• Korean Journal Plant Pathology
• /
• v.12 no.2
• /
• pp.187-190
• /
• 1996

백합으로부터 total RNA를 분리하여 LSV 외피단백질 유전자의 551 bp에 해당하는 특정 염기서열을 증폭할 수 있는 primer로 RT-PCR를 수행하였다. 그 결과 Lilium oriental hybrid cvs. Miani, Marco Polo, Casablanca, Le Reve 품종에서 551 bp의 DNA 절편이 증폭되었고 이 절편의 염기서열을 분석한 결과 LSV외피단백질 유전자의 일부임을 확인할 수 있었다. 그러므로 RT-PCR 방법으로, 실험에 사용하 s4품종 모두 LSV에 감염되어 있음을 알 수 있었다.

• Research in Plant Disease
• /
• v.26 no.4
• /
• pp.283-288
• /
• 2020

In September 2017, vein clearing and yellowing symptoms resembling those caused by viruses were observed on leaves of Malva verticillata in Chungnam, Korea. Nucleic acids were extracted from leaves of five symptomatic plants and tested by reverse transcription polymerase chain reaction using four virus specific primer pairs including malva vein clearing virus (MVCV). Amplicons of the expected size (600 bp) were obtained from total RNA of all samples using the MVCV-specific primers. To confirm the presence of MVCV in symptomatic plants, the DNA fragments from three samples were purified, and directly sequenced. BLAST analysis revealed that it shared the highest nucleotide identity (99%) with a MVCV isolate from tomato (Mexico). The virus isolates obtained from the third re-inoculated Chenopodium was designated as Cm1-5. Tissue from Cm1, Cm3, and Cm5 isolates was mechanically sap inoculated into 23 indicator plants. Cm3 isolate induced chlorotic local and mosaic symptoms in Althaea rosea. Phylogenetic analysis based on coat protein gene of 19 MVCV isolates from 6 different countries and plant species, did not correlated with either the geographical origin of the isolates, or pathogenicity. To our knowledge, this study first reports the natural occurrence of MVCV on M. verticillata in Korea and characterization of three Korean isolates of MVCV.

• Research in Plant Disease
• /
• v.24 no.1
• /
• pp.9-25
• /
• 2018

Plant viruses cause significant yield losses and continuously threaten crop production, representing a serious threat to global food security. Studies on plant-virus interactions have contributed to increase our knowledge on plant immunity mechanism, providing new strategies for crop improvement. The prophylactic managements consist mainly following international legislations, eradication of infected plants, and application of pesticide to decrease the population of vectors. Hence, putting together the pieces of knowledge related to molecular plant immunity to viruses is critical for the control of virus disease in fields. Over the last several decades, the outstanding outcomes of extensive research have been achieved on comprehension of plant immunity to viruses. Although most dominant R genes have been used as natural resistance genes, recessive resistance genes have been deployed in several crops as another efficient strategy to control viruses. In addition, RNA interference also regulates plant immunity and contribute a very efficient antiviral system at the nucleic acid level. This review aims at describing virus disease on crops and summarizes current resistance mechanisms. Furthermore, we will discuss the current biotechnological approaches to control viral diseases and the future questions that are to be addressed to secure crop production against viruses.

• Applied Biological Chemistry
• /
• v.39 no.5
• /
• pp.355-360
• /
• 1996

In vitro-tested ribozyme against synthesized cucumber mosaic virus (CMV) RNA (Agric. Chem. & Biotech. 37:56-63(1994)) was expressed in tobacco plant to develop virus resistant plants. The ribozyme sequence was linked to cauliflower mosaic virus 35S promoter and nopaline synthase(nos) terminator and this chimeric 35S-ribozyme-nos gene was sequenced. The sequenced chimeric gene was transferred to Agrobacterium tumefaciens LBA4404 using tri-parental mating system. The E. coli HB101 containing chimeric gene was incubated with E. coli HB101(pRK2073) as a helper and Agrobacterium tumefaciens LBA4404. Then Agrobacterium cells containing the ribozyme construct was cocultivated with tobacco leaf pieces. Ten different plants were regenerated from kanamycin containing MS medium. The presence of the ribozyme construct in the transgenic tobacco plants was confirmed by polymerase chain reaction (PCR). Seven different transgenic plants in ten different kanamycin resistant plants showed the expected size (570 base pairs) of 35S-ribozyme-nos gene fragment. Total RNAs were isolated from four different transgenic plants and separated on a 1% agarose gel containing formamide. Northern hybridization with 35S-ribozyme-nos gene fragment as a probe indicated that ribozyme transcripts may be degraded tv nuclease. Therefore, nuclease-resistant ribozymes are needed for the development of virus-resistant transgenic plants using ribozymes.

