• Research in Plant Disease
• /
• v.23 no.4
• /
• pp.322-333
• /
• 2017

In June and July 2015 and 2017, typical signs and symptoms of brown rot were observed on the fruit of Japanese apricot, peach, apricot, Japanese plum, and sweet cherry with incidence levels of 2-5% in Jeonju and Imsil, Korea. Early symptoms were small, circular, light brown spots that eventually destroyed entire fruit. Small sporodochia later appeared on the surface. Conidia isolated from each host were one-celled, hyaline, lemon-shaped and borne in branched monilioid chains. The optimal temperature range for hyphal growth of all the isolates was $20-25^{\circ}C$. The growth of hyphae was faster on potato dextrose agar and oatmeal agar than others. Multiple alignments using the ITS sequences from different host showed that they matched each other (100%). The ITS sequences showed 100% identity to those of M. fructicola. Based on the morphological characteristics and phylogenetic analysis via internal transcribed spacer (ITS), all the isolate was identified as M. fructicola. Pathogenicity of representative isolates was proved by artificial inoculation, fulfilling Koch's postulates. This is the first confirmed report on brown rot caused by M. fructicola on stone fruit in Korea.

• Research in Plant Disease
• /
• v.23 no.4
• /
• pp.367-371
• /
• 2017

In 2015, symptoms of die-back on Rosa hybrida were observed in Taean, Korea. The aims of this study were to determine the cause of die-back on Rosa hybrida and characterize the pathogen. The fungal isolates were obtained and used for pathogenicity test, morphological and molecular analyses. The pathogenicity test on healthy branches of Rosa hybrida produced die-back, as the original symptoms. For the morphological study, the isolates were inoculated onto potato dextrose agar and incubated for 7 days at $25^{\circ}C$. The colonies grew up quickly and turned white to gray in color. Conidia were observed under an optical microscope. The features of conidia were ellipsoidal, grayish brown in color, $20-31{\times}11-17{\mu}m$ in size and had one septum. Molecular analyses of the ITS region, TEF and TUB genes were conducted to confirm the identity of the pathogen. The phylogenetic tree of the multi-gene sequences indicated that the causal agent was Lasiodiplodia pseudotheobromae. This study is the first report of die-back caused by Lasiodiplodia pseudotheobromae on Rose (Rosa hybrida).

• The Korean Journal of Mycology
• /
• v.9 no.4
• /
• pp.169-176
• /
• 1981

Survey of sesame crop in the cultivators' field in the district of Daejeon, Yuseong, Sintanjin, Nonsan and Keumsan revealed that Alternaria and Corynespora blights of sesame were wide spread and caused severe damage to sesame plants. Symptoms of a new disease of sesame in Korea caused by Alternaria sesami were spreading, dark-brown to black, water-soaked lesions which often could be traced the entire length of the stem. In severe infections, several lesions coalesced together involving a major portion of the blade and the infected leaves dried and usually dropped off. Symptoms of Corynespora blight, caused by Corynespora cassiicola, were irregular shaped, concentrically-zoned, light brown to reddish brown lesions which later coalesced and caused defoliation. Stem lesions were long, reddish brown streaks that often coalesced, blighting the plants. The optimum temperatures for mycelial growth of A. sesami and C. cassiicola were about $27^{\circ}C$ and sporulations of these 2 fungi were stimulated under alternating light and darkness. Mycelial growth and sporulation of A. sesami and C. cassiicola were the greatest on sesame oatmeal agar (SOA) and potato dextrose agar (PDA), respectively.

• Research in Plant Disease
• /
• v.21 no.1
• /
• pp.27-31
• /
• 2015

In April 2014, Fusarium wilt was found on kohlrabi seedlings in Iksan, Korea. Symptoms included wilting of foliage, drying and withering of older leaves, and stunting of the plants. The infected plants eventually died during growth. Colonies on potato dextrose agar were pinkish white, and felted with cottony and aerial mycelium. Macroconidia were falcate to almost straight, thin walled and usually 3-septate. Microconidia were usually formed abundantly in false-heads on short monophialides on the hyphae and were hyaline, smooth, oval to ellipsoidal, aseptate or medianly 1-septate, very occasionally 2-septate, slightly constricted at the septa, $4-11{\times}2.5-5{\mu}m$. On the basis of the morphological characteristics and phylogenetic analyses of molecular markers (internal transcribed spacer rDNA and translation elongation factor $1{\alpha}$), the fungus was identified as Fusarium oxysporum. Pathogenicity of a representative isolate was proved by artificial inoculation, fulfilling Koch's postulates. To our knowledge, this is the first report on the occurrence of Fusarium oxysporum on kohlrabi in Korea.

