• The Plant Pathology Journal
• /
• v.33 no.2
• /
• pp.206-211
• /
• 2017

The effect of temperature on the rate of systemic infection of potatoes (Solanum tuberosum L. cv. Chu-Baek) by Potato virus Y (PVY) was studied in growth chambers. Systemic infection of PVY was observed only within the temperature range of $16^{\circ}C$ to $32^{\circ}C$. Within this temperature range, the time required for a plant to become infected systemically decreased from 14 days at $20^{\circ}C$ to 5.7 days at $28^{\circ}C$. The estimated lower thermal threshold was $15.6^{\circ}C$ and the thermal constant was 65.6 degree days. A systemic infection model was constructed based on experimental data, using the infection rate (Lactin-2 model) and the infection distribution (three-parameter Weibull function) models, which accurately described the completion rate curves to systemic infection and the cumulative distributions obtained in the PVY-potato system, respectively. Therefore, this model was useful to predict the progress of systemic infections by PVY in potato plants, and to construct the epidemic models.

• Korean Journal Plant Pathology
• /
• v.2 no.1
• /
• pp.12-16
• /
• 1986

The reaction of seven cultivars of Nicotiana tabacum to eight naturally occurring strains of potato virus Y from tobacco and one from potato was determined by mechanical inoculations in greenhouse tests. Dixie Bright 244-2, McNair 3D, and Golden Stock Penish were highly tolerant to three mild strains, two from the United States and one from Korea, and to four severe strains, one each from the United States, West Germany, South Africa, and Korea. They also had some tolerance to a severe strain from Child and one from United States. Virus concentration in infected leaf tissue was virus strain-and cultivar-dependent.

• Journal of the Korean Society of Tobacco Science
• /
• v.20 no.1
• /
• pp.50-56
• /
• 1998

The complementary DNA (cDNA) of potato virus Y- vein necrosis strain (PVY-VN) replicase gene (Nlb) was transformed into tobacco (Nicotiana tabacum cv. Burley 21) plants. Out of 25 putative transformants regenerated, 3 were resistant to PVY-VN, one highly resistant plant with no symptom until seed harvest time and the other two with mild chlorotic spot symptoms at late stages after infection. No symptom was observed in the highly resistant plant, while mild vein necrotic symptoms were developed on suckers of the moderately resistant plants after seed harvest time, In the first generation (T1) via self fertilization, resistance to susceptibility frequency in transgenic plants from the highly resistant transformant was about 3 : 1, while it was lowered much (about 1:2 and 1:19) in T1 of the moderately resistant transformants. In the second generation (T2) of the highly resistant plant, resistance frequencies were similar to T1, but resistance levels varied greatly and appeared to be decreased. Key words : potato virus Y, viral replicate gene, transgenic tobacco plants, resistance.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.11 no.2
• /
• pp.89-95
• /
• 2006

Potato plants carrying the Ry gene are extremely resistance to a number of potyviruses, but it is not known which variety expressed the resistance. In this investigation, combined classical and molecular techniques were used to identify virus resistance potatoes. Mechanical inoculation of 32 varieties of Korean potato cultivars, with potato virus Y (PVY), induced various symptoms, such as mosaic, yellowing, necrosis, mottle, vein clearing and vein bending. Different virus spreading patterns were observed, such as highly sensitive, moderate and resistant to $PVY^o$ inoculated leaves in different cultivars. From the results of double antibody sandwich-enzyme links immunosorbant assays (DAS-ELISA), coupled with reverse transcription polymerase chain reaction (RT-PCR), Winter valley and Golden valley were found to be highly susceptible and resistant cultivars to $PVY^o$ respectively. TEM was used as a complementary method to conform the localization of the virus in leaf tissues. TEM detect virus particles in Golden valley, where, ELISA and RT-PCR were unable to detect the CP gene. However, the interior part of the tissues was severely deformed in $PVY^o$ infected Winter valley, than Golden valley The Ry gene is involved in an induced response in $PVY^o$ infected Golden valley plants. The methods described in this study could be applied for the screening and development of antiviral potatoes.

• Journal of the Korean Society of Tobacco Science
• /
• v.19 no.2
• /
• pp.117-123
• /
• 1997

Viral coat protein (CP) encoding cDNA with artificial start and stop codons was synthesized by reverse-transcriptase polymerase chain reaction (RT-PCR) from the Korean isolate of potato virus Y-vein nectrosis strain (pVY-VN). To make PVY CP cDNA to untranslatable form, three stop codons were inserted near the start codon by "megaprimer-PCR" method. The untranslatable CP cDNA was subcloned to plant expression vector and transferred to N. tabacum cv. NC82 by Agrobacterium-mediated transformation. Highly resistant plants to PVY infection were screened, based on symptom development after mechanical virus inoculation. By genomic PCR and Southern blot analysis, one or more copies of the untranslatable CP gene were found in all transformants. From northern blot analysis, highly resistant transgenic lines had very low level of CP transcript but susceptible lines had high level, suggesting resistance to PVY infection should be related to RNA-mediated mechanism.mechanism.

• Korean Journal Plant Pathology
• /
• v.3 no.4
• /
• pp.261-269
• /
• 1987

A virus which induced yellowing, vein banding and ruffling on pepper in the field was investigated. The virus reacted strongly with PVY - antiserum in ELISA, but not with antisera of cucumber mosaic virus, tobacco mosaic virus, tomato black ring virus, alfalfa mosaic virus, tomato spotted wilt virus, tobacco etch virus, pepper mottle virus, and tobacco ringspot virus. Electron micrographs revealed that the virus was a flexuous rod of 750-760nm in length. The virus was transmitted mechanically and by Myzus persicae in a nonpersistent manner. The host range was similar to that of PVY, except that Chenopodium amaranticolor and C. quinoa were infected systemiclly.

