• KOREAN JOURNAL OF CROP SCIENCE
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• v.63 no.3
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• pp.257-264
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• 2018

The recent global climate change induced the drought, flooding, and insect pest outbreaks. These caused the severe damage to crop yield in the domesticated field and occurrence change of insect pest species. The sap-sucking insect pest, aphids are common in soybean [Glycine max (L.) Merr.] and cause serious yield losses. Thus, developing resistance cultivars is promising and efficient strategy to prevent the significant yield losses by aphid and screening germplasm is the essential procedure to achieve this goal. We tried to establish a resistance test indicator for foxglove aphid, Aulacorthum solani (Kaltenbach), in soybean and found that plant damage degree or infested plant damage is most suitable one. Also we screened around 1,200 of soybean germplasm including wild and cultivated species for its resistance to foxglove aphid from the various origins, and 67 soybeans, including PI 366121, showed antixenosis resistance, 31 germplasms among 67 antixenosis germplasms were showed antibiosis to foxglove aphid with non-choice test. The identified foxglove aphid resistant soybean resources showed significantly low rate in survival test. Furthermore, resistance type, (i.e., antibiosis or antixenosis) of each candidate were varied. In this research, we established the screening index for foxglove aphid resistance in soybean, and identified the resistance varieties. This result could be useful resources in breeding for new foxglove aphid resistance soybean cultivars, and provide fundamental information to investigate the resistance mechanism in soybean.

• Journal of Microbiology and Biotechnology
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• v.26 no.3
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• pp.549-557
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• 2016

Aphids are a large group of hemipteran pests that affect the physiology, growth, and development of plants by using piercing mouthparts to consume fluids from the host. Based an recent data, aphids modulate the microbiomes of plants and thereby affect the overall outcome of the biological interaction. However, in a few reports, aboveground aphids manipulate the metabolism of the host and facilitate infestations by rhizosphere bacteria (rhizobacteria). In this study, we evaluated whether aphids alter the plant resistance that is mediated by the bacterial community of the root system. The rhizobacteria were affected by aphid infestation of pepper, and a large population of gram-positive bacteria was detected. Notably, Paenibacillus spp. were the unique gram-positive bacteria to respond to changes induced by the aphids. Paenibacillus polymyxa E681 was used as a rhizobacterium model to assess the recruitment of bacteria to the rhizosphere by the phloem-sucking of aphids and to test the effect of P. polymyxa on the susceptibility of plants to aphids. The root exudates secreted from peppers infested with aphids increased the growth rate of P. polymyxa E681. The application of P. polymyxa E681 to pepper roots promoted the colonization of aphids within 2 days of inoculation. Collectively, our results suggest that aphid infestation modulated the root exudation, which led to the recruitment of rhizobacteria that manipulated the resistance of peppers to aphids. In this study, new information is provided on how the infestation of insects is facilitated through insect-derived modulation of plant resistance with the attraction of gram-positive rhizobacteria.

• Journal of Forest and Environmental Science
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• v.31 no.4
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• pp.312-316
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• 2015

Rhizina undulata, the causal agent of Rhizina root rot, is a soil-borne fungus occurring on coniferous trees. The destruction of coastal forests caused by R. undulata infection has been mainly associated with bonfires at camping sites. However, Rhizina root rot was observed in the western coastal forests without fire. It was hypothesized that Rhizina root rot in this area might be closely related to the soil salinity, which can facilitate the growth and survival of R. undulata. So, the variation in sodium chloride (NaCl) resistance among isolates of Rhizina undulata was compared using liquid media containing different concentrations of NaCl ranging from 0 mM to 300 mM. Our results showed that, albeit of no growth at a higher concentration of NaCl (300 mM), most of R. undulata isolates were capable of germinating and grew at up to 100 mM, indicating that NaCl resistance varies among R. undulata isolates. It was further found that isolates from coastal areas seemed to be more tolerant to NaCl than those further away the coast. We demonstrated that R. undulata could be possible to survive in coastal areas, but was lower NaCl tolerance than other fungi.

