• The Plant Pathology Journal
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• v.31 no.3
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• pp.203-211
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• 2015

Maize is the dominant cereal crop produced in the US. One of the main fungal pathogens of maize is Fusarium verticillioides, the causative agent of ear and stalk rots. Significantly, the fungus produces a group of mycotoxins - fumonisins - on infested kernels, which have been linked to various illnesses in humans and animals. Nonetheless, durable resistance against F. verticillioides in maize is not currently available. In Texas, over 2.1 million acres of maize are vulnerable to fumonisin contamination, but understanding of the distribution of toxigenic F. verticillioides in maize-producing areas is currently lacking. Our goal was to investigate the genetic variability of F. verticillioides in Texas with an emphasis on fumonisin trait and geographical distribution. A total of 164 F. verticillioides cultures were isolated from 65 maize-producing counties. DNA from each isolate was extracted and analyzed by PCR for the presence of FUM1- a key fumonisin biosynthesis gene - and mating type genes. Results showed that all isolates are in fact F. verticillioides capable of producing fumonisins with a 1:1 mating-type gene ratio in the population. To further study the genetic diversity of the population, isolates were analyzed using RAPD fingerprinting. Polymorphic markers were identified and the analysis showed no clear correlation between the RAPD profile of the isolates and their corresponding geographical origin. Our data suggest the toxigenic F. verticillioides population in Texas is widely distributed wherever maize is grown. We also hypothesize that the population is fluid, with active movement and genetic recombination occurring in the field.

• The Plant Pathology Journal
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• v.28 no.4
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• pp.357-363
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• 2012

Several species belonging to the Gibberella fujikuroi species (Gf ) complex are commonly associated with rice and corn, not only causing serious diseases, but also producing fumonisins, a group of mycotoxins harmful to animals and humans. To characterize the population structure of the putative fumonisin-producing Gf complex in Korea, we obtained 276 candidate isolates from rice and corn harvested in 2009 and 2010 by diagnostic polymerase chain reaction with several specific primer sets. Phylogenetic trees were constructed using multilocus sequences (combined RPB2 and EF1A, totaling 1.6 kb) from these isolates. Among the 135 isolates from rice, F. fujikuroi (teleomorph: G. fujikuroi; 59.3%) and F. proliferatum (G. intermedia; 13.3%) were predominant, followed by F. concentricum (5.9%). Additionally, twenty-five (18.5%) rice isolates belonged in a distinct subclade of F. commune, a non-member of the Gf complex. In contrast, F. verticillioides was the most predominant species (38.3%) among the 141 corn isolates, and followed by F. fujikuroi (27.7%), F. proliferatum (14.9%), F. subglutinans (7.1%), and F. concentricum (2.8%). A single mating type (MAT1-1) was found predominantly among the Gf complex isolates examined. Possible distinct subclades were detected within the populations of F. fujikuroi and F. proliferatum; however, this needs further confirmation. This is the first reported population-level characterization of putative fumonisin-producing Gf complex associated with rice and corn in Korea.

• Korean Journal of Animal Reproduction
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• v.24 no.2
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• pp.209-216
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• 2000

This study was carried out to investigate the effects of breed, age of boar, season, parity and mating system on boar semen characteristics and fertilizing capacity. A total of 4181 sows and 199 boars of Durocs (D), Landraces (L), and Yorkshires (Y) were used for this experiment at Darby Artificicial Insemination Center from 1996 through 1999. Semen volume per ejaculate was largest in Landrace (266.8 $m\ell$), followed by Yorkshire, and was smallest in Duroc. Sperm motility did not show significant differences among the above breeds. Sperm concentration was lowest in Landrace (4.7$\times$10$^{9}$ sperm/$m\ell$) and was highest in Duroc (5.7$\times$10$^{9}$ sperm/$m\ell$). Semen volume per ejaculate according to the age of boars was largest at the age of 2 years, followed by the age of 4 and 3 years, and was smallest at the age of I year. Semen volume per ejaculate according to the season in boars was largest in winter (228.6 $m\ell$), followed by autumn and summer, and was smallest in spring. Sperm concentration was highest in spring (5.9$\times$10$^{9}$ sperm/$m\ell$), followed by summer and winter, and was lowest in autumn. The average litter weight at birth did not show any differences according to the mating type. But the number of pigs born alive per litter was largest (9.5 pigs) in the natural mating ＋ artificial insemination group, followed by the artificial insemination group (9.2 pigs), and was smallest (8.9 pigs) in the natural mating group (P＜0.01). The average litter weight at birth and number of pigs born alive per litter did not show any differences between the natural mating and artificial insemination. The L (♀)$\times$Y (♂) and L (♀)$\times$L (♂) matings show $\varepsilon$ d higher average litter weight at birth and number of pigs born alive per litter than the Y (♀) $\times$ Y (♂) and Y (♀) $\times$ L (♂) matings. The pigs in the 2~6th parities had higher average litter weight at birth and number of pigs born alive per litter than those in the 1 st and 7~9th parities.

