벼멸구에 강한 병원성이 있는 Serratia marcescens, biotype A2a를 분리, 동정하였다. 벼 유묘에 분무한 후 성충-계절풍을 따라 비래하는 형태-을 공시하고 병원성을 조사하여 3~5일 만에 강한 살충력을 발견하였다. 따라서, 본 세균의 곤충병원성 관련 형질 탐색을 하기 위하여 Tn5로써 돌연변이를 시도한 후, Chitinase, Protease, DNase indicator media에서 돌연변이 계통을 분리하였다. 이들을 공시충에 병원성을 검정한 결과 Pro-Strain중에서 병원력이 현저히 떨어지는 현상을 관찰하였다. 공시충을 전자현미경(SEM, TEM)으로 관찰하여, abdomen의 전장부위와 표피사이에 다수의 세균이 증식하였음을 발견하였다. 곤충복부표피조직 중 cuticle층은 intact한 상태였다. 따라서, 이에 관련된 유전자를 분리하기 위해 genomic library 실험을 진행하고 있다.

Background : Ginseng (Panax ginseng C.A. Meyer) is one of the most important medicinal plants in Korea, but its yields are often reduced by a variety of root pathogens. The root rot of ginseng is a destructive soil-borne disease caused by Cylindrocarpon destructans (teleomorph: Ilyonectria radicicola). Methods and Results : Ilyonectria radicicola and its Cylindrocarpon-like anamorph represent a species complex that is commonly associated with root rot disease symptoms on virulence. During the course of this study, several species could be distinguished from I. radicicola sensu stricto based on morphological and culture characteristics. As results of investigated culture characteristics, optimal temperature for mycelial growth of isolates were 20℃, and colony pattern and color were slightly different on PDA. Isolates of I. radicicola were analyzed for their genetic relatedness based on several genes and microsatellite region. I. radicicola group was divided into two small groups. Conclusion : Therefore, we were able to confirm pathogenicity and genetic difference between the isolates in each of the groups of the pathogen. Among these isolates, 21.5% were classified as highly virulent and 78.5% were weakly virulent. *(Corresponding

Background : The fungus Cylindrocarpon destructans (Zins) Scholten is the cause of root rot in many ginseng production areas. Root exudate composition and quantity vary in relation to plant nutritional status, but the impact of the differences on rhizosphere microbial communities is not known. Methods and Results : Five kinds of rotation crops, sudan grass soybean peanut sweet potato, perilla were grown for one year in ginseng garden harvested 6-year-old ginseng. The ratio of gram-negative bacteria, fungi, bacteria, total microbial biomass, aerobic/anaerobic microbes were increased by rotational crop cultivation, while the ratio of actinomycetes and the ratio of saturated to unsaturated fatty acids were decreased. The increase in the fungal density or the increase in the proportion of fungi to the bacteria tended to increase the incidence of root rot, but there was no significant difference. The yield of ginseng root showed a highly significant negative correlation with actinomycetes. The correlation between the soil chemical properties and the incidence of root rot was analyzed by cultivating 23 kinds of green manure crops for one year in field where cultivated ginseng continuously. The survival rate of ginseng showed a highly significant positive correlation with soil acidity and a highly significant negative correlation with nitrate nitrogen, and a significant negative correlation with soil salt concentration. Conclusion : Rotation crops improved soil microbial communities, lowered the rate of fungi and increased the proportion of bacteria, the survival rate of ginseng was significantly correlated with soil acidity, nitrate nitrogen and soil salinity.

Background: Some plants have harmful effects on fungi and bacteria as well as plants. Incorporating into soil as green manures are effective in reducing population densities of soil pathogens. Methods and Results: Twenty-three species of green manure crops were cultivated after the harvest of 6-year-old ginseng and then incorporated green manure into the soil at the flowering stage. The following year, the root rot ratio of 2-year-old ginseng and soil chemical properties were investigated. Sorghum sudanense, Helianthus annuus, and Helianthus tuberosus were relatively high in dry matter production. Without incorporating green manure into soil, NO3, EC (electric conductivity) and K were decreased by 95%, 79% and 65%, respectively. When green manure was incorporated to soil, P2O5 and NO3, were reduced by 41% and 25%, respectively. The survived root ratio of 2-year-old ginseng were significantly increased by 56.2%, 47.5%, and 47.3% in Sorghum sudanense, Ricinus communis and Helianthus tuberosus, respectively, In addition, there was a significant increase in Secale cereale, Chrysanthemum morifolium, Atractylodes macrocephala, and Smallanthus sonchifolius. The survived root ratio of ginseng showed a significant positive correlation with soil pH and a negative correlation with NO3, and EC. Conclusion: Cultivation of Chrysanthemum family mainly using rhizome and root as green manure was effective for root rot disease of ginseng.

Panax ginseng C.A. meyer (family: Araliaceae) is a perennial crop that has been widely used as a traditional medicine in Korea. Various P. ginseng cultivars exhibit a range of morphological and physiological traits as well as genetic diversity. To elucidate the differences of primary metabolism underlying such genetic diverstiy, we performed primary metabolite profiles in adventitious roots from five Panax ginseng cultivars using gas chromatography-mass spectrometry (GC-MS). The GC-MS analysis revealed eight primary metabolites as biomarkers and allowed us to classify the five cultivars into three groups. We selected three cultivars to represent each group and analyzed their transcriptomes by Illumina sequencing. We inspected 100 unigenes involved in seven primary metabolite biosynthesis pathways and found that 21 unigenes encoding 15 enzymes were differentially expressed among the three cultivars. Integrated analysis of transcriptomes and metabolomes revealed that the ginseng cultivars differ in primary metabolites as well as in the putative genes involved in the complex process of primary metabolic pathways. Our data derived from this integrated analysis provide insights into the underlying complexity of genes and metabolites that co-regulate flux through these pathways in ginseng.

This study was carried out to investigate the difference of growth characteristics, yield and extract content between upland and paddy ginseng cultured with 4­year-old ginseng in 2003. Although upland ginseng showed larger variation in yield than that of paddy ginseng, the average of it was greater than that of paddy ginseng because it showed better growth of aerial part and higher survival rate than that of paddy ginseng. Moisture content of fresh root was 71.8~%~;(68.5~~73.1~%),~;and~;72.7~%~;(70.2 ~~74.9~%) on average in upland and paddy ginseng, respectively. Paddy ginseng showed higher hardness in taproot, and higher rate of rusty colored root than that of upland ginseng. The ratio of taproot dry weight in upland ginseng was smaller than that of paddy ginseng, while that of lateral root was larger in upland ginseng. Ratio of marketable root (>60g) to total harvested roots was 13.7~%~;(0.82~~8.0~%)~;and~;7.7~%~;(1.6~~12.6~%) in upland and paddy ginseng, respectively. Extract content did not show distinct difference between upland and paddy ginseng, but it showed large variation from 16.1~;to~;25.1~% in taproot, and from 24.2~;to~;32.5~% in lateral root depanding on the ginseng field examined.

Shinnamjag is a round, smooth, white-skinned, and fleshed potato cultivar with erect plant shape and early maturity. It has excellent table quality. Its yields are high, especially with prominent marketable yield compared to Superior, a leading potato cul

‘Jowon’ is a new early-maturing potato variety for table use. It has spreading growth habit with narrow oval leaves. Its tubers are attractively round with white skin and light yellow flesh color. The yielding ability of Jowon is similar to Superior. Jowo