• Korean journal of applied entomology
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• v.17 no.2 s.35
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• pp.75-80
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• 1978

The study was conducted to determine the inherited properties of the MEB resistance to natural population of the small brown plant-hopper(Laodelphax striatelluss). The plant-hoppers were collected from the natural population of Naju area where the highest insecticide resistance of MEF to the green rice leaf hopper (Nephotettix cincticeps) have been examined in 1976. And Naju collections were crossed to the susceptible Lab stock to examine the MEP resistance in the $F_1,\;BC_1F_1\;and\;F_2$ and $F_2$ populations. Ail the data were analyzed by the probit method. There was a difference in MEP resistance between Naju collection and susceptible Lab stock, showing $LD_{50}$ value of the former was 0.0029ug/insect compared to 0.0008ug/insect for the later. The $LD_{50}$ values and dosage-mortality lines of the $F_1$ and $BC_1F_1$ tended to close their resistant parent. and it was considered that the character of the MEP resistance in the Naju collection of the small brown plant hopper was controlled by the genetic traits. However, $LD_{50}$ value and dosasage-mortality lines of the $F_2$ populations were intermediate to their parents, it would be conclusive that the trait will be governed by a interaction of the genes or factors rather than the single genic control.

• Journal of The Korean Society of Grassland and Forage Science
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• v.31 no.2
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• pp.127-134
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• 2011

This experiment was carried out to know the adaptability and forage production and quality of corn hybrid for silage at paddy field of Chungnam region from 2008 to 2009. Among agronomic characteristics, 'Kangdaok' and 'Kwangpyongok' hybrid were somewhat strong for waterlogging and good stay green, lodging, disease and insect resistance. The dry matter yield of 'Kangdaok' and 'Kwangpyongok' hybrid were the highest among korean corn hybrids. Among introduced hybrid, 'P32T83' hybrid was strong for lodging and insect resistance, and had lower ear height and high Brix ($B^o$, %). The dry matter yield of 'P32T83' and 'P32P75' hybrid were 20,150 kg/ha and 20,500 kg/ha, respectively. The 'P32P75' hybrid was high as 73% in vitro dry matter digestibility (IVDMD) and good stay green. The result of this study indicated that 'Kangdaok', 'Kwangpyongok', 'P32T83' and 'P32P75' hybrid could be recommended as having good characters according to production, waterlogging tolerance, stay green, disease and insect resistance at paddy field in the middle region of Korea.

• Journal of Life Science
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• v.22 no.12
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• pp.1614-1620
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• 2012

Transgenic rice plants with increased resistance to rice brown planthopper (Nilaparvata lugens St${\aa}$l) were generated by particle bombardment-mediated transformation of plants with a gene encoding snowdrop lectin (Galanthus nivalis agglutinin; GNA) under control of the rice Rubisco small subunit (rbcS) promoter.. A large number of transgenic rice plants containing the GNA gene were generated. The integration, expression, and inheritance of this gene in the $R_1$ and $R_2$ generations were demonstrated by Southern and western blot analyses. The plants contained one to five copies of the transgene. The GNA protein comprised approximately 0.01-2.0% of total soluble protein in the $R_1$ and $R_2$ transgenic plants. Insect bioassays and feeding studies showed that the GNA protein expressed in the $R_2$ transgenic rice plants reduced the survival of brown planthoppers. The introduction of GNA into rice plants therefore can help to control insect pests.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.145-145
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• 2017

Foxglove aphid, Aulacorthum solani (Kaltenbach), is a Hemipteran insect that infected a wide variety of plants worldwide and caused serious yield losses in crops. The objective of this study was to identify the putative genes to foxglove aphid resistance in wild soybean, PI 366121 (Glycine soja Sieb. and Zucc.). One hundred and forty-one F4:8 recombinant inbred lines developed from a cross between susceptible variety, Williams 82 and foxglove aphid resistance wild soybean, PI 366121 were used. The two type of resistance response, antibiosis and antixenosis resistance were evaluated through choice and no-choice test, graded by the degree of total plant damage and primary infestation leaf damage; a genome-wide molecular linkage map was constructed with 29,898 single-nucleotide polymorphism markers utilizing a Axiom(R) 180K soyaSNP array. Using inclusive composite interval mapping analysis for foxglove aphid resistance, one major candidate QTL on chromosome 7 was identified. The major QTL on chromosome 7 showed both antixenosis and antibiosis resistance responses. The newly identified major QTL was consistent with previously reported QTL, Raso2, which showed around 5 times narrow down interval range with 8 candidate genes. Furthermore, total 1,115 soybean varieties including Glycine soja and Glycine max were exposed to germplasm screening, and 31 varieties, which showed significant antibiosis type foxglove aphid resistance were identified. This result could be useful in breeding for new foxglove aphid resistant soybean cultivars and developing novel insecticides.

