• Research in Plant Disease
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• v.20 no.4
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• pp.303-306
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• 2014

Tomato yellow leaf curl virus (TYLCV) disease survey of tomato plants cultivated at Youngam, Changseong and Hwasun in Jeonnam Province was conducted in 2012 to 2013. To detect TYLCV in the field, PCR assay was performed using genomic DNAs extracted from tomato samples. According to cropping pattern, 23 and 59.4% of TYLCV infections were shown in semi-forcing and retarding cropping systems, respectively, and the frequencies of diseased plants were 0.4 and and 13.1% in the two cropping systems, respectively. Especially, TYLCV incidences in the susceptible varieties were 24.3 and 83.0% in semi-forcing and retarding cropping systems, respectively. Resistant varieties showed 9.1% infection in retarding cropping system but did not in semi-forcing cropping system. Also, TYLCV was occurred on early June after transplanting on April and at approximate 20 days after transplanting on August or September.

• Journal of Plant Biotechnology
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• v.34 no.1
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• pp.55-59
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• 2007

The study was carried out to develop transformants resisting to Phyophthora blight disease in the domestic pepper cultivar Subicho. In transforming of syn600 promoter with elicitin gene using Agrobacterium (LBA4404/pBI101 syn600-syn${\alpha}$-elicitin) to cotyledons of pepper, rate of shoot formation in 'Subicho' was 11.1% in medium containing 3 mg/L zeatin and 0.05 mg/L NAA, and also 12.8% in medium containing combination of 4 mg/L zeatin and 0.05 mg/L MAA. For PCR reaction using elicitin gene primer of transformants regenerated from cotyledons, we detected a specific band of 536 bp, and also showed strong signal at position of 536 bp in accordance with NPTII gene used as probe in Southern blot. Transformants pepper shown resistance to blight fungus was inoculated to seedlings of the $T_{1}\;and\;T_{2}$ transformants by concentration (density: zoo spore $10^{3}/mL$).

• Journal of Plant Biotechnology
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• v.29 no.4
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• pp.287-293
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• 2002

We are trying to develop a transgenic carrot with aims of production and delivery of oral vaccine against microbial enteropathogen using a K88ac pilin gene. A K88ac antigen (pilin) gene was isolated by PCR from the K88ac genomic DNA. The pilin gene was constructed in pGA748 and introduced via Agrobacterium tumefaciens to the explants of carrot hypocotyl and then 494 transgenic lines were established. The amounts of the K88ac antigen produced in each of the cell lines were determined by western and two elite cell lines (M1-17, Y14-1) were selected based on higher levels of expression of the antigens as well as rate of cell growth and efficiency of embryogenesis. In order to test an immunization induced by oral administration of the transgenic carrot, serum of the mice fed with the carrot vaccine were tested in ELISA. It tumed out that the mice fed with 3 g of transgenic carrot showed a similar level of antibody compared to those applied with 10 $\mu\textrm{g}$ of the purified recombinant pilin protein. Besides, various clinical responses were measured after challenging with ETEC K88ac strain to the piglets experiencing an oral immunization with the transgenic carrot. The piglets fed with carrot vaccine showed a lower level of diarrhea in fecal score compared to those fed with non-transgenic carrot. A higher level of increase in weight of the piglets fed with the transgenic carrot vaccine was observed comparing to those fed with non-transgenic carrot as control.

• Research in Plant Disease
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• v.15 no.3
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• pp.170-174
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• 2009

In this paper, we report a characterization of Prunus necrotic ringspot virus (PNRSV) isolate. The virus was identified from 'Yumyeong' peach showing mild mosaic on leaves in commercial orchard of 'Umsung', Chungbuk province in Korea. The virus isolate produced ringspot symptom on the inoculated cotyledons and systemic mosaic and malformation on the upper leaves of Cucumis sativus. Systemic mottles were appeared in Chenopodium quinoa. When the buds of the virus infected stem were grafted on the healthy young Prunus persica GF305 seedlings, line pattern with mosaic appeared within 3 months. Isometric virus-like particles were found in parenchyma cells and plasmodesmata of C. sativus leaves inoculated mechanically with the virus. The cDNA fragments of PNRSV coat protein (CP) region, approximately 675bp, were synthesized from genomic RNA extracted from virus-infected leaves by RT-PCR using specific primer pairs. Partial nucleotide sequences of the CP regions were determined and analyzed with the known PNRSV. The CP gene of PNRSVKorea isolates showed 93.9~94.7% similarity to the 4 known PNRSV isolates.

