• Asian Journal of Turfgrass Science
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• v.13 no.1
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• pp.21-28
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• 1999

The seeds of Zoysiagrass (Zoysia japonica Steud.) were soaked with GA3 50 ppm and primed with CaCl2 at -1.0 MPa for 4days at 23$^{\circ}C$ to identify presoaking and priming regimes that may improve germination in saline condition and with PEG 8000 at high temperature. Presoaked, primed, and untreated seeds were then germinated at 30 and $35^{\circ}C$. NaCl salinity stress consistently decreased the rate of germination of zoysiagrass seed. GA3 or CaCl2 alleviated the inhibitory effect of salinity on germination. However, total percent germination (G) and T50 of untreated control seeds significantly decreased and prolonged at $30^{\circ}C$ and $35^{\circ}C$ as NaCl salinity stress increased. Presoaked seeds with GA3 50 ppm for 4 days at $23^{\circ}C$ had significantly higher germination and lower T50 than untreated or primed with CaCl2 at -1.0 MPa for 4days at $23^{\circ}C$m and overcame the inhibitory effect of germination derived from PEG 8000. In addition, presoaked seed had higher, faster, and more uniform germination than untreated seeds after sowing in growing media in greenhouse.

• Asian Journal of Turfgrass Science
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• v.24 no.2
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• pp.88-96
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• 2010

Zoysiagrass, especially Jungji implicating medium-leaf type zoysiagrass has been widely used in South Korea recently. This study was carried out to classify 36 selected medium-leaf type zoysiagrass accessions compared to 5 basic zoysiagrass species using RAPDs. Morphological characteristics such as leaf width, leaf angle, leaf sheath length, existance of trichomes and stolon color were measured as useful characteristics for identification of species in Zoysia genus. Nineteen RAPD markers were identified using 8 selected random primers. The dissimilarity coefficient of variants ranged from 0 to 0.736. Three zoysiagrass groups were clustered by dissimilarity coefficient analysis. Group 1 consisted of Z. japonica and some US varieties including 'Zenith' and 'Meyer'. Group 2 consisted of Z. sinica, Z. macrostachya and Korean commercial varieties such as 'Anyang', 'Samdeock', and 'Pyeongdong' medium-leaf type grasses. Group 3 was genetically distinct from Group 1 and Group 2, and included Z. matrella and Z. tenuifolia. 'Anyang', 'Samdeock', and 'Pyeongdong' medium-leaf type zoysiagrasses showed very close genetic relationship with Z. sinica and Z. macrostachya.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.100-100
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• 2018

Zoysia japonica Steud.(Zj) is a typical warm-season Korean lawn grass, which is used in many places such as river banks, roadside and soccer fields in Korea. Recently, it has also been used in school yards and the Saemangeum reclaimed land to reduce water pollution. Although the cultivated area of turfgrass is steadily increasing worldwide, it grows fast requiring frequent mowing and is difficult to grow in shady areas and the cold region. Therefore this study aims searching for useful gene(s) to develop abiotic stress tolerant and dwarf zoysiagrass. We isolated Ycf4 gene based on the sequence from Oryza sativa Japonica through RT-PCR and RACE PCR. Ultimately, open reading frame (ORF) of ZjYcf4 was 558bp long, encoding a protein of 186 amino acid residues. NCBI blast results showed that the ZjYcf4 protein is evolutionarily closely related to Ycf4 protein from Zoysia macrantha and Setaria italica (100% and 98%, respectively). To determine whether ZjYcf4 was involved in environmental stress in wild-type zoysiagrass, expression patterns of the gene were analyzed by real-time PCR under salt, cold and dark conditions. They were analyzed after each stress treatment for 3 hours. In salt and cold stresses, the expression was higher compared to control (3-fold and 1.5-fold, respectively), although there was a 1.6-fold decrease in expression under dark stress treatment. As reported previously, we suggest that ZjYcf4 gene affects abiotic stress such as salt, cold and dark.

• Journal of Plant Biotechnology
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• v.47 no.4
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• pp.316-323
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• 2020

This study aimed to evaluate the potential allergenicity and oral toxicity of the phosphinothricin acetyltransferase (PAT) protein expressed in Zoysia japonica, a herbicide-tolerant genetically modified (GM) zoysiagrass. In silico analysis of PAT showed no similarities with any known allergenic or toxic proteins, with <35% amino acid sequence homology with known allergens across a length of 80 amino acids and no continuous eight amino acid identity with known allergens. The PAT protein expressed in Z. japonica degraded very rapidly in the simulated gastric fluid in the presence of pepsin, and, no glycosylation of PAT was observed. The oral toxicity test revealed no mortality or toxic effect in mice following PAT administration at 4,000 mg/kg body weight. Our findings indicate that the PAT protein expressed in Zoysia japonica does not exhibit allergenic or toxic properties.

• Weed & Turfgrass Science
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• v.7 no.3
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• pp.247-257
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• 2018

This study was conducted to find out the optimum silicate fertilization for improving the quality and density of zoysiagrass (Zoysia japonica Steud.), the growth of zoysiagrass and changes in chemical properties of soil in field experiments treated with different levels of silicate fertilizer during 3 years from 2012 to 2014. An increase in the silicate fertilizer from 100, 200, to $400kg\;10a^{-1}$ led to a significant increase in the fresh and dry weight of shoots and stolons, the number of shoots and length of stolon, but were not significantly different between 200 and $400kg\;10a^{-1}$. Moreover, soil pH, EC and the contents of available $SiO_2$ were increased as the rate of silicate fertilizer application increased. Thus, these results demonstrated that the silicate fertilizer rate for maximum growth of zoysiagrass was $200kg\;10a^{-1}$ in consideration of improving growth of zoysiagrass and the chemical property of the soil.

