• Journal of Plant Biology
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• v.34 no.2
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• pp.107-112
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• 1991

The atrichomatous wall of ovary in Calotropis procera becomes highly pubescent in the young fruit, but scabrous I the mature fruit. The single layered epicarp develops from the outer epidermis of the ovary wall. The mesocarp which develops from the mesodermis is distinguished into outer, middle and inner zones. The central mesocarp breaks up in the course of fruit development and disintegrate to form large air chambers. The 2-3 layered lignified endocarp develops from the inner epidermis as well as from the inner mesodermis layers of the ground tissue and shows a‘parquetry pattern’of cell arrangement in surface view. The parenchymatous becomes aerenchymatous in the mature fruit. Fruit dehiscence in marginicidal (ventricidal).

• Journal of Plant Biology
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• v.34 no.2
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• pp.129-136
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• 1991

Two cell types, tip cells and hyphal cells, were found at the front of Cuscuta australis endophyte growing into the stem parenchyma of the host plant, Trifolium repens. Each tip cell developed into an elongate, filamentous hypha. The cells of both types possessed a dense cytoplasm including abundant organelles and enlarged nuclei with the deeply lobed envelope. The unevenly thick walls were observed in certain tip cells. The wall penetrated through the middle lamellae of the host cells and engulfed the debris of broken host cells. Some front cells had the plasmalemma-wall invaginations, which increased the surface area and would facilitate material uptake from the host No plasmodesmata between the host and parasite cells were found; instead, an apoplastic continuity was established by fused cell walls at the interface of the two partners. The apoplast was thought to be the main route for water and nutrients transport.nsport.

• Korean Journal of Plant Tissue Culture
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• v.27 no.2
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• pp.133-136
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• 2000

To evaluate the biological effects of dykellic acid, a novel apoptosis inhibitor, isolated from microorganism on the plant cells, the cell growth, protein contents, and superoxide dismutase (SOD) activity were investigated in suspension cultures of tobacco photomixotrophic cultured (PM) cells on 12 days after different concentration of chemical treatment. The cells were cultured in MS medium containing 0.7 mg/L 2,4-D, 0.3 mg/L kinetin, 30 g/L sucrose and 200 mM NaCl at $25^{\circ}C$ in the light (100 rpm). Dykellic acid strongly inhibited the cell growth by evaluating the cell fresh wt and the ion conductivity in the medium ($IC_{50}$/, about 20 $\mu$M). The results as inhibition of cell growth and cell wall damage were same. The compound significantly increased the protein contents and the SOD specific activity in proportion with the dosage. The results suggested that dykellic acid may have biological activity in plant cells and tobacco PM cells may be suitable biomaterials for in vitro evaluation of the biological activity of natural products.

• Journal of Ginseng Research
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• v.44 no.2
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• pp.321-331
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• 2020

Background: The patatin-related phospholipase AIII family (pPLAIIIs) genes alter cell elongation and cell wall composition in Arabidopsis and rice plant, suggesting diverse commercial purposes of the economically important medicinal ginseng plant. Herein, we show the functional characterization of a ginseng pPLAIII gene for the first time and discuss its potential applications. Methods: pPLAIIIs were identified from ginseng expressed sequence tag clones and further confirmed by search against ginseng database and polymerase chain reaction. A clone showing the highest homology with pPLAIIIβ was shown to be overexpressed in Arabidopsis using Agrobacterium. Quantitative polymerase chain reaction was performed to analyze ginseng pPLAIIIβ expression. Phenotypes were observed using a low-vacuum scanning electron microscope. Lignin was stained using phloroglucinol and quantified using acetyl bromide. Results: The PgpPLAIIIβ transcripts were observed in all organs of 2-year-old ginseng. Overexpression of ginseng pPLAIIIβ (PgpPLAIIIβ-OE) in Arabidopsis resulted in small and stunted plants. It shortened the trichomes and decreased trichome number, indicating defects in cell polarity. Furthermore, OE lines exhibited enlarged seeds with less number per silique. The YUCCA9 gene was downregulated in the OE lines, which is reported to be associated with lignification. Accordingly, lignin was stained less in the OE lines, and the expression of two transcription factors related to lignin biosynthesis was also decreased significantly. Conclusion: Overexpression of pPLAIIIβ retarded cell elongation in all the tested organs except seeds, which were longer and thicker than those of the controls. Shorter root length is related to auxinresponsive genes, and its stunted phenotype showed decreased lignin content.