• Journal of Plant Biotechnology
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• v.39 no.3
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• pp.196-204
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• 2012

This study was carried out to develop reliable systems for somatic embryogenesis in oil palm tree (Elaeis guineensis Jacq.), and to verify the somaclonal variants by RAPD analysis. Embryogenic callus was induced successfully on modified half-strength MS medium containing $NaH_2PO_4{\cdot}2H_2O$ and casein. Embryogenic callus was further developed to somatic embryo mass (SEM), which is very hard and bonded tightly each other. Plantlets were proliferated when SEM was cultured on modified MS medium containing half strength $NH_4NO_3$, casein and L-ascorbic acid. Plantlets were transplanted into pots containing artificial soils. When RAPD analysis was conducted using randomly selected 95 in vitro plantlets and 19 random primers, somaclonal variation was detected using BNR35 primer. There was missing band around 1 kb in #22, #28, #35, and #77 plantlets. In addition, bands obtained from #28, #35, and #77 was much stronger than other normal bands. The blast results at NCBI revealed that somaclonal variation observed in this study was related to chloroplast genome of oil palm. The results also revealed that oil palm reproduction system through somatic embryogenesis is quite reliable and early detection of somaclonal variants seem to be possible at in vitro stage by RAPD analysis.

• Korean Journal of Breeding Science
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• v.42 no.1
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• pp.50-55
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• 2010

The R-r:standard (R-r:std) allele of maize R gene complex consists of S subcomplex and P component; the S subcomplex regulates anthocyanin pigmentation of seed aleurone layer, and the P component confers pigmentation of the other plant parts. The S subcomplex contains two functional genes, S1 and S2 components. In the presence of Pl gene some alleles of R gene induce anthocyanin pigmentation of pericarp. In the present study, the effects of different R alleles on the anthocyanin pigmentation of pericarp in the presence of Pl gene were analyzed in order to identify the R gene component responsible for pericarp pigmentation. The results show that R-ch and r-ch alleles condition similar degrees of pericarp pigmentation, and that R-r:Ecuador (R-r:Ec) conditions stronger pigmentation. The r-ch allele, which is inferred that its S subcomplex has lost function but the P component is normal, induces pericarp pigmentation in the presence of Pl gene. On the contrary, the R-g:g1111 allele, derived from R-r:Ec and inferred that its S subcomplex functions normal but the P component has lost its function, did not induce pericarp pigmentation in the presence of Pl gene. Moreover, PCR analysis of genomic DNA's of R-ch and r-ch indicate that R-ch maintains both P and S1 components, whereas r-ch lacks for the S1 component. Taken together, The results suggest that the P components of R alleles inducing pericarp pigmentation in the presence of Pl gene are responsible for pericarp pigmentation.

• Research in Plant Disease
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• v.10 no.4
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• pp.241-247
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• 2004

Recently, we reported a satellite RNA (Paf-satRNA) which is encapsidated in a pepper isolate of Cucumber mosaic virus (CMV-Paf) regulated symptom attenuation of the helper virus. To characterize mild symptom domain of Paf-satRNA, a series of chimeric cDNAs of satRNAs were created by using full-length cDNA clones of Paf-satRNA and a Pep-satRNA, chlorosis-inducing satRNA in pepper plants, and analyzed for determinants of symptom attenuation. When compared the nucleotide sequences, the 3' and 5' terminal sequences of the two wild-type (wt) satRNAs contained relatively conserved sequences which are the typical to CMV satRNA. Ten bases insertions were found in PepY-satRNA, and two variable regions, 81st to 113th and 183rd to 265th from the 5'-end, were located in the middle parts of the satRNAs. To delineate the attenuated symptom-related domain for the Paf-satRNA, in vitro transcripts RNAs transcribed from the wt cDNAs and constructed chimeric cDNAs were combined with genomic RNAs, RNA1, RNA2 and RNA3, of CMV-Fny and inoculated onto Nicotiana benthamiana plants. These transcripts were fully infectious onto the N. benthamiana and infectivity was confirmed by the RT-PCR. Chimeric Paf(H/N)-satRNA and PepY(N/A)-satRNA as well as Paf-satRNA induced very mild mosaic or symptomless infection on N. benthamiana. By contrast, typical mosaic symptom and stunting of infected plants were induced when PepY-satRNA, PepY(H/N)-satRNA and Paf(N/A)-satRNA were infected to N. benthamiana. Paf-satRNA coinfected with CMV-Fny RNAs induced very mild to sympomless on pepper plants whereas PepY-satRNA-infected pepper expressed typical chlorosis mosaic symptom. Two kinds of chimeric mutants, Paf(H/N)-satRNA and PepY(N/A)-satRNA, induced mild mosaic or symptomless infection onto pepper plants, while PepY(H/N)-satRNA and Paf(N/A)-satRNA showed typical chlorosis and mosaic symptom with stunting. This results suggest that mild symptom-related domain for the Paf-satRNA was located on HpaI-NarI region.

