• Journal of Environmental Science International
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• v.25 no.9
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• pp.1289-1297
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• 2016

The walls of guard cells have many specialized features. Guard cells are present in the leaves of bryophytes, ferns, and almost all vascular plants. However, they exhibit considerable morphological diversities. There are two types of guard cells: the first type is found in a few monocots, such as palms and corn, and the other is found in most dicots, many monocots, mosses, ferns, and gymnosperms. In corns, guard cells have a characteristic dumbbell shape with bulbous ends. Most dicot and monocot species have kidney-shaped guard cells that have an elliptical contour with a pore at its center. Although subsidiary cells are common in species with kidney-shaped stomata, they are almost always absent in most of the other plants. In this study, there were many different stomatal features that were associated with kidney-shaped guard cells, but not dumbbell shaped guard cells, which are present in most grasses, such as cereals. Each plant investigated exhibited different characteristic features and most of these plants had kidney-shaped guard cells. However, the guard cells of Chamaesyce supina Mold, were often more rectangular than kidney-shaped. In contrast, Sedum sarmentosum guard cells were of the sink ensiform type and in Trifolium repens, the guard cells exhibited a more rhombic shape. Therefore, kidney-shaped guard cells could be divided into a number of subtypes that need to be investigated further.

• Journal of Plant Biotechnology
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• v.37 no.2
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• pp.133-143
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• 2010

Rice (Oryza sativa) is a major cereal crop that has been developed as a monocot model species. In past decades rice researchers have established valuable resources for functional genomics in rice, such as complete genome sequencing, high-density genetic maps, a full length cDNA database, genome-wide transcriptome data, and a large number of mutants. Of these, rice mutant lines are very important to definitively determine functions of genes associated with valuable agronomic traits. In this review we summarize the progress of functional genomics approaches in rice using T-DNA mutants.

• Korean Journal of Agricultural Science
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• v.44 no.3
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• pp.318-324
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• 2017

With the development of next-generation sequencing (NGS), a cutting-edge technology, genotype-by-sequencing (GBS) became available at a low cost per sample. GBS makes it possible to customize the process of library preparation to obtain high-quality single nucleotide polymorphisms (SNPs) in the most efficient way. However, a GBS library is hard to construct due to fine-tuning of concentration of each reagent and set-up. The major reason for this is the presence of undigested genomic DNA (gDNA) owing to the efficiency of different restriction enzymes for different species with unknown reasons. Therefore, this proof-concept study is to demonstrate the unpredictable patterns of enzyme digestion from various plants in order to make the reader aware of the caution needed when choosing restriction enzymes for their GBS library preparations. Indeed, no pattern was found for the digestibility of gDNA samples and restriction enzymes in the current study. We suggest that more data should be accumulated on this matter to help researchers who want to apply GBS technologies in a variety of genetic approaches.

• BMB Reports
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• v.51 no.11
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• pp.578-583
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• 2018

Telomeres are specialized nucleoprotein complexes that function to protect eukaryotic chromosomes from recombination and erosion. Several telomere binding proteins (TBPs) have been characterized in higher plants, but their detailed in vivo functions at the plant level are largely unknown. In this study, we identified and characterized OsTRFL1 (Oryza sativa Telomere Repeat-binding Factor Like 1) in rice, a monocot model crop. Although OsTRFL1 did not directly bind to telomere repeats $(TTTAGGG){_4}$ in vitro, it was associated with telomeric sequences in planta. OsTRFL1 interacted with rice TBPs, such as OsTRBF1 and RTBP1, in yeast and plant cells as well as in vitro. Thus, it seems likely that the association of OsTRFL1 with other TBPs enables OsTRFL1 to bind to telomeres indirectly. T-DNA inserted OsTRFL1 knock-out mutant rice plants displayed significantly longer telomeres (6-25 kb) than those (5-12 kb) in wild-type plants, indicating that OsTRFL1 is a negative factor for telomere lengthening. The reduced levels of OsTRFL1 caused serious developmental defects in both vegetative and reproductive organs of rice plants. These results suggest that OsTRFL1 is an essential factor for the proper maintenance of telomeres and normal development of rice.

• Journal of Plant Biotechnology
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• v.2 no.2
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• pp.89-96
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• 2000

For large DNA fragment transformation in dicots and monocots, BIBAC2 vector system was applied to Arabidopsis thaliana and Oryza sativa L. cv. Jinmi as a model plant, respectively. For Arabidopsis, the Th1 gene in T23L3 BAC clone whose size is about 90 kb was used as the target gene source for transformation. Because T23L3 BAC clone was originally constructed in pBelloBAC11, the target gene was reconstructed into BIBAC2. As the results of reconstruction, 476 colonies were survived in selection medium containing 40 mg/L kanamycin. In colony hybridization analysis, 24 out of 476 colonies exhibited positive signals. In the pulsed-field gel electrophoresis analysis, 11 out of 24 positive clones exhibited the band at the location of 90 kb. In Southern hybridization, positive signal band at the location of 90 kb was observed in all 11 transformants. Using these verified clones, Agrobacterium-mediated transformation was applied to Arabidopsis thaliana th1-201 mutant for genetic complementation test. Twelve thousands T$_1$ seeds were harvested, and antibiotic selection test is being analyzed to verify whether these seeds were transformed. for rice, COR356 that contains 150 kb human genomic DNA in a BIBAC2 vector was used as the target gene. As the results of transformation, 151 out of 210 co-cultivated calli were survived in selection medium containing 5 mg/L hygromycin, and 45 out of 151 survived calli were regenerated into plants. Transformation efficiency was 21.6%. Progeny test using 71 seeds is being analyzed now. These results provide the potential that large DNA fragments can be transferred into both dicots and monocot by Agrobacterium-mediate d transformation system.