• The Plant Pathology Journal
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• v.36 no.4
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• pp.346-354
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• 2020

Pectobacterium, which causes soft rot disease, is divided into 18 species based on the current classification. A total of 225 Pectobacterium strains were isolated from 10 main cultivation regions of potato (Solanum tuberosum), napa cabbage (Brassica rapa subsp. pekinensis), and radish (Raphanus sativus) in South Korea; 202 isolates (90%) were from potato, 18 from napa cabbage, and five from radish. Strains were identified using the Biolog test and phylogenetic analysis. The pathogenicity and swimming motility were tested at four different temperatures. Pectolytic activity and plant cell-wall degrading enzyme (PCWDE) activity were evaluated for six species (P. carotovorum subsp. carotovorum, Pcc; P. odoriferum, Pod; P. brasiliense, Pbr; P. versatile, Pve; P. polaris, Ppo; P. parmentieri, Ppa). Pod, Pcc, Pbr, and Pve were the most prevalent species. Although P. atrosepticum is a widespread pathogen in other countries, it was not found here. This is the first report of Ppo, Ppa, and Pve in South Korea. Pectobacterium species showed stronger activity at 28℃ and 32℃ than at 24℃, and showed weak activity at 37℃. Pectolytic activity decreased with increasing temperature. Activity of pectate lyase was not significantly affected by temperature. Activity of protease, cellulase, and polygalacturonase decreased with increasing temperature. The inability of isolated Pectobacterium to soften host tissues at 37℃ may be a consequence of decreased motility and PCWDE activity. These data suggest that future increases in temperature as a result of climate change may affect the population dynamics of Pectobacterium.

• Journal of Microbiology and Biotechnology
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• v.6 no.6
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• pp.468-473
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• 1996

The genome of tomato spotted wilt virus (TSWV) is composed of three RNA segments, S, M, and L RNA and the 5.0 kb M RNA encodes two glycoproteins Gl, G2 and NSm protein of unknown function. In an effort to investigate the function of the NSm protein, antibody was raised against NSm fusion protein overexpressed in Escherichia coli. This antibody was used to detect the NSm protein by using western blot analysis and electron microscopic observation after immunogold labelling. For the cloning of the NSm gene, total RNA extracted from a TSWV infected plant was used for cDNA synthesis and polymerase chain reaction (PCR) instead of going through time-consuming virus purification. A protein band specifically reacting to the NSm antibody was detected from TSWV inoculated plants. The NSm protein was detected in the cell wall fraction and in pellet from low speed centrifugation when the infected plant tissue was fractionated into 4 fractions. In the immuno-electron microscopic observation, gold particles were found around the plasmodesmata of infected plant tissue. These results suggest that the NSm protein of TSWV plays some role in cell-to-cell movement of this virus.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.1
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• pp.31-35
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• 2004

This experiment was performed to observe morphological changes in rice leaf tissue caused by a successive UV-B radiation. Effect of UV-B radiation on the structural alteration of tissue was not visually found, however, Photosynthate containing phosphate was sharply reduced in proportion with an increase of UV-B radiation. Fundamental components of cuticle layer were being degraded after 6 h of UV-B radiation compared to the control. UV-B-induced mesophyll cell appeared altered because of water stress, the shape of chloroplast appeared to be considerably shrunk and chloroplast thylakoid membranes were severely destructed. Primary cell wall of UV-B-stressed tissue was entirely scattered or disappeared, and the secondary cell wall due to lignin synthesis and deposition resulted in being thickened, almost 2-times, compared with the control.