• Research in Plant Disease
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• v.12 no.3
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• pp.298-302
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• 2006

An isolate of Cucumber mosaic virus(CMV), called as Can-CMV, was originally isolated from Canna generalis showing typical streak mosaic foliar symptoms, and its properties were investigated in this study. Whereas all known isolates of CMV could induce symptoms on their systemic hosts(four kinds of Nicotiana spp and a zucchini squash), Can-CMV induced no symptoms on its systemic hosts tested. Replication and movement of the virus on upper leaves as well as inoculated leaves-were confirmed by RT-PCR suggesting that Can-CMV could only infect systemically on N. benthamiana and N. glutinosa. Size of local lesions on the Can-CMV-inoculated leaves of Chenopodium amaranticolor was much smaller than that of Fny-CMV. Whereas Fny-CMV and LS-CMV could induce distinct necrotic local lesions on Vigna unguiculata 2 to 3 days postinoculation(dpi), chlorotic spots symptom was expressed by Can-CMV 4 to 5 dpi. Virus-specific 4 kinds of dsRNAs were isolated from leaves of N. benthamiana infected with Can-CMV, and these dsRNAs corresponded to the viral genomic RNAs and subgenomic RNAs and their patterns were indistinguishable to those of Fny-CMV and LS-CMV. By restriction mapping analysis of 950 bp of RT-PCR amplified products of coat protein gene of the virus as well as by serological analysis of gel diffusion test, Can-CMV belongs to a typical member of CMV subgroup IA. These results suggest that the Can-CMV isolated from C. generalis possesses unique pathological properties to understand further insight into the various interactions between virus and host.

• Korean Journal of Microbiology
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• v.40 no.4
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• pp.342-347
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• 2004

A bacterial strain YC4963 with antifungal activity against Colletotrichum orbiculare, a causal organism of cucumber anthracnose was isolated from the rhizosphere soil of Siegesbeckia pubescens Makino in Korea. Based on physiological and biochemical characteristics and 16S ribosomal DNA sequence analysis, the bac­terial strain was identified as Pseudomonas aurantiaca. The bacteria also inhibited mycelial growth of several plant fungal pathogens such as Botrytis cinerea, Fusarium oxysporum and Rhizoctonia solani on PDA and 0.1 TSA media. The antifungal activity was found from the culture filtrate of this isolate and the active compound was quantitatively bound to XAD adsorption resin. The antibiotic compound was purified and identified as phenazine-l-carboxylic acid on the basis of combined spectral and chemical analyses data. This is the first report on the production of phenazine-l-carboxylic acid by Pseudomonas aurantiaca.

• Research in Plant Disease
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• v.7 no.3
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• pp.155-163
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• 2001

Two attenuated Cucumber mosaic virus (CMV) isolates, Paf-CMV and Rs2-CMV that had been selected from CMV isolates associated with satellite RNA (satRNA) were tested for cross-protection effect in pepper plants. The viruses selected as attenuated strains appeared to be identical serologically and physically to the challenge virus (Mf-CMV), but they were lower in the dilution end-point of infectivity of crude sap than Mf-CMV When symptoms were observed in several indicator plants after inoculation, Paf-CMV and Rs2-CMV were symptomless or showed mild mosaic symptoms while another satRNA isolate Ap-CMV developed severe mosaic symptoms on the leaves as Mf-CMV. The nucleotide sequences of the satRNAs were determined by sequencing full-length cDNA clones. Paf-, Rs2- and Ap-satRNAs were 386, 335, and 347 nucleotides long, respectively, The sequences were then compared with the other known Y-satRNA, revealing that nucleotide sequences of the satRNAs consisted of 5'- and 3'-terminal conserved regions. However variations occurred on the middle regions of the sequences, especially those related to symptom interference, showing significant differences between Paf-satRNA and other isolates. Infectious transcripts of Paf-satRNA and Rs2-satRNA induced mild mosaic symptoms in pepper plants when supported by genomic RNAs of Mf-CMV. Under greenhouse conditions, Paf-CMV and Rs2-CMV were tested for cross-protection effect in pepper and tobacco (Nicotiana tabacum cv, Xanthi nc) plants against Mf-CMV. No symptoms were developed on the plants vaccinated with Paf-CMV until 3 weeks after inoculation with the virulent strain; however another attenuated isolate, Rs2-CMV, showed less effectiveness in cross-protection. Depending on the concentration of the challenged virus, symptoms sometimes appeared later in the upper leaves. However, in plants challenged with low concentrations (below 0.2 mg/ml) of the challenge inoculum, symptoms caused by the virulent strain did not develop on the plants vaccinated with Paf-CMV. In the field experiments, the number of pepper plants with severe mosaic symptoms in the control plots was progressively increased after transplanting and reached approximately 50% after 50 days. On the other hand, the incidence of mosaic disease appeared very low on the plants that had received the protective inoculation with Paf-CMV.