• The Plant Pathology Journal
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• v.24 no.4
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• pp.461-468
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• 2008

An endophytic bacterial strain YC5480 producing antifungal and phytotoxic compounds simultaneously was isolated from the surface sterilized root of Artemisia sp. collected at Jinju area, Korea. The bacterial strain was identified as a species of Pseudomonas brassicacearum based on its 16S rRNA gene sequence analysis and physiological and biochemical characteristics. The seed germination and growth of monocot and dicot plants were inhibited by culture filtrate (1/10-strength Tryptic Soy Broth) of the strain. The germination rate of radish seeds in the culture filtrate differed in various culture media. Only 20% of radish seeds germinated in the culture media of 1/2 TSB for 5 days incubation. Mycelial growth of fungal pathogens, Colletotrichum gloeosporioides, Fusarium oxysporum and Phytophthora capsici was also inhibited by the culture filtrate of the strain YC5480. An antifungal compound, KS-1 with slight inhibitory activity of radish seed germination at 1,000 ppm and a seed germination inhibitory compound, KS-2 without suppression of fungal growth were produced simultaneously in TSB. The compounds KS-1 and KS-2 were identified to be 2,4-diacetylphloroglucinol (DAPG) and 2,4,6-trihydroxyacetophenone (THA), respectively.

• BMB Reports
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• v.40 no.6
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• pp.845-852
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• 2007

The highly evolved flowers of orchids have colorful sepals and fused columns that offer an opportunity to discover new genes involved in floral development in monocotyledon species. In this investigation, we cloned and characterized the homologous PISTALLATA-like (PI-like) gene PhPI15 ($\underline{Ph}alaenopsis$ $\underline{PI}$ STILLATA # $\underline{15}$), from the Phalaenopsis hybrid cultivar. The protein sequence encoded by PhPI15 contains a typical PI-motif. Its sequence also formed a subclade with other monocot PI-type genes in phylogenetic analysis. Southern analysis showed that PhPI15 was present in the Phalaenopsis orchid genome as a single copy. Furthermore, it was expressed in all the whorls of the Phalaenopsis flower, while no expression was detected in vegetative organs. The flowers of transgenic tobacco plants ectopically expressing PhPI15 showed male-sterile phenotypes. Thus, as a Class-B MADS-box gene, PhPI15 specifies floral organ identity in orchids.

• BMB Reports
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• v.41 no.5
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• pp.369-375
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• 2008

Polygonatum cyrtonema Lectin (PCL), which is classified as a monocot mannose-binding lectin, has received great regards for its uniquely biological activities and potentially medical applications in cancer cells. This paper was initially aimed to study apoptosis of PCL on Hela cells. Thus, 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) method was carried out. Through observation of cell morphologic changes and Lactate dehydrogenase (LDH) activity-based cytotoxicity assays, PCL induced HeLa cell apoptosis in a dose-dependent manner. To further gain structural basis, multiple alignments, homology modeling and docking experiments were performed to analyze the correlation between its biological activities and mannose-binding sites. Eventually, considering docking data, chemical modification properties on the three mannose-binding sites were analyzed by a series of biological experiments (e.g., hemagglutinating and mitogenic activity assays, fluorescence and Circular Dichrosim (CD) spectroscopy) to profoundly identify the role of some key amino acids in the structure-function relationship of PCL.

• The Korean Journal of Pesticide Science
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• v.11 no.1
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• pp.52-58
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• 2007

ALA (5-aminolevulinic acid) has been proposed as a tetrapyrrole-dependent photodynamic herbicide and insecticide by the action of the protoporphyrinogen IX oxidase (Protox IX). The present study was conducted to determine growth responses of plant and insects to ALA, biodegradable biopesticidal substance. In the paddy condition experiment, plant height and shoot fresh weight of barnyardgrass (Echinochloa crus-galli) was more reduced by ALA than rice plants, even though both plant species show great phytotoxicity. Hairy crabgrass (Digitaria sanguinalis), a monocot weed, was more sensitive to ALA at 5mM under upland condition when ALA applied on the foliage, compared with soybean (Glycine max) as a dicot crop. ALA solutions were tested for their insecticidal and larvicidal activities against Spodaptera exigua (Hubner) and Tetranychus urticae Koch. by foliar application and leaf-dipping method. The result showed higher insecticidal activity of ALA at 10mM and its mixture with insecticide luferon against S. exigua. Strongest insecticidal activity against T. urticae was observed from the ALA solution at 10mM 72 days after application. This results show that ALA solution had potent herbicidal and insecticidal activities against agricultural pests even though their activities were lower than those of synthetic pesticides.

• Korean Journal of Plant Tissue Culture
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• v.28 no.5
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• pp.277-281
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• 2001

Embryogenic callus induction and plant regeneration methods were developed for native Kentucky bluegrass (Poa pratenes L.) ecotypes. Mature caryopses and immature inflorescences (20 mm in length) of 4 native ecotypes and 5 foreign cultivars were plated on MS medium (30 g/L sucrose, 3 g/L Phytagel) supplemented with 1 mg/L 2,4-D, and cultured in the dark at 24$^{\circ}C$. Most explants formed calli, but more embryogenic calli were induced from the explants of immature inflorescences than caryopses which produced mostly non-embryogenic rooty calli. In P77 ecotypes, immature inflorescence explants formed embryogenic calli with the rate of 62~95%, and those of field-grown plants were more efficient than greenhouse-grown ones in embryogenic callus induction. Plantlets were regenerated from the embryogenic calli when they were transferred to hormone-free MS medium, and grew to maturity without morphological variations in greenhouse.