• The Plant Pathology Journal
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• v.29 no.4
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• pp.454-459
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• 2013

The Potexvirus Alternanthera mosaic virus (AltMV) has multifunctional triple gene block (TGB) proteins, among which our studies have focused on the properties of the TGB1 protein. The TGB1 of AltMV has functions including RNA binding, RNA silencing suppression, and cell-to-cell movement, and is known to form homologous interactions. The helicase domains of AltMV TGB1 were separately mutated to identify which regions are involved in homologous TGB1 interactions. The yeast two hybrid system and Bimolecular Fluorescence Complementation (BiFC) in planta were utilized to examine homologous interactions of the mutants. Helicase motif I of AltMV TGB1 was found to be critical to maintain homologous interactions. Mutations in the remaining helicase motifs did not inhibit TGB1 homologous interactions. In the absence of homologous interaction of TGB1, subcellular localization of helicase domain I mutants showed distinctively different patterns from that of WT TGB1. These results provide important information to study viral movement and replication of AltMV.

• The Plant Pathology Journal
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• v.15 no.2
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• pp.127-130
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• 1999

Cytological changes of cowpea root at the early stage of root nodule formation (within 5 days after inoculation) were viewed by light and electron microscopy. The root region affected by the rhizobial infection, which was composed of a redial array of cortical cells, had prominent cell divisions, mostly anticlinal in the inner cortical cells and in addition oblique and periclinal in the outer cells. An infected root hair cell (or root hair-producing epidermal cell) had numerous infection threads and degenerated cytoplasm. Module meristem was formed adjacent to the infected root hair cell, and characterized by dense cytoplasm, prominent nucleus, numerous small vacuoles, and increased plastids, containing infection threads as well. Bacterial cells were dividing inside the infection thread, the wall materials of which appeared to be dissolved ad accumulated in small vacuoles. inner cortical cells contiguous to the nodule meristem appeared to be actively dividing and dedifferentiating; however, they were not infected by the rhizobia. These structural characteristics are similar to those in the Bradyrhizobium-soybean association previously reported, and may reflect the similar cytological process in cowpea in the early nodule formation.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.35-35
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• 2017

How do plants take up water from soils especially when water is scarce in soils? Plants have a strategy to respond to water deficit to manage water necessary for their survival and growth. Plants regulate water transport inside them. Water flows inside the plant via (i) apoplastic pathway including xylem vessel and cell wall and (ii) cell-to-cell pathway including water channels sitting in cell membrane (aquaporins). Water transport across the root and leaf is explained by a composite transport model including those pathways. Modification of the components in those pathways to change their hydraulic conductivity can regulate water uptake and management. Apoplastic barrier is modified by producing Casparian band and suberin lamellae. These structures contain suberin known to be hydrophobic. Barley roots with more suberin content from the apoplast showed lower root hydraulic conductivity. Root hydraulic conductivity was measured by a root pressure probe. Plant root builds apoplastic barrier to prevent water loss into dry soil. Water transport in plant is also regulated in the cell-to-cell pathway via aquaporin, which has received a great attention after its discovery in early 1990s. Aquaporins in plants are known to open or close to regulate water transport in response to biotic and/or abiotic stresses including water deficit. Aquaporins in a corn leaf were opened by illumination in the beginning, however, closed in response to the following leaf water potential decrease. The evidence was provided by cell hydraulic conductivity measurement using a cell pressure probe. Changing the hydraulic conductivity of plant organ such as root and leaf has an impact not only on the speed of water transport across the plant but also on the water potential inside the plant, which means plant water uptake pattern from soil could be differentiated. This was demonstrated by a computer simulation with 3-D root structure having root hydraulic conductivity information and soil. The model study indicated that the root hydraulic conductivity plays an important role to determine the water uptake from soil with suboptimal water, although soil hydraulic conductivity also interplayed.