• International Journal of Industrial Entomology and Biomaterials
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• v.19 no.2
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• pp.259-264
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• 2009

The AvChit gene encodes for a chitinase from the spider, Araneus ventricosus. This spider, A. ventricosus, is an abundant species in Korea. Arabidopsis thaliana plants were transformed with the AvChit gene using Agrobacterium tumefaciens. Thirteen transgenic lines expressing the AvChit gene were obtained. Functional expression of the AvChit gene in transgenic Arabidopsis was confirmed by Southern, northern and western blot analysis. The AvChit cDNA was expressed as a 61 kDa polypeptide in baculovirus-infected insect Sf9 cells. AvChit protein extracted from transgenic Arabidopsis exhibited high levels of chitinase activity. Phytopathological tests showed that two transgenic Arabidopsis lines expressing the AvChit gene displayed high levels of resistance to gray mold disease (Botrytis cinerea).

• Korean Journal of Environmental Agriculture
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• v.37 no.2
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• pp.125-134
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• 2018

BACKGROUND: Green peach aphid (Myzus persicae) is an insect pest that significantly affects crop production. A number of pesticides have been used for aphid control, but their concerns on insect resistance and food safety have required alternative methods for pest management. In an effort to find for an alternative approach to aphid control, we screened plants extracts and examined their potentiality as insecticidal bio-resources. METHODS AND RESULTS: Two hundred and ninety eight plant extracts were examined for insecticidal activity against the aphid, and the best candidate among them was chosen for further study. The extracts from Cinnamomum camphora was determined to be the best candidate exhibiting insecticidal activity more than 60% at a level of $1,000{\mu}g/mL$. GC/MS analyses detected camphor, borneol, 4-terpineol, ${\alpha}$-terpineol and caryophyllene oxide as major compositions from the extracts obtained by hydrodistillation. Caryophyllene oxide exhibited the highest insecticidal activity with a $LC_{50}$ value of $237{\mu}g/mL$. Camphor lowered significantly the $LC_{50}$ value of caryophyllene oxide and increased largely its concentration in aphid, suggesting that camphor played a role in enhancing the insecticidal activity of caryophyllene oxide. CONCLUSION: This study suggested that camphor and caryophyllene oxide may be used as an insecticidal bio-resource for insect control against green peach aphid.

• International Journal of Industrial Entomology and Biomaterials
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• v.2 no.1
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• pp.19-26
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• 2001

Transformed Spodoptera frugiperda (Sf9) cells expressing baculovirus very late factor (VLF-1) were constructed by using Autograha nuclear polyhedrosis virus (AcNPV) immediate earthy gene (ie1). Neomycin-resistance gene as a selectable marker was introduced under the control of AcNPV ie1 promoter, and Bombyx mori nuclear polyhedrosis (BmNPV-K1) vlf-1 gene was introduced under the control of the Drosophila heat shock protein gene (hspr70) promoter to yield dual expression plasmid with two independent transcription units. It was transfected into Sf9 cells and cell clones expressing vlf-1 were selected by G4l8 treatment. Genomic DNA from transformed cells was isolated and integration of AcNPV iel harboring vlf-1 was confirmed by PCR using AcNPV iel-specific primers and Southern blot analysis. The transformed cells expressing VLF-1 in an infection-independent manner expressed foreign gene product of recombinant baculovirus in the earlier stage of infection compared with control Sf9 cells. These results suggest the possible to develop highly efficient transformed insect cells for baculovirus expression vector system.