• Research in Plant Disease
• /
• v.21 no.1
• /
• pp.36-39
• /
• 2015

In June 2012 and 2013, a destructive stem rot symptoms of Ligularia fischeri occurred sporadically in Hoengseong-gun and Pyeongchang-gun Gangwon-do, Korea. The typical symptom included water-soaking on the main stem, rotting, wilting and blighting, which eventually leads to death of the plant. White mycelial mats were spread over lesions and brown sclerotia were formed on stems and near soil surface. The sclerotia were white to brown, spherical or irregular, 1-3 mm in size on potato dextrose agar (PDA), The optimum temperature range of hyphal growth was $25-30^{\circ}C$ and the hyphal diameter was $4-10{\mu}m$. The typical clamp connections were observed in the hyphae of the fungus grown on PDA. The resulting sequence of 695 bp was deposited in GenBank. A BLAST search revealed that sequences of the this isolates showed >99% identity with those of Sclerotium rolfsii. On the basis of the morphological characteristics and phylogenetic analyses of molecular markers ITS rDNA, the fungi were identified as S. rolfsii. A pathogenicity test was carried out to fulfill Koch's postulates. To our knowledge, this is the first report of S. rolfsii on Ligularia fischeri in Korea.

• Journal of Dairy Science and Biotechnology
• /
• v.37 no.3
• /
• pp.196-205
• /
• 2019

Helianthus tuberosus is a perennial plant in the genus, Asteraceae. Pork potato has various pharmacological functions such as improving constipation, preventing bowel disease, inhibiting colon cancer, reducing serum cholesterol, lowering blood lipids, and enhancing blood sugar. This study investigated the physicochemical properties of fermented milk by adding Helianthus tuberosus powder. During the fermentation process, the pH of the fermented milk with added Helianthus tuberosus was higher after 16 hours of fermentation. At 48 hours of fermentation, the pH decreased to 3.70, 3.65, 3.63, and 3.59 with 0% (the control group), 1%, 3%, and 5% Helianthus tuberosus added, respectively. In the last 48 hours of fermentation, the acidity increased to 2.35%, 2.57%, and 3.17% with 0% (the control group), 1%, 3%, and 5% Helianthus tuberosus added, respectively. The number of lactic acid bacteria increased as the quantity of Helianthus tuberosus added increased. The highest number of lactic acid bacteria was 9.96 log CFU/g after 16 hours of fermentation with a 5% addition of Helianthus tuberosus . After 48 hours of fermentation, the amount of lactic acid bacteria decreased to 7.84 log CFU/g and 7.88 log CFU/g in the control group and the 1% added Helianthus tuberosus group, respectively. The addition of 3% and 5% Helianthus tuberosus increased the lactic acid bacteria count to 9.48 log CFU/ g and 9.81 log CFU/g, respectively. As the fermentation time increased, oxalic acid and tartaric acid decreased but lactic acid increased. Lactose degraded galactose and glucose over time. After 48 hours of fermentation, the viscosity in the control, 1%, 3%, 5% added Helianthus tuberosus groups increased to 1,006 cP, 1,026 cP, 1,040 cP, and 1,106 cP, respectively. The antioxidant effect was higher in the 5% added Helianthus tuberosus group (84.14%) than in the control group (80.39%) at 48 hours of fermentation. The concentration of polyphenol was 1.6 mg/g and antimicrobial activity was strong against E. coli and Staphylococcus aureus.

• Journal of Nutrition and Health
• /
• v.46 no.1
• /
• pp.15-25
• /
• 2013

The purpose of this study is to investigate the proportion and associated risk factors of hypertriglyceridemia in rural Vietnamese women. Research data were collected as part of the Korean Genome and Epidemiology Study (KoGES). A cross-sectional study of 957 Vietnamese women in their 20 to 30s was conducted in rural areas of Bavi, Vietnam. Subjects were classified as hypertriglyceridemic (serum TG ${\geq}$ 150 mg/dL). Demographic, socio-economic details, anthro-pometric measurements, and blood profiles were recorded. The proportion of hypertriglyceridemic subjects was 22.0%, and the mean age of hypertriglyceridemics subjects was older than that of normo-triglyceridemic subjects (p < 0.05). In hypertriglyceridemic subjects, height, HDL-cholesterol, and LDL-cholesterol were significantly lower, compared to subjects with normo-triglyceridemia, while weight, body mass index, waist hip ratio, body fat %, blood pressure, fasting blood sugar, total cholesterol, and atherogenic index were higher, compared to those with normo-triglyceridemia. Intake of cereal and cereal products, total plant food, and cereal/potato fiber in subjects with hypertriglyceridemia was significantly higher, compared to normo-triglyceridemic subjects. Hypertriglyceridemic subjects had a significantly lower intake of animal calcium and retinol than normo-triglyceridemic subjects. Significant positive relationships were observed between the prevalence of hypertriglyceridemia and consumption of total plant food [OR (95% CI) for the highest tertile, compared to the lowest: 1.764 (1.131-2.750); p for trend = 0.008] and crude fiber [OR (95% CI) for the highest tertile compared to the lowest: 1.651 (1.092-2.497); p for trend = 0.027]. In addition, a significant inverse relationship was observed between the prevalence of hypertriglyceridemia and cholesterol intake [OR (95% CI) for the highest tertile, compared to the lowest: 0.601 (0.400-0.901); p for trend = 0.012]. These findings may provide basic data for use by policymakers and dieticians in future development of nutrition and health programs to encourage healthier eating habits, and to prevent hypertriglyceridemia advancing cardiovascular disease in rural Vietnamese women.

