• Korean Journal of Plant Resources
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• v.29 no.6
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• pp.635-641
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• 2016

Sweet potato (Ipomoea batatas L.) shoot tips grown in vitro were successfully cryopreserved by encapsulation-vitrification. Encapsulated explants are very easily manipulated, due to the relatively large size of the alginate beads, and a large number of samples can be treated simultaneously. In this study, the effects of sucrose preculture, cryoprotectant preculture, and post-warm recovery media on regrowth, following liquid nitrogen (LN) exposure, were investigated to establish an efficient encapsulation-vitrification protocol for sweet potato. Shoot tips of plants grown in vitro were precultured in 0.3 M sucrose for 2 d before encapsulation. Encapsulated shoot tips were pre-incubated in liquid MS (Murashige and Skoog) medium containing 0.5 M sucrose for 16 h, before preculturing in sucrose-enriched medium (0.7 M sucrose) for 8 h. Shoot tips were osmoprotected with 35% plant vitrification solution 3 (PVS3) for 3 h, before being dehydrated with PVS3 for 2 h at $25^{\circ}C$. The encapsulated and dehydrated shoot tips were transferred to 2 mL cryotubes, suspended in 0.5 mL PVS3, and plunged directly into liquid N. High levels of shoot formation were obtained for the cv. Yeulmi (65.7%) and Yeonwhangmi (80.3%). The regrowth rates of cryopreserved samples in Yeulmi (78.9%) and Yeonwhangmi (91.3%), following culture on ammonium-free MS medium for 5 d, were much higher than those cultured on standard MS medium (65.7% and 80.3%, respectively). This encapsulation-vitrification is a promising method for the long-term preservation of sweet potato.

• Korean Journal of Environment and Ecology
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• v.24 no.3
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• pp.264-278
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• 2010

This study was carried out to describe the basic materials of the flora and vegetation for the conservation and management of the Dokdo ecosystem. The vegetation types were investigated by physionomy. 53 taxa of vascular plants were found, including 29 families, 48 genera, 49 species, 1subspecies, and 3 varieties. Among the investigated 53 taxa, it was recorded as follows: 2 Korean endemic plants included Sedum kamtschaticum var. takesimense M.Park and Campanula takesimana Nakai and 6 naturalized plants included Brassica juncea (L.) Czern., Sonchus oleraceus L., Bromus catharticus Vahl, Lepidium virginicumL., Chenopodium album L., and Ipomoea purpurea Roth. In particular, common morning glory (Ipomoea purpurea Roth) was reported for the first time in this survey of Dokdo. Based on physionomy, the main plant communities of Dokdo Island were Aster spathulifolius-Sedum oryzifolium community, Aster spathulifolius-Artemisia Japonica subsp. littoricola community, Fallopia sachalinensis-Cyrtomium falcatum community, Echinochloa crusgalli community, Echinochloa crusgalli var. oryzicola community. The debates have been continuing about a mis-identification of plants. To avoid this debate and manage naturalized and cultivated plants, taxonomist surveys and continual monitoring for the Island are required.

• Research in Plant Disease
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• v.19 no.2
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• pp.118-120
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• 2013

During the early spring of 2007 to 2009, stem rot of sweet potato (Ipomoea batatas L.) caused by Sclerotium rolfsii occurred in seedling stage grown in plastic film house at Iksan. In seedling stage of sweet potato, symptoms were initially appeared in yellowing and then the seedlings were eventually wilted. The fungus produced abundant white silky mycelium on infected tissues and soil line. Seedlings were very susceptible and died quickly once they were infected. The whole area of a petridish was rapidly covered with white mycelium on agar medium. Sclerotia began to produce after 7 days of mycelial growth and white sclerotia quickly melanized to a dark brown coloration. The causal agent isolated from the diseased plants was identified as Sclerotium rolfsii Saccardo on the basis of the morphological and cultural characteristics. All isolates of S. rolfsii caused similar symptoms on the host petioles by artificial inoculation.