• Weed & Turfgrass Science
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• v.5 no.4
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• pp.256-259
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• 2016

An obligate plant pathogenic fungus Puccinia zoysiae Dietel, the causal agent of rust disease, which is implicated in the damage of zoysiagrass (Zoysia spp.) in Korea. The fungus is one of the important pathogens, which attacks and colonizes susceptible zoysiagrass. Zoysia rust disease was observed in Jangseong, Hoengseong and Hapcheon in 2014 and 2015, Korea. The typical symptoms of the disease appeared first as small white spots on the leaf and stem of zoysiagrass plants, and turn brownish, dark brown spores revealed on the lesions. Uredospores were light brown in color, ellipsoid or spherical in shape and $22.0{\sim}25.0{\times}15.0{\sim}17.5{\mu}m$ in size. On the basis of the morphological characteristics, the fungus was identified as P. zoysiae. Pathogenicity of the fungus was proved by artificial inoculation on Z. japonica. The rust disease firstly appeared approx. early or middle June and then increased middle of October in Korea. In field, Z. matrella ecotypes were more resistant than Z. japonica ecotypes against the pathogen. Disease response against the pathogen was different among ecotypes of each species, respectively.

• Proceedings of the Korean Society of Crop Science Conference
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• 2000.04a
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• pp.222-223
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• 2000

• Korean Journal of Weed Science
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• v.31 no.2
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• pp.199-204
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• 2011

This experiment was carried out to investigate the growth responses of zoysiagrass (Zoysia japonica Steud.) as affected by prohexadione-calcium foliar application for the effective labour saving and cost down management in the lawn yard, field and golf course etc. The leaf growth of zoysiagrass treated with prohexadione-calcium one day after mowing was significantly slow compared to the untreated plot. And the effect was continued up to 50 days. The growth inhibition rate at the treated plot was 46 to 50% compared to untreated plot and the leaf widths treated with prohexadione-calcium were narrower than control plot. The change of leaf dry weight 10 days after prohexadione-calcium treated was significantly shown less speedy than untrated plot and the results were continued up to 40 days after application. The SPAD values of the leaf colour were increased in the treated plots and continued for 40 days more.

• Journal of Plant Biotechnology
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• v.37 no.4
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• pp.400-407
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• 2010

Zoysiagrass (Zoysia japonica Steud.), also called Korean or Japanese lawngrass, is the most popular warm-season turfgrass in Korea and is widely used for home lawns, parks, roadsides, golf courses and athletic fields. Its use is rapidly expanding in Korea and the other countries, due to its excellent characteristics which include tolerance to heat, drought and salinity. As the utilization area of this turfgrass increases, there is an increase in the demand for improved cultivars with disease and insect tolerance or with herbicide-tolerance or with extended greening periods. Conventional breeding methods have been used to improve the traits described above with limited success. However, with the advances in biotechnology, genetic transformation can be utilized for turfgrass improvement. In this paper, we review recent progress in biotechnological improvement of zoysiagrass and discuss future molecular breeding of this species.

• Journal of Plant Biotechnology
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• v.38 no.2
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• pp.105-116
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• 2011

Transgenic zoysiagrass (Zoysia japonica Steud.) expressing the bar gene inserted in the plant genome has been generated previously through Agrobacterium tumefaciens-mediated transformation. The GM zoysiagrass (event: JG21) permits efficient management of weed control of widely cultivated zoysiagrass fields, reducing the frequency and cost of using various herbicides for weed control. Now we have carried out the environmental risk assessment of JG21 prior to applying to the governmental regulatory agency for the commercial release of the GM turf grass outside of test plots. The morphological phenotypes, molecular analysis, weediness and gene flow from each test plot of JG21 and wild-type zoysiagrasses have been evaluated by selectively analyzing environmental effects. There were no marked differences in morphological phenotypes between JG21 and wild-type grasses. The JG21 retained its stable integration in the host plant in T1 generation, exhibiting a 3:1 segregation ratio according to the Mendelian genetics. We confirmed the copy number (1) of JG21 by using Southern blot analysis, as the transgenic plants were tolerant to ammonium glufosinate throughout the culture period. From cross-fertilization and gene flow studies, we found a 9% cross-pollination rate at the center of JG21 field and 0% at distances over 3 m from the field. The JG21 and wild-type zoysiagrass plants are not considered "weed" because zoysiagrasses generally are not dominant and do not spread into weedy areas easily. We assessed the horizontal gene transfer (HGT) of the transgene DNA to soil microorganisms from JG21 and wild-type plants. The bar gene was not detected from the total genomic DNA extracted from each rhizosphere soil of GM and non-GM Zoysia grass fields. Through the monitoring of JG21 transgene's unintentional release into the environment, we found no evidence for either pollen mediated gene flow of zoysiagrass or seed dispersal from the test field within a 3 km radius of the natural habitat.