• Korean journal of applied entomology
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• v.24 no.4 s.65
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• pp.173-177
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• 1986

This study was carried out to see what makes the 'dark grey cutworm', Agrotis tokionis Butler, inflict less damage in P.E. film-mulched tobacco fields than in nonmulched ones. In field plot experiment, the damage ratio of tobacco seed lings in mulched plots(m) was reduced by 63% compared with that in non mulched ones(n). The altered environments did not affect the cutworm in mortality, which was confirmed by recovery ratio, location of larvae in soil, and developmental age. But the m/n value and damage ratio in plots of different mulching methods strongly suggest that the P.E. film itself prevent larvae from cutting the plants. Larval mortality was rapidly increased between the end of July and the end of August.

• The Plant Pathology Journal
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• v.18 no.6
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• pp.323-327
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• 2002

A rod-shaped virus was isolated from pepper showing mild mosic during the winter growing seasons of 2001 and 2002 in Korea. Based on its biological reactions, serological relationships, reverse transcription-poly-merase chain reaction (RT-PCR) using specific primers, and nucleotide sequence analysis of coat protein (CP) gene, the isolated virus was identified as Tobacco mild green mosaic virus (TMGMV) and designated as Korean pepper isolate (TMGMV-KP). Crude sap from infected tissue was mechanically transmitted to various indicator plants, which produced characteristic symptoms of tobamovirus infection. However, no symptom was observed in Gomphorena globosa. In RT-PCR assays with specific primers toy respective detection of TMGMV, Tobacco mosaic virus (TMV), Pepper mild mottle virue (PMMoV), and Tomato mosaic virus (ToMV), a single strong band of about 500 bp in length was produced from the sample used only with TMGMV primers. The amplified DNA was cloned and the nucleotide sequence was determined. Sequence comparisons with the CP gene of other tobamoviruses indicated that TMGMV-KP shared 99.3％ identity with TMGMV Japanese isolate and only 59.1, 58.6, and 58.1％ identity with TMV, PMMoV and ToMV, respectively. This is the first report of TMGMV in Korea.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.2
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• pp.207-211
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• 1981

The effect of plant populations - 16,667, 14,285, 12,499 or 10,7l4/10a on the agronomic characteristics of an aromatic tobacco, Sohyang was investigated for two years. The growth and number of suckers produced decreased as the population increased. The leaf area index (L.A.I) was higher in thinner planting, but there was no significant difference in weight per unit leaf area between treatments. Yield was highest, 1 24 kg/ l0a, in 16,667 plantings per l0a, but quality was not different among densitites tested. Similar trends were observed in monetary value per l0a. Concentrations of total alkaloids and nitrogen were low in denser planting, but no significant difference was observed in total sugar. The results suggest that about 16,000/10a more would be optimum number of plants for Sohyang.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.6
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• pp.602-606
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• 1994

The study was conducted to investigate the relationships between the value of fresh leaf lengh ${\times}$ width and actual fresh or cured leaf area, Cured leaf weight of cutter and leaf in Burley tobacco plants. In all tested varieties, Actual fresh leaf area or cured leaf area, cured leaf weight was high significantly correlated with the value of fresh leaf length ${\times}$ width. The linear regression equation between them could be exploited for rapid and easy estimation of either fresh or cured leaf area, cured leaf weight. Highly significant correlation between fresh leaf area and cured leaf area or cured leaf weight was confirmed and a linear regression equation was also obtained for easy estimation of cured leaf area or cured leaf weight.

• Korean Journal of Plant Tissue Culture
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• v.24 no.1
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• pp.63-69
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• 1997

Erythropoietin (EPO) is a glycoprotein that mediates the growth and differentiation of erythroid progenitors. In order to produce recombinant human erythropoietin in tobacco plant, the EPO genomic DNA (5.4 kb) was cloned into plant expression vectors, pBI$\Delta$GUS121, pBD$\Delta$GUS121 and pPEV-1, and introduced in Nicotiana tabacum (var. Xanthi) via Agrobacterium tumefaciens-mediated transformation. After selection on MS media containing kanamycin (Km), 10 Km-resistant plants were obtained per each construct. The correct integration of EPO genomic DNA in the genome of transgenic plant was confirmed by polymerase chain reaction (PCR). Northern blot showed that transcripts of 1.8 kb length were produced in leaves of the plants, but there was no difference of mRNA amount according to promoter number and 5'-untranslated sequence (UTS). The proteins obtained from leaves of transgenic plants were immunologically detected by Western blot using rabbit anti-human EPO polyclonal antibody. The expressed protein appeared as smaller band of apparent mass of 30 kDa as compared to the EPO protein from human urine (37 kDa), suggesting that the modification (glycosylation) system in tobacco plant might be different from that of mammalian cells.