• The Plant Pathology Journal
• /
• v.32 no.4
• /
• pp.321-328
• /
• 2016

We examined the effects of temperature on acquisition of Potato virus Y-O (PVY-O), Potato virus A (PVA), and Potato leafroll virus (PLRV) by Myzus persicae by performing transmission tests with aphids that acquired each virus at different temperatures. Infection by PVY-O/PVA and PLRV increased with increasing plant temperature in Nicotiana benthamiana and Physalis floridana, respectively, after being transmitted by aphids that acquired them within a temperature range of $10-20^{\circ}C$. However, infection rates subsequently decreased. Direct qRT-PCR of RNA extracted from a single aphid showed that PLRV infection increased in the $10-20^{\circ}C$ range, but this trend also declined shortly thereafter. We examined the effect of temperature on establishment of virus infection. The greatest number of plants became infected when N. benthamiana was held at $20^{\circ}C$ after inoculation with PVY-O or PVA. The largest number of P. floridana plants became infected with PLRV when the plants were maintained at $25^{\circ}C$. PLRV levels were highest in P. floridana kept at $20-25^{\circ}C$. These results indicate that the optimum temperatures for proliferation of PVY-O/PVA and PLRV differed. Western blot analysis showed that accumulations of PVY-O and PVA coat proteins (CPs) were lower at $10^{\circ}C$ or $15^{\circ}C$ than at $20^{\circ}C$ during early infection. However, accumulation increased over time. At $25^{\circ}C$ or $30^{\circ}C$, the CPs of both viruses accumulated during early infection but disappeared as time passed. Our results suggest that symptom attenuation and reduction of PVY-O and PVA CP accumulation at higher temperatures appear to be attributable to increased RNA silencing.

• Proceedings of the Korean Society of Tobacco Science Conference
• /
• 2006.05a
• /
• pp.36-36
• /
• 2006

• Journal of the Korean Society of Tobacco Science
• /
• v.23 no.2
• /
• pp.123-132
• /
• 2001

In order to transform pokeweed antiviral protein cDNA to tobacco plant, total RNA was extracted from Phytolacca americana. PAP-II cDNA was synthesized from purified total RNA via RT-PCR and subcloned to recombinant vector pBluescript II SK-. 10 deletion mutant PAP-II cDNA fragments which were sequentially deleted from N-terminal by 90bp were synthesized from PAP-II cDNA except leading frame by PCR with primers designed in our laboratory. To select non-cytotoxic clone, pAc55M was constructed with yeast expression vector pAc55 and multicloning site(MCS). Sequentially deleted mutant PAP-II cDNAs were cloned on downstream of gall promoter of pAc55M. 6 non-cytotoxic deletion mutant PAP-II cDNA were selected. Selected cDNAs were cloned into plant expression vector pKGT101BH for transformation of these clones to plant through Agrobacterium tumefacience. After cloning, recombinant pKGT101BH carrying deleted mutant PAP-IIcDNA were transformed to Nicotiana tabacum cv. NC567. Transformed tobacco plants cultured on shooting and rooting media were transfered to green-house. About four weeks later, these plants were infected with physically infection using carborandum with PVY-VN strain. After 4 weeks, plants resistant to virus were selected , and seeds of these plants were gathered. Southern blot hybridization showed deleted fragments by 220bp and 420bp, so resistant ability of these plants is due to mutant PAP-II cDNA.

• Research in Plant Disease
• /
• v.9 no.1
• /
• pp.1-9
• /
• 2003

The occurrence of potato(Sotanum tuberosum) viral diseases caused by Potato virus X(PVX), Potato virus Y (PVY), Potato leafroll virus(PLRV), Potato vims S(PVS), Potato virus M(PVM), Potato virus A(PVA), Potato virus T(PVT), Alfalfa mosic virus(AIMV), Tobacco mosic virus(TMV), Potato mop top virus(PMTV) Tobacco rattle virus(TRV) and Potato spindle tuber viroid(PSTVd), potato witches' broom phytoplasma, have been identified so far in Korea. Major viral diseases such as PVX, PVY and PLRV had been studied more deeply, however, the others are just identified and only partially characterized since the first study on the relation between PVX nucleic acid and virus protein by Kim in 1961. The most studies on potato viral diseases are mainly focused on the problems of seed potato production. The National Alpine Agricultural Experiment Station(NAAES), since it began its activities in 1961, has given special attention to this problem by doing studies to identify, characterize and control potato virus diseases. This effort resulted in the development of new potato virus detection methods as a basis for elaborating new method of control, such as the production of seed potato free of virus and the selection of new virus-resistant transgenic potatoes. The further studies of potato viral diseases required would be fallowings: the continuous monitoring for the occurrence of identified or not identified potato viruses in Korea, the isolation of resistant viral genes, the development of control method for the non-persistently transmitted viruses like PVY, special vectors such as nematode and fungus transmitted viruses, TRV and PMTV and the development of control methods against potato viral diseases by viral cross protection, therapy, transgenic plant, and the use of the agents or molecules, such as virus inhibitors and antiviral proteins, etc., blocking viral replication.