토마토반점위조바이러스(TSWV)는 총채벌레가 매개하는 대표적인 바이러스로 고추 등 여러작물에서 심각 한 피해를 준다. 노지고추에서 토마토반점위조바이러스 발생 경감을 위한 총채벌레 방제시기를 설정하고자 시기별 총채벌레 발생량과 토마토반점위조바이러스병 발생량을 조사하였다. 2023년 전북 익산 노지 고추포장 에서 청색끈끈이트랩을 이용하여 총채벌레 발생량을 조사한 결과 4월 상순부터 채집되기 시작하여 5월 하순과 6월 하순에 발생최성기를 보였다. 반면 고추 꽃에서는 정식 2주후부터 꽃당 10마리 이상 관찰되었다. 토마토반점 위조바이러스병은 정식 30일 이후 증상이 발생하기 시작하여 빠르게 확산되는 경향이었다. 따라서 노지고추에 서 토마토반점위조바이러스병 경감을 위하여 총채벌레 방제를 활착 이후부터 시작하는 것이 좋을 것으로 판단 되었다.

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.

Thrips from the genus Frankliniella (Thysanoptera, Thripidae) are a serious insect pest of various crops, including vegetables, fruits and ornamental plants. Thrips cause significant economic damage plants directly by feeding, and indirectly by acting as vectors for the tospoviruses such as Tomato spotted wilt virus (TSWV) and Chrysanthemum stem necrosis virus (CSNV) in chrysanthemum. To investigate the associations of thrips with tospoviruses and their ability to transmit, we have developed a protocol for identifying tospovirus and thrips species simultaneously in an individual thrips sample was successfully conducted. Total RNA was extracted from thrips according to manufacturer’s insturctions of RNeasy mini kit (Quiagen co.), and then TSWV was identified by reverse transcription-polymerase chain reaction (RT-PCR) using TSWV specific primers for the N genes. The residual genomic DNA in thrips RNA extract was used as a template to identify thrips species by PCR using universal primers for ITS2 region and subsequently digesting the PCR product by an restriction enzyme (RsaI) In addition, a classification into the species of thrips was confirmed using the nucleotide sequence of PCR products. The developed protocol was applied to investigate the occurrence of viruliferous thrips species in thrips populations collected from chrysanthemum fields. In this study, most of thrips were identified to Frankliniella spp. and thirps that acquire TSWV was 14 % of 65 thrips.

Tomato spotted wilt virus (TSWV) causes one of the most destructive viral diseases that threaten tomato (Solanum lycopersicum) worldwide. So far, eight TSWV resistance genes, Sw1a, Sw1b, sw2, sw3, sw4, Sw-5b, Sw-6, and Sw-7 have been identified and Sw-5b has been incorporated into tomato for prevention of TSWV. The objectives of this research are first to discover single nucleotide polymorphisms (SNPs) in Sw-5 alleles and then to develop SNP markers to distinguish resistant genotypes against TSWV for marker-assisted breeding in tomato. First, DNA sequences of Sw-5b alleles from both resistant and susceptible cultivars amplified using known Sw-5 gene-based marker was analyzed. The single functional SNP (G→A) was detected as non-synonymous substitution because this SNP causes change of arginine (Arg599) to glutamine (Gln599). Next, the primer pair for high resolution melting analysis (HRM) was designed around this SNP. To determine accuracy of this SNP marker to distinguish resistant Sw-5b genotypes against TSWV, genotypes of 32 commercial tomato cultivars were checked. The newly developed SNP marker could select six cultivars carrying resistant Sw-5b genotype, which was 100% correlated with genotypes based on the gene-based marker. These results indicate that the SNP maker developed in this study could be useful for better tracking resistance to TSWV in tomato breeding.

Tsw, a single dominant resistant gene against Tomato spotted wilt virus (TSWV), has been mapped on chromosome 10 in Capsicum chinense species. Previously reported molecular markers linked to the Tsw gene are not transferable for all pepper breeding materials. To develop additional markers and do genome-based fine mapping of the Tsw gene, approaches of mapping comparison, pooled transcriptome analysis, and genome walking were applied. Eleven additional SNP molecular markers tightly linked to the Tsw gene were developed using tomato and pepper whole genome sequencing databases. Among them, four SNP markers, SNP7715-1, SNP68-1, SNP17918-1, and SNP1072-1, showed no recombination in two segregating populations of F2 ‘Telmo’ (210 individuals) and ‘SP’ (843 individuals). Three scaffold sequences from the C. annuum BAC database and two BAC clones from the BAC library of C. annuum ‘CM334’ covering the Tsw gene were identified by transcriptome analysis and genome walking. A pepper scaffold sequence covering three pepper scaffold sequences was identified from a final version of the C. annuum BAC database. The Tsw gene was delimited within 149 kb by alignment analysis of two BAC clone sequences and the pepper scaffold sequence. A total of 22 predicted genes were resided in the target region between SNP7715-1 and SNP1072-1 co-segregating markers. Among them, five predicted genes showing annotations of CC/TIR-NBS-LRR resistance proteins, mRNA-6, mRNA-7, mRNA-11, mRNA-12, and mRNA-13, were identified. The transcriptome analysis and gene expression study showed that the mRNA-13 was expressed in ‘PI152225’ but was absent in ‘Special’, demonstrating the mRNA-13 could be a strong candidate gene for the Tsw gene. This result will be favorable for cloning the Tsw gene and developing cultivars which carry the TSWV-resistance gene.

