Broad bean wilt virus 2 (BBWV2) is a species in the genus Fabavirus and family Secoviridae, which is transmitted by aphids and has a wide host range. The BBWV2 genome is composed of two single-stranded, positive-sense RNAs, RNA-1 and RNA-2. The representative symptoms of BBWV2 are mosaic, mottle, vein clearing, wilt, and stunting on leaves, and these symptoms cause economic damage to various crops. In 2019, Perilla fructescens leaves with mosaic and yellowing symptoms were found in Geumsan, South Korea. Reverse-transcription polymerase chain reaction (RTPCR) was performed with specific primers for 10 reported viruses, including BBWV2, to identify the causal virus, and the results were positive for BBWV2. To characterize a BBWV2 isolate (BBWV2-GS-PF) from symptomatic P. fructescens, genetic analysis and pathogenicity tests were performed. The complete genomic sequences of RNA-1 and RNA-2 of BBWV2-GS-PF were phylogenetically distant to the previously reported BBWV2 isolates, with relatively low nucleotide sequence similarities of 76-80%. In the pathogenicity test, unlike most BBWV2 isolates with mild mosaic or mosaic symptoms in peppers, the BBWV2-GS-PF isolate showed typical ring spot symptoms. Considering these results, the BBWV2-GS-PF isolate from P. fructescens could be classified as a new strain of BBWV2.

토마토반점위조바이러스 (TSWV)는 고추, 토마토 등 경제적으로 중요한 작물에 심각한 피해를 주는 바이러스들 중 한 종이다. TSWV의 넓은 기주범위, 매개충인 총채벌레 방제의 어려움 및 TSWV의 효과적인 치료제가 없기 때문에, 저항성 품종을 사용하는 것이 TSWV를 예방하는 가장 효과적인 수단이 될 수 있다. 본 연구에서는 토마토에서 분리된 TSWV 분리주 (SW-TO2)의 유전학적·생물학적 특성을 구명하고, 최근에 국내에서 분리된 구기자, 머위, 당귀 TSWV 분리주와 비교하였다. 순수분리된 SW-TO2는 28 종의 지표식물 중 토마토를 포함한 17종에서 원형반점, 모자이크 증상 등 전신감염 증상을 보였다. SW-TO2의 유전자 계통분석 결과 국내에서 분리된 고추, 구기자 TSWV 분 리주와 98~99%의 상동성을 보이며 같은 그룹에 속하였다. TSWV 저항성 평가를 위한 생물검정법을 확립하고, 시판되고 있는 고추와 토마토 품종을 대상으로 4종의 TSWV 분리주에 대한 저항성 평가를 검정하였다. TSWV 저항성 평가는 첫째, 접종엽에 괴사반점 증상이 나타나거나 병징이 없는 경우, 둘째, 상엽에 병징이 없는 경우, 셋째, 상엽을 RT-PCR 진단한 결과 음성이 나왔을 경우 등 3가지 조건이 다 충족될 때 저항성으로 평가하였다.

나리에 있어 Cucumber mosaic virus(CMV) 바이러스 저항 성 육종을 위해 주요 모본 및 부본으로 이용한 우수 유전자원 에 대해 바이러스 저항성 검정을 실시하였다. 바이러스 접종 원은 CMV-Taean으로 농업과학원에서 분양 받아 담배에 증식 하여 접종하였다. 바이러스 접종 식물체는 조직배양을 이용 하여 ‘Connecticut King’, ‘Party Diamond’, ‘Prato’, ‘Casa Blanca’, ‘Mona’, ‘Dublin’, ‘Rodrigo’, ‘Brunello’, ‘Avocado’ 품 종과 ‘FA08-17’ 계통에 대해 바이러스 무병주를 생산하여 실 험에 이용하였다. 바이러스 접종 효율을 높이기 위하여 접종 횟수를 1회와 2회로 나누어 실시하였으며 인산염 버퍼의 pH 를 6.9, 7.2, 7.5로 달리하여 접종하였다. 2회 접종, 인산염의 pH 6.9에서 접종 성공률이 높았다. ‘Casa Blanca’, ‘Avocado’ 품종의 잎에서 약한 모자이크와 노란색의 mottle 증상이 관측 되었으며 ‘Brunello’, ‘Rodrigo’, ‘FA08-17’에서 Hypersensitive response like 반응이 관찰되었다. ‘Brunello’, ‘Rodrigo’ 품종 에서 RT-PCR 검정 결과 바이러스가 검출되지 않았다. Reverse transcription-polymerase chain reaction(RT-PCR) 결과 바이 러스가 검출되었던 ‘Connecticut King’, ‘Prato’, ‘Casa Blanca’ 의 경우 Enzyme-linked immunosorbent assay(ELISA) 흡광도 가 낮게 나타났다. RT-PCR과 ELISA 검사 결과 잎과 구근에 서 CMV 검출이 다르게 나타남에 따라 나리에 있을 것으로 추측되며 바이러스 감염과 연관된 TOM1, OBE2, DND1 유 전자를 대상으로 발현 분석을 하였으나 유의한 결과를 얻지 못하였다.

The sweet potato whitefly, Bemisia tabaci (Gennadius, 1889) (Hemiptera: Aleyrodidae), is one of the most important agricultural pests by direct feeding and begomovirus transmission in the world. B. tabaci species complex consisting of about 30 species worldwidely has been mainly distinguished by molecular methods because of difficulties detecting morphological differences. In Korea, distribution of two exotic groups, the Mediterranean (Q biotype) and the Middle East-Asia Minor 1 (B biotype), were confirmed by comprehensive molecular methods in 2012. Of them, the Q biotype as a vector of Tomato yellow leaf curl virus (TYLCV) has caused significant crop yield losses. Tobacco leaf curl virus (TbLCV), one of four begomoviruses in Korea, was first reported in 2011. It damaged, although not frequent, to greenhouse tomatoes at Iksan, Gimje, Sunchang, and Jeju. The vector transmitting TbLCV, however, is not known yet. In this study, we sampled an unknown B. tabaci populations on leaves of the Japanese honeysuckle (Lonicera japonica) at Iksan in outdoor conditions. PCR analysis revealed that some populations were infected with TbLCV. We identified an unknown indigenous genetic group named as JpL and clarified its phylogenetic relationships based on nucleotide sequences of mitochondrial cytochrome oxidase I gene.

The small brown planthopper (SBPH), Laodelphax striatelleus (Fallén), is a insect vector of Rice stripe virus (RSV) in temperate countries such as Korea, Japan, China, and Taiwan. As SBPH is able to overwinter successfully in these areas, RSV disease in subsequent rice fields has been believed to be endemic. In Korea, however, the RSV disease outbreaks have been observed mainly but not continuously at some western regions since 2001, caused a severe damage to the rice production. Although many efforts are underway to explain the outbreak phenomenon, the exact related factors are not known yet. In the meantime of the study on SBPH population dynamics in 2009, we catched unusually large numbers of SBPH adults by aerial net traps, maximally over 900, in early June at western coastal counties such as Taean, Seocheon, Buan, Sinan, and Jindo in Korea. Age distribution changes of SBPH in winter and post-winter seasons at some selected fields shows that the adults might be not related to overwintering population. The adults of overwintering population emerged from early April. Newly hatched nymphs of first generation were found from mid-May. In late May, just before the unusual catch of adults, the developmental stages of SBPH were mostly below 5th instars. This means that the big adult populations would be results of mass migration of SBPH abroad. We present also spacial distribution and host relationship of overwintering population as well as viruliferous rate changes of immigratory population.