• Research in Plant Disease
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• v.10 no.1
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• pp.17-20
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• 2004

A disease causing blights on leaves, stems, flowers, and pods of Vinca (Catharanthus roseus L.) was occurred in Aug. 2003 in Chengdo Peach Experiment Station. A species of Phytophthora was isolated from the diseased tissues. The causal fungus was identified as Phytophthora nicotianae on the basis of mycological characteristics and pathogenicity. Sporangia were ovoid to spherical, noncaducous, prominently papillate and averaged 38.0${\times}$31.0 ${\mu}{\textrm}{m}$ in dimension. Chlamydospores were abundantly produced on agar media and sized about 30.5 fm in diameter, The fungus was heterothallic and Al mating type. Oospores were measured 23.1 ${\mu}{\textrm}{m}$ in size. Optimum temperature for growth of the fungus was 25 to 3$0^{\circ}C$. This is the first report of occurrence of foliage blight of Vinca caused by P. nicotianae in Korea.

• Korean Journal Plant Pathology
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• v.14 no.5
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• pp.452-457
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• 1998

Thirty-eight isolates of Phytophthora sp. caused rots on roots and basal stems were collected from five flowering plants from 1992 to 1997 at eight cultivation areas in Korea. All the isolates were identified as P. nicotianae based on following characteristics. The fungus produced markedly papillate, not caducous and ovoid to spherical sporangia, abundant chlamydospores, and small oospores with amphigynous antheridia only when paired with either A1 or A2 mating type. All isolates grew well at 35$^{\circ}C$ and showed distinct arachnoid colony patterns on CMA and PDA. Sizes of sporangia and chlamydospores of five representative isolates from each plant averaged 43-52$\times$30-38 ${\mu}{\textrm}{m}$ and 28 ~34 ${\mu}{\textrm}{m}$. Mating type of the isolates was either A1 or A2, and oogonia and oospores were measured as 28~31 ${\mu}{\textrm}{m}$ and 21~25 ${\mu}{\textrm}{m}$. PCR-RFLP analysis of rDNA of the five isolates resulted that restriction band patterns of the small subunit and ITS regions were identical to a perilla isolate of P. nicotianae, but distinct from P. cactorum and P. capsici. Cross inoculation tests showed that the five isolates had pathogenicity to lily, christmas cactus, anthurium, baby's breath and carnation with different degrees. However, each isolate showed stronger pathogenicity to its corresponding original host than others. Among five lily cultivars Georgia and Quririna were more susceptible than Napoli and others. This is first report of Phytophthora root and stem rot of lily, Christmas cactus, anthurium, baby's breath and monochoria in Korea.

• Research in Plant Disease
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• v.13 no.3
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• pp.207-210
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• 2007

A stem and root rot disease of English ivy (Hedera helix) was found in the flower market, Jeonju, Chonbuk province, Korea in May 2007. A Phytophthora species was isolated from the diseased part of the plant. Based on the mycological properties and pathogenesis the isolate was identified as Phytophthora cinnamomi. The fungus produce ovoid sporangium which was ovoid to spherical and obpyriform which is noncaducous, non-papillate and averaged $33.8{\times}16{\mu}m$ in dimension. Chlamydospores were abundantly produced on agar media and sized about $19.7{\mu}m$ in diameter. The fungus was heterothallic and A1 mating type. Oospores were measured $26.2{\mu}m$ in size. Optimum temperature for growth of the fungus was 25 to $30^{\circ}C$. Up to our knowledge, this is the first report demonstrating the stem rot on English ivy caused by P. cinnamomi in Korea.