• Research in Plant Disease
• /
• v.13 no.3
• /
• pp.211-215
• /
• 2007

Since 2003, anthracnose symptoms on Eucalyptus globulus were observed in farmer's field at Jisepo, Ilwoon-myon, Geoje city, Gyeongnam province, Korea. Typical symptoms of dark brown to black spot appeared on the leaves, twigs, and stems. Infected young trees were wilted, blighted and died eventually. The pathogen isolated from the typical symptom formed gray to dark gray colony on potato dextrose agar and showed optimum growth at $30^{\circ}C$. Conidia were single celled, colorless, cylindrical with obtuse ends, and $9{\sim}22{\times}3{\sim}6{\mu}m$ in size. Appressoria were dark brown, ovate to obovate, and $6{\sim}18{\times}4{\sim}10{\mu}m$ in size. Perithecia were black and globose in shape and $76{\times}274{\mu}m$ in size. Asci were clavate to cylindrical in shape and $42{\sim}76{\times}8{\sim}12{\mu}m$ in size. Ascospores were cylindrical, fusiform, slightly curved at the center, and $10{\sim}23{\times}4{\sim}6{\mu}m$ in size. On the basis of mycological characteristics and pathogenicity test on E. globulus, the pathogen was identified as Glomerella cingulata. This is the first report of the anthracnose on E, globulus caused by G. cingulata in Korea.

• Research in Plant Disease
• /
• v.22 no.1
• /
• pp.50-54
• /
• 2016

In early June 2014, leaf spot symptoms were observed on black chokeberry (Aronia melanocarpa) in Yesan-gun and Geumsan-gun, Chungcheongnam-do in Korea. The initial symptoms on leave surfaces were brown small-circular spots with a yellow halo lesion, and gradually the small spots were fused, all of infected leaves dropped eventually. A fungus were isolated from the initial lesion, and cultured on potato dextrose agar. Colony color on upper surface of plate varied from olive gray to charcoal gray. Size of conidia mostly extend to $19-50{\times}5-9{\mu}m$ in nature and $20-59{\times}8-13{\mu}m$ in culture, with 3-8 transverse septa and usually no longitudinal septum or only 1 longitudinal septum in 1-3 of the transverse compartments, and also have a short or long beak. Pathogenicity was investigated using wounded or unwounded black chokeberry and apple leaves. After 7 days of inoculation, leaf spots were similar to the symptoms naturally occurred in the field. On the basis of mycological characteristics, pathogenicity, and ITS rDNA sequence analysis, this fungus was identified as Alternaria mali. This is the first report of Alternaria leaf spot on black chokeberry caused by A. mali in Korea.

• Research in Plant Disease
• /
• v.22 no.4
• /
• pp.293-296
• /
• 2016

In late June 2016, stalk rot symptoms were observed on five vatieties of sorghum (Sorghum bicolar) at organic paddy-upland rotation system in Anseong city, Korea. The initial symptom on stalk surfaces was red color with a dark red spot lesion. A fungus was isolated from the initial lesion, and cultured on potato dextrose agar. Size of microconidia mostly extend to $5-19{\times}2-{\mu}m$ in culture, with 0-1 septa and macroconidia extend to $29-52{\times}3-4{\mu}m$ with 4-6 septa. Pathogenicity was investigated using conidial suspension spray to seedling of sorghum. After 3 days of inoculation, the dark red lesion was produced on stalks. On the basis of mycological characteristics, pathogenicity, and internal transcribed spacer (ITS) rDNA sequence analysis, this fungus was identified as Fusarium thapsinum. This is the first report of stalk rot on sorghum caused by F. thapsinum in Korea.