μg per gram dried soil at the ahead, 2.5 to 4.8 μg at the front edge, 0.5 to 1.8 μg at the 20 cm back and 0.3 to 0.8 pg at the 40 cm back. The ergosterol content was very high at the front edge where the 7. matsutake hyphae were most active. However, ergosterol content did not significantly change during the fruiting season, September to October. Soil water contents were lower at the front edge and 20 cm back from the front edge of the colony than at the ahead and 40 cm back during the fruiting season. Soil water content ranged from 12 to 19% at the ahead, 10 to 11% at the edge, 9 to 11% at the 20 cm back and 11 to 15% at the 40 cm back. Our results suggest that the active front edge of the T. matsutake soil colony could be managed in terms of water relation and T. matsutake eetomyeorrhizal root development.

Characteristics of Pinewood Nematode Trapping by Nematophagous Arthrobotrys spp.

Pinewood nematode (PWN) trapping by nematophagous fungi, Arthrobotrys conoides, A. dactyloides and A. oligospora and the fungal growth were characterized. The three Arthrobotrys species each was inoculated into the PWN cultured on Botrytis cinera fungal colony on potato dextrose agar (PDA). The effects of temperature, pH, PWN inoculation density and nutrients on the growth of the three Arthrobotrys spp were measured. A. conoides grew fast, 13.9 mm/day while A. dactyloides grew slow, 3 mm/day. PDA medium was the best for the fungal growth at and pH 4.5. The Arthrobotrys spp growth was stimulated by 500 nematodes inoculation but not by 1000 inoculation. A. dactyloides did not grow below pH 4.5 and at high PWN density. A. conoides and A oligospora formed trapping organs with thick constricting hyphal network only when PWN present, while A. dactyloides formed the organ with circular hyphae constitutively. A. conoides formed trapping organs faster than A. oligospora did. The nematode trapping hyphae of the fungi penetrated into PNW inside to form many tiny infection bulbs and to digest the nematode. However, A. dactyloides formed a few trapping organs but no trapping was observed. Infection rate of PWN was 95% by A. conoides, 80% by A. oligospora and 92% by the combination inoculation of A. conoides and A. oligospora. In contrast A. dactyloides increased PWN density without infecton. There was no interaction effect in any combination inoculation of the three Arthrobotrys spp. A. conoides enhanced PWN infection rate by rapid hyphal growth and early trapping, while A. oligospora did it by increasing hyphal density. In conclusion A. conoides is the most effective in both hyphal growth and infection, and thus these characteristics can be utilized as a biological control of PWN.

Changes of nutrient contents in the log of Quercus acutissima by cutting period for Lentinula edodes log cultivation

ABSTRACT This study is to find out an appropriate log cutting period for saprotropic Lentinula edodes log cultivation. Seasonal changes in nutrients in sapwood and cell activities in the inner bark from logs of Quercus acutissima cut during September to February were analyzed. Total carbon content in the sapwood was higher in September (76.5%) than in other months (67.8–69.2%). Total nitrogen content was higher in November and December (0.21–0.22%) than in other months (0.14–0.15%). Inorganic nutrients such as phosphate, potassium and magnesium, and heavy metals like cadmium were higher in November and December than in other months. Over 90% of axially vertical and radial parenchymatous cells contained starch granules in November and December while only 20–30% of these cells did in February. The cell activities in the inner bark of logs cut in October to November, measured with formazan absorbance values during mid March, were 0.013–0.018, which were lower than those cut in December (0.027–0.045). Therefore, our results support that it is better to cut logs for L. edodes cultivation in November when nutrients accumulate in the wood but wood cells are less active.