• Korean journal of applied entomology
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• v.37 no.1
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• pp.31-37
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• 1998

Random amplified polymorphic DNA (RAPD) markers were used to analyze genetic similarity among 8 clones of apierous green peach aphid, two types (M. persicae Sulzer and M. nicotianae lack man) classified by their mo~hologi~cahla raters and host preference (Blackman, 1987), collected from tobacco plants. The genetic variation among these clones was evaluated by polymerase chain reaction amplification with 20 random primers. The higher GC contents of primers, the better in amplification efficiency of PCR reaction in general. The genetic similarities among eight aphid clones were analyzed from UPGMA (unweighted pair group average method) cluster analysis based on simple matching coefficient. The range of genetic similarity coefficients was 0.414 to 0.808. The most close relationship among the clones was similarity coefficient of 0.808 between the PG2 and the PG3 clone. The eight aphid clones analyzed were clustered into three groups by the genetic similarity coefficient. The first group, PG1, PG2, PG3 clone including in M. persicae type by their morphological characters and RED clone in M. nicotianae type was clustered at the genetic similarity coefficient of 0.643. The second group, GR1, GR2, BRN in M. nicotianae type was at the 0.636;and the third group was DBR clone in M. persicae type. The results did not indicate any correlation between m&-phological types (M. persicae and M. nicotianae) and RAPD polymorphism. We could not detect any obvious genetic relationships of the two morphological types of the green peach aphid collected from tobacco plants.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.2
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• pp.212-217
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• 1981

The evaluate the effect of plant spacing on cured leaf of burley tobacco, the row spacings divided to 90, 105, 120cm and hill spacings to 30, 35, 40cm within each row. Growth amount per plant increased with thinner row and wider hill spacing in the same planting density. Relative light intensity increased with thinner row spacing in cutters and leaf and showed the positive correlation with quality. When the planting density was equal, the wider hill spacings, the more effective in utillization of solar radiation. The more plants per l0a were, the greater yield was obtained, and in the case of 3,200 plants per 10a (the most dense planting plot) was 267kg. But, quality, total-alkaloid and total-nitrogen content decreased with dense planting. Value per 10a was highest in the plots of 90 $\times$ 40cm and $105{\times}40cm$. In conclusion the optimum density level was 2,400 to 2,700 plants per 10a and spacing of tobacco either in 105 $\times$ 35 cm or 105 $\times$ 40cm seems to be most appropriate.

• Korean Journal of Weed Science
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• v.14 no.1
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• pp.71-80
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• 1994

Nepal, with its unique geographical and ecological features due to its abrupt rise in altitude, plays significant role in biological evolution. Existence of numerous wild relatives of the present-day cultivated agricultural crop plants in this small Himalayan nation may serve as a potential source of several yet unidentified desirable genes that are needed for future incorporation in the improvement of cultivated crop plants. This report includes 82 different wild relatives of 41 genera under 19 families of 37 agricultural crops of Nepal(Table 1). It serves as the sample of the glossary of these wild relatives of crop plants in Nepal. Under food grain crop plants of gramineae, leguminoceae and polygonaceae families, 16 different wild species namely wild rices(7 species), wild relatives of wheat plant(3 species), wild arhar(3 species), wild fingermillets(1 species) and wild buckwheat(2 species) have been identified in different parts of the country. Similarly, under vegetable crop plants of Araceae, Amaranthaceae, Crucifereae, Cucurbitaceae, Dioscoreaceae, Labiteae, Leguminosae, Liliaceae, Malvaceae, Polygonaceae, Solanaceae and Umbellifereae, 37 different wild species-wild colocasia(1 species), wild amaranths(3 species), wild leafy vegetables(2 species), wild gourds(3 species), wild cucumber(1 species), wild yams(4 species), wild mints(3 species), wild fenugreeks(4 species), wild pea(1 species), wild beans(3 species), wild garlics(2 species), wild spinach(3 species), wild lady's finger(1 species), wild spinach(3 species), wild eggplants(2 species) and wild carrot(one species) have also been identified. In case of wild relatives of cultivated orchard plants, 11 different wild species namely wild mango(one species), wild banana(one species), wild strawberry(one species), wild pear(one species), wild cherries(2 species), wild apple(one species) and wild grapes(3 species) have been identified, Among 19 different wild species of economic crop plants, five wild species of sugarcane, one species of wild sunhemp, two wild relatives of cotton, three wild relatives of rose, two wild species of tobacco, four wild species of turmeric and two wild species of tea have also been identified. This report includes only sample of the total wild species of the present-day cultivated agricultural crop plants. Further exploration on this economic botany will help the country in cataloging the wild relatives of cultivated crop plants and their future use in crop improvement.