• Journal of Plant Biotechnology
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• v.47 no.3
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• pp.194-202
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• 2020

The sweetpotatoes (Ipomoea batatas) generate adventitious roots (ARs) from cut stems that develop into storage roots and make for an important means of propagation. However, few studies have investigated the hormones involved in AR development in sweetpotato. In this study, the expression patterns of hormone-related genes involved in AR formation were identified using the transcriptome data. RNA-seq data from stems grown for 0 and 3 days after cutting were analyzed. In addition, hormone-related genes were identified among differentially expressed genes (DEGs) and filtered genes, and cluster analysis was used to characterize expression patterns by function. Most hormone-related regulated genes expressed 3 days after growing the cut stems were abscisic acid (ABA)-related genes, followed by ethylene- and auxin-related genes. For ABA, the biosynthesis genes (including genes annotated to NINE-CIS-EPOXYCAROTENOID DIOXYGENASE 3 (NCED3)) and signal transduction and perception genes (including genes annotated to PROTEIN PHOSPHATASE 2Cs (PP2Cs)) tended to decrease. Expression patterns of auxin- and ethylene-related genes differed by function. These results suggest that ABA, auxin, and ethylene genes are involved in AR formation and that they may be regulated in a hormone function-dependent manner. These results contribute to the identification of hormone functions during AR formation and may contribute to understanding the mechanism of AR formation in the sweetpotato.

• Journal of the Korean Society of Food Science and Nutrition
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• v.17 no.4
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• pp.348-357
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• 1988

The present work was undertaken to investigated the purification and characterization of polyphenol oxidase (PPO ; EC 1.10.3.1) in sweet potato, particularly the number of PPO isozymes, and PPO properties such as pH optimum, heat stability, substrate specificity, kinetics, and inhibitor studies. The purification achieved was 23.1 fold from crude extract with a yield of 41.5%. Eight PPO isozymes and twelve PPO isozymes were detected by disc polyacrylamide gel electrophoresis and isoelectric focusing, respectively. The specific activity of each isozyme separated by isoelectric focusing was in the range of $6,000{\sim}46,700U/mg$. This enzyme was sweet below $65^{\circ}C$ and the pH optimum of PPO occurred at 6.0-6.5. The substrate specificity of sweet potato PPO showed the high affinity toward the odiphenolic compounds. Km and Vmax for catechol were found to be 6.7 mM and $20{\triangle}A/min$, me protein, respectively. Inhibitor studies indicated that dithiothreitol was the most potent among the inhibitors used in the present work.

• Korean Journal of Plant Tissue Culture
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• v.25 no.5
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• pp.329-333
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• 1998

$\beta$-Glucuronidase (GUS) gene of Escherichia coli was introduced into sweet potato (Ipomoea batatas (L.) Lam.) cells by particle bombardment and expressed in the regenerated plants. Microprojectiles coated with DNA of a binary vector pBI121 carrying CaMV35S promoter-GUS gene fusion and a neomycin phosphotransferase gene as selection marker were bombarded on embryogenic calli which originated from shoot apical meristem-derived callus and transferred to Murashige and Skoog (MS) medium supplemented with 1 mg/L 2,4-dichlorophenoxyacetic acid and 100 mg/L kanamycin. Bombarded calli were subcultured at 4 week intervals for six months. Kanamycin-resistant calli transferred to MS medium supplemented with 0.03 mg/L 2iP, 0.03 mg/L ABA, and 50 mg/L kanamycin gave rise to somatic embryos. Upon transfer to MS basal medium without kanamycin, they developed into plantlets. PCR and northern analyses of six regenerants transplanted to potting soil confirmed that the GUS gene was inserted into the genome of the six regenerated plants. A histochemical assay revealed that the GUS gene was preferentially expressed in the vascular bundle and the epidermal layer of leaf, petiole, and tuberous root.