• Research in Plant Disease
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• v.14 no.2
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• pp.122-126
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• 2008

A stem and leaf rot disease of English ivy(Hedera helix) was found in the flower market, Jeonju, Chonbuk province, Korea in July 2007. A Phytophthora species was isolated from the diseased part of the plant. Based on the mycological properties and pathogenesis the isolate was identified as Phytophthora nicotianae. The fungus produce ovoid sporangium which was ovoid to spherical which is noncaducous, papillate and averaged $35.4{\times}25.2{\mu}m$ in dimension. Chlamydospores were abundantly produced on agar media and sized about 28.5 ${\mu}m$ in diameter. The fungus was heterothallic and A1 mating type. Oospores were measured 23.3 ${\mu}m$ in size. Optimum temperature for growth of the fungus was 25 to $30^{\circ}C$. Up to our knowledge, this is the first report demonstrating the stem rot on English ivy caused by P. nicotianae in Korea.

• The Korean Journal of Mycology
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• v.26 no.1 s.84
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• pp.16-19
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• 1998

A study was carried out to explore the method for the germination of the spore of Ganoderma. Three strains of Ganoderma were examined using 2 different media such as PDA and LBA at three different temperatures. As it has been known the germination rate was very low under all the conditions examined. G. lucidum ASI 7004 showed 0.02% germination on both media at $25^{\circ}C$ and $30^{\circ}C$ respectively. The germination rate of ASI 7091 was 0.05% on PDA medium at $30^{\circ}C$. The germination rate of G. oregonense ASI 7067 was 0.67% on PDA at $35^{\circ}C$. LBA medium was found to be inadequate for the germination of Ganderma species in this study. In a consequent study, four mating types of G. oregonense such as $A_1B_1,\;A_1B_2,\;A_2B_1\;and\;A_2B_2$ were identified.

• The Korean Journal of Mycology
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• v.22 no.2
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• pp.117-121
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• 1994

Five strains of Pleurotus sajor-caju were collected from some countries including India and Papua New Guinea. Four strains produced brown fruitbody but the other strain from Papua New Guinea produced white fruitbody. Monokaryons obtained from both strains producing brown fruitbody and white fruitbody were mated each other. They showed different mating types such as brown strain of $A_1A_2B_1B_2$ and white strain of $A_3A_4B_3B_4$. DNAs were isolated from mycelia of five strains of P. sajor-caju. Mitochondrial DNA was seperated from nuclear DNA by bisbenzimide-CsCl ultracentrifugation. Digestion of the fungal mitochondrial DNA with Eco RI restriction endonuclease yielded from ten to fourteen fragments. Two strains of the five strains showed different restriction pattern of mitochondrial DNA from the other three strains. Summation of the fragment sizes gave a mitochondrial DNA size of about 60 to 65kb.

• Mycobiology
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• v.42 no.1
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• pp.73-78
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• 2014

Cryptococcal infection is primarily caused by two species, Cryptococcus neoformans and C. gattii. Between the two species, C. neoformans var. grubii is the major causative agent of cryptococcosis in Asia. We investigated the molecular characteristics of 46 isolates of C. neoformans from patients with cryptococcosis between 2008 and 2012 in Seoul, Korea. All the isolates were determined to be C. neoformans var. grubii (serotype A), mating type $MAT{\alpha}$, and molecular type VNI by PCR-restriction fragment length polymorphism of the URA5 gene. Multilocus sequencing type (MLST) analysis using the International Society of Human and Animal Mycoses (ISHAM) consensus MLST scheme identified two sequence types (ST). Out of the 46 strains, 44 (95.7%) were identified as ST5, and remaining 2 were identified as ST31. Our study revealed that the clinical strains of C. neoformans in Korea are genetically homogeneous with the VNI/ST5 genotypes, and new appearance of VNI/ST31 genotype may serve as an important indicator of global genetic analysis.