• Korean journal of applied entomology
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• v.56 no.1
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• pp.19-28
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• 2017

Polydnaviruses (PDVs) are a group of double-stranded DNA viruses symbiotic to some endoparasitoid wasps. Cotesia plutellae bracovirus (CpBV) is a PDV symbiotic to an endoparasitoid wasp, C. plutellae, parasitizing young larvae of Plutella xylostella. An early expressed gene, CpBV-ELP1, plays an important role in the parasitism by suppressing host cellular immunity by its cytotoxic activity against hemocytes. This study aimed to test its oral toxicity against insect pest by expressing it in a recombinant tobacco plant. A recombinant CpBV-ELP1 protein was produced using a baculovirus expression system and secreted to cell culture medium. The cell cultured media were used to purify CpBV-ELP1 by a sequential array of purification steps: ammonium sulfate fractionation, size exclusion chromatography, and ion exchange chromatography. Purified rCpBV-ELP1 exhibited a significant cytotoxicity against Spodoptera exigua hemocytes. CpBV-ELP1 was highly toxic to the fifth instar larvae of S. exigua by injection to hemocoel. It also showed a significant oral toxicity to fifth instar larvae of S. exigua by a leaf-dipping assay. CpBV-ELP1 was cloned into pBI121 vector under CaMV 35S promoter with opaline synthase terminator. Resulting recombinant vector (pBI121-ELP1) was used to transform Agrobacterium tumefaciens LBA4404. The recombinant bacteria were then used to induce callus of a tobacco (Nicotiana tabacum Xanthi) leaves and subsequent generation (T1) plants were selected. T1 generation tobacco plants expressing CpBV-ELP1 gave significant insecticidal activities against S. exigua larvae. These results suggest that CpBV-ELP1 gene can be used to control insect pests by constructing transgenic crops.

• Korean journal of applied entomology
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• v.54 no.1
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• pp.7-15
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• 2015

CpBV (Cotesia plutellae bracovirus) is a polydnavirus and encodes a cystatin (CpBV-CST1) gene. Its overexpression suppresses insect immunity and alters insect developmental processes. This study aimed to construct a genetically modified (GM) tobacco to further explore the physiological function of the viral cystatin and to apply to control insect pests. To this end, the transgenic tobacco lines were screened in expression of the target gene and assessed in insecticidal activity. A recombinant vector (pBI121-CST) was prepared and used to transform a bacterium, Agrobacterium tumefasciens. The transformed bacteria were used to generate transgenic tobacco lines, which were induced to grow callus and resulted in about 92% of shoot regeneration. The regenerated plants were screened by PCR analysis to confirm the insertion of the target gene in the plant genome. In addition, the expression of the target gene was assessed in the regenerated plants by quantitative real-time PCR (qRT-PCR). The qRT-PCR analysis showed that the transgenic line plant expressed the target gene about 17 times more than the control tobacco, indicating a stable insertion and expression of the target gene in the transgenic tobacco line. The insecticidal activity was then analyzed using the screened transgenic tobacco lines against the teneral 1st instar larvae of the oriental tobacco budworm, Helicoverpa assulta. Though there was a variation in the insecticidal efficacy among transgenic lines, T9 and T12 lines exhibited more than 95% mortality at 7 days after feeding treatment. These results suggest that CpBV-CST1 is a useful genetic resource to be used to generate GM crop against insect pests.