• Research in Plant Disease
• /
• v.14 no.1
• /
• pp.71-75
• /
• 2008

An isolate of Peanut stunt virus (PSV), named as Tr-PSV, was isolated from white clover (Trifolium repens L) showing mosaic symptom. Tr-PSV systemically infected all plants tested in the Nicotiana spp. and induced local lesions on inoculated leaves of Chenopodium amaranticolor. However, Tr-PSV induced typical mosaic symptoms as ER-PSV on Vigna unguiculata 5 to 6 days after inoculation, while Fny-CMV used as a control virus of Cucumovirus produced local lesions on inoculated leaves. In dsRNA analysis, Tr-PSV consisted of four dsRNAs, but satellite RNA was not detected. The cDNA of coat protein gene of Tr-PSV was amplified by RT-PCR using a Cucumovirus-specific single pair primers that designed to amplify a DNA fragment of approximately 950 bp. By restriction mapping analysis using RFLP of the RT-PCR products and by serological properties of gel diffusion test, Tr-PSV belongs to a typical member of PSV subgroup I. This is the first report on the occurrence of PSV in white clover in Korea.

• The Plant Pathology Journal
• /
• v.36 no.3
• /
• pp.280-288
• /
• 2020

RNA interference (RNAi) has attracted attention as a promising approach to control plant viruses in their insect vectors. In the present study, to suppress replication of the rice stripe virus (RSV) in its vector, Laodelphax striatellus, using RNAi, dsRNAs against L. striatellus genes that are strongly upregulated upon RSV infection were delivered through a rice leaf-mediated method. RNAi-based silencing of peroxiredoxin, cathepsin B, and cytochrome P450 resulted in significant down regulation of the NS3 gene of RSV, achieving a transcriptional reduction greater than 73.6% at a concentration of 100 ng/μl and, possibly compromising viral replication. L. striatellus genes might play crucial roles in the transmission of RSV; transcriptional silencing of these genes could suppress viral replication in L. striatellus. These results suggest effective RNAi-based approaches for controlling RSV and provide insight into RSV-L. striatellus interactions.

• The Plant Pathology Journal
• /
• v.38 no.4
• /
• pp.383-394
• /
• 2022

In Japan, the P1 protein (S-type) encoded by leek yellow stripe virus (LYSV) isolates detected in Honshu and southward is shorter than the P1 (N-type) of LYSV isolates from garlic grown in Hokkaido due to a large deletion in the N-terminal half. In garlic fields in Hokkaido, two types of LYSV isolate with N- and S-type P1s are sometimes found in mixed infections. In this study, we confirmed that N- and S-type P1 sequences were present in the same plant and that they belong to different evolutionary phylogenetic groups. To investigate how LYSV with S-type P1 (LYSV-S) could have invaded LYSV with N-type P1 (LYSV-N)-infected garlic, we examined wild Allium spp. plants in Hokkaido and found that LYSV was almost undetectable. On the other hand, in Honshu, LYSV-S was detected at a high frequency in Allium spp. other than garlic, suggesting that the LYSV-S can infect a wider host range of Allium spp. compared to LYSV-N. Because P1 proteins of potyviruses have been reported to promote RNA silencing suppressor (RSS) activity of HC-Pro proteins, we analyzed whether the same was true for P1 of LYSV. In onion, contrary to expectation, the P1 protein itself had RSS activity. Moreover, the RSS activity of S-type P1 was considerably stronger than that of N-type P1, suggesting that LYSV P1 may be able to enhance its RSS activity when the deletion is in the N-terminal half and that acquiring S-type P1 may have enabled LYSV to expand its host range.