본 연구는 고온에 안정적인 TSWV 저항성 유전자원을 선발하기 위해 수행되었다. 우선, 저항성 검정조건을 마련하고자 8점의 TSWV 저항성 육성계통을 두 가지 온도 조건(주간 25℃ ± 3.1℃, 35℃ ± 2.2℃)에서 검정을 실시하였다. 8점 중 두 계통(11VR35와11VR51)은 25℃에서 이병율이 모두 0.0%이었으나 35℃에서는 각각 100%, 80%의 이병율을 보였다. 아울러11VR32 11VR47 11VR53 11VR54 는 25℃에서 이병율이28.6%, 37.5%, 10.0%, 10.0%를 보여 중도저항성으로 평가되었으나 35℃에서는 이병율이 모두 100%로 나타났다. 이러한 결과는 고온(30℃ 이상)에서 저항성이 변화한다는 기존 보고와 유사한 결과를 확인할 수 있었다. 따라서 TSWV저항성 검정은 고온에서 실시하는 것이 안정적이라고 판단되었다. 이러한 조건으로 저항성검정을 실시한 결과 5점의 TSWV 저항성 유전자원을 선발하였다. 5점의 TSWV 저항성 유전자원은 2 C.annuum (11PM25, 11PM28), 3 C.chinense (11FL34, 11FL38, 11FL44)이다. 그러나 이들은 Tsw에 의한 과민반응(hypersensitivity response; HR)과 같은 증상은 없었다. 따라서 5점의 TSWV 저항성 유전자원은 TSWV 저항성 품종육성에 새로운 저항성 재료로 사용될 것으로 기대된다.

Tsw, a single dominant resistant gene against Tomato spotted wilt virus (TSWV), has been mapped on chromosome 10 in Capsicum. Previously found molecular markers linked to the Tsw gene are not transferable for all pepper breeding materials. To develop segregating populations for the Tsw, commercial F1 cultivar C. annuum ‘Telmo’ was self-pollinated. An F2 population was obtained from the self-pollination of F1 plants deriving from a cross between C. annuum ‘Special’ and C. chinense ‘PI152225’. Twelve additional molecular markers linked to the Tsw gene were developed using tomato and pepper genome sequence database. A tomato scaffold sequence of 7841 kb in size covering the corresponding region of the Tsw locus was identified based on the sequence of Tsw-linked marker. Analyzing the tomato scaffold sequence, two sequences of pepper scaffold and contig at down and up site of the Tsw locus, respectively, were located. Three SNP markers linked to the Tsw locus (HRM1, HRM2, and HRM3) were developed using the pepper scaffold sequence of 419 kb in size. All three markers showed 2 recombinants (1.0 cM) out of 198 individuals of F2 ‘Telmo’ population. When analyzing these SNP markers in an F2 population deriving from C. annuum ‘Special’ and C. chinense ‘PI152225’, we detected 5 recombinants (0.76 cM) out of 659 individuals. HRM4, a SNP marker linked to the Tsw gene, was developed with a 99 kb pepper contig sequence. It showed 7 recombinants (3.5 cM) out of 198 individuals of F2 ‘Telmo’ population. We found 5 recombinants (0.76 cM) out of 659 individuals when HRM4 was analyzed in F2 population derived from C. annuum ‘Special’ and C. chinense ‘PI152225’. To narrow down the molecular markers linked to the Tsw locus, four SNP markers, HRM5, HRM6, HRM7, and HRM8, were developed with the pepper scaffold sequence. All of them showed 5 recombinants (0.76 cM) out of 659 individuals of F2 ‘SP’ population. Four other SNP markers, HRM9, HRM10, HRM11, and HRM12, were developed using the pepper contig sequence. HRM9 showed 5 recombinants (0.76 cM), HRM10 showed 4 recombinants (0.61 cM), and HRM11 and HRM12 showed 3 recombinants (0.46 cM) out of 659 individuals of F2 ‘SP’ population. The SNP markers developed in this study will be useful for fine mapping of the Tsw gene and for developing cultivars which carry TSWV-resistance gene.