• Mycobiology
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• v.45 no.3
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• pp.129-138
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• 2017

In this study, we aimed to characterize fungal samples from necrotic lesions on collar regions observed in different sweetpotato growing regions during 2015 and 2016 in Korea. Sclerotia appeared on the root zone soil surface, and white dense mycelia were observed. At the later stages of infection, mother roots quickly rotted, and large areas of the plants were destroyed. The disease occurrence was monitored at 45 and 84 farms, and 11.8% and 6.8% of the land areas were found to be infected in 2015 and 2016, respectively. Fungi were isolated from disease samples, and 36 strains were preserved. Based on the cultural and morphological characteristics of colonies, the isolates resembled the reference strain of Sclerotium rolfsii. Representative strains were identified as S. rolfsii (teleomorph: Athelia rolfsii) based on phylogenetic analysis of the internal transcribed spacer and large subunit genes along with morphological observations. To test the pathogenicity, sweetpotato storage roots were inoculated with different S. rolfsii strains. 'Yulmi' variety displayed the highest disease incidence, whereas 'Pungwonmi' resulted in the least. These findings suggested that morphological characteristics and molecular phylogenetic analysis were useful for identification of S. rolfsii.

• Korean Journal of Plant Resources
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• v.23 no.3
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• pp.233-241
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• 2010

In vitro elimination of Sweet potato leaf curl virus (SPLCV) from infected sweet potato is difficult due to low number of virus-free plants obtained from meristem tip culture and long growth period required for the virus detection. In this study, efficient production of the SPLCV-free sweet potato by in vitro therapy coupled with a PCR assay for virus detection was investigated. Infected shoots cultured on Murashige and Skoog medium were treated at three different temperatures for 7 weeks followed by meristem tip culture on the medium with or without ribavirin at 50 mg/L. The regenerated plantlets were tested for virus infection by a PCR assay. The results showed that the both heat- and cold-treatments, and addition of the ribavirin did not have significant effect on efficiency of the virus elimination. The meristem size, however, greatly affected the survival rate. Meristems sized over 0.4 mm survived better than smaller ones (0.2-0.3 mm). The PCR assay was approved to be a rapid, sensitive and reliable for the SPLCV detection in regenerated plantlets. Therefore, combination of cultivating meristem tips sized 0.4-0.5 mm on the medium at $22^{\circ}C$ without ribavirin and detection of SPLCV in the regenerated plantlets by the PCR assay was an efficient system for the SPLCV elimination from infected sweet potato.

• Fisheries and Aquatic Sciences
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• v.24 no.12
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• pp.415-427
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• 2021

Wetland ecosystems act as natural freshwater purification systems, but their rich biodiversity is being threatened with the introduction of the non-native freshwater snail, Pomacea canaliculata. This study was conducted to measure the herbivory effects and growth rate of P. canaliculata on common macrophytes: Ipomoea aquatica, Ipomoea batatas, Pandanus amaryllifolius and Cucurma longa. In separate experiments, the macrophyte species were served as the snails' food as individual species and simultaneously. In the individual treatment, the growth pattern and rate were based on the snails' weight (mg/snail/day; n = 9) while the individual feeding consumption (mg/snail/day) was calculated from the leftover food. In the simultaneous treatment, the herbivory effects were evaluated as the feeding preference (%) from observations every two hours, while the total feeding consumption (mg) was calculated based on the food remaining after a 12-hour experiment (3 replicates: total n = 27). The results indicated that the growth pattern was significant for snails grazing on I. aquatica but not when other macrophyte species were eaten. The individual feeding consumption was higher when using I. aquatica than P. amaryllifolius but the growth rate for snails grazing on I. aquatica and P. amaryllifolius did not differ significantly. Meanwhile, the consumption of C. longa deterred the snails' growth rate. Although the snails consumed all the macrophytes in the individual experiment, when given the species simultaneously, the feeding preference and total feeding consumption were directed significantly more toward I. aquatica than P. amaryfollius and C. longa. We conclude that P. canaliculata is a generalist feeder given a limited choice of food but tends to show a strong feeding preference after being introduced to more food choices. These findings indicate that the introduction of P. canaliculata into wetland ecosystems may increase the herbivory effects on macrophytes, making these ecosystems vulnerable to the impact of eutrophication and biodiversity reduction.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.04a
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• pp.79-79
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• 2005