• Korean Journal of Plant Resources
• /
• v.16 no.1
• /
• pp.82-88
• /
• 2003

Genomic RNA sequence of a tobamovirus infecting Eutrema wasabi plant(TMV-W) was determined. The RNA is composed 6,298 nucleotide and contains four OREs encoding the protein of 180KD(OREI), 130KD(ORE2),30KD(ORF3) and 18KD(coat protein, ORF4). ORE4, ORF 3, ORF 2 and ORF 1 are overlaped by 130, 20 and 40 nucleotides, and the overapping region can be folded into a stable hairpin styucture. This includes the 3'non-coding region of 238 nucleotides, coat protein gene(537 nucleotides,179 amino acid), 30KD movement protein gene(825 nucleotides, 275 amino acid), 13(IKD protein gene(1,896 nucleotides, 632 amino acid) and 180KD protein gene(2,958 nucleotides, 986 amino acid). The genomic RNA sequence was compared with homologous regions of eleven other tobamoviruses. TMV-WTE was similar to TMV-WSF(98.6%) in nucleotide sequence.

• The Plant Pathology Journal
• /
• v.33 no.5
• /
• pp.522-527
• /
• 2017

We determined the effects of atmospheric temperature ($10-30{\pm}2^{\circ}C$ in $5^{\circ}C$ increments) and carbon dioxide ($CO_2$) levels ($400{\pm}50ppm$, $540{\pm}50ppm$, and $940{\pm}50ppm$) on the infection of Solanum tuberosum cv. Chubaek by Potato leafroll virus (PLRV). Below $CO_2$ levels of $400{\pm}50ppm$, the PLRV infection rate and RNA content in plant tissues increased as the temperature increased to $20{\pm}2^{\circ}C$, but declined at higher temperatures. At high $CO_2$ levels ($940{\pm}50ppm$), more plants were infected by PLRV at $30{\pm}2^{\circ}C$ than at 20 or $25{\pm}2^{\circ}C$, whereas PLRV RNA content was unchanged in the $20-30{\pm}2^{\circ}C$ temperature range. The effects of atmospheric $CO_2$ concentration on the acquisition of PLRV by Myzus persicae and accumulation of PLRV RNA in plant tissues were investigated using a growth chamber at $20{\pm}2^{\circ}C$. The M. persicae PLRV RNA content slightly increased at elevated $CO_2$ levels ($940{\pm}50ppm$), but this increase was not statistically significant. Transmission rates of PLRV by Physalis floridana increased as $CO_2$ concentration increased. More PLRV RNA accumulated in potato plants maintained at 540 or $940{\pm}50ppm$ $CO_2$, than in plants maintained at $400{\pm}50ppm$. This is the first evidence of greater PLRV RNA accumulation and larger numbers of S. tuberosum plants infected by PLRV under conditions of combined high $CO_2$ levels ($940{\pm}50ppm$) and high temperature ($30{\pm}2^{\circ}C$).

• Research in Plant Disease
• /
• v.21 no.3
• /
• pp.186-192
• /
• 2015

Cucumber mosaic virus possesses 2b gene known as a suppressor of post-transcriptional gene silencing (PTGS). To investigate its function and effect in plant, transgenic Nicotiana benethamiana expressing 2b gene was developed and analyzed in phenotypic characteristics and differential gene expression (DEG) comparing with wild-type. Eight lines of transgenic plants ($T_0$) were obtained with difficulty and showed severe deformed phenotypes in leaves, flowers, petioles and etc. Moreover, transgenic plants were hardly able to set seeds, but small amounts of seeds were barely produced in some of transgene-hemizygous plants. DEG analysis showed that transgenic plant ectopically accumulated diverse RNA transcripts at higher levels than wild-type probably due to the disturbance in RNA metabolism, especially of RNA decay, caused by 2b-mediated inhibition of PTGS. These ectopic accumulations of RNAs disrupt protein and RNA homeostasis and then subsequently lead to abnormal phenotypes of transgenic plants.