• The Plant Pathology Journal
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• v.33 no.3
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• pp.307-317
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• 2017

Satsuma dwarf virus (SDV) or Citrus mosaic sadwavirus (CiMV) were not consistently detected in RTPCR assay with the primer sets based on gene of Japan isolates. SDV and CiMV isolates were distinctively divided into two groups based on phylogenetic analysis of PP2 gene cloned from 22 Korean isolates, and the Korean CiMV and SDV isolates shared 95.5-96.2% and 97.1-97.7% sequence identity with Japanese isolate, respectively. We developed PP2-1 primer set based on the PP2 gene sequence of Korean isolates to simultaneously and effectively detect SDV and CiMV. And CTLV-2013 and CTV-po primer sets were newly designed for detection of Citrus tatter leaf virus (CTLV) and Citrus tristeza virus (CTV), respectively. Using these primer sets, a new multiplex PCR assay was developed as a means to simultaneously detect 4 citrus viruses, CTV, CTLV, SDV, and CiMV. The degree of detection by the multiplex PCR were consistent with those of uniplex RT-PCR for detection of each of the viruses. Therefore, the new multiplex PCR provides an efficient method for detecting 4 citrus viruses, which will help diagnose many citrus plants at the same time. We verified that 35.2% and 72.1% of 775 trees in 155 orchards were infected with SDV or CiMV (SDV/CiMV) and CTV by the multiplex-PCR assay, respectively, and CTLV was not detected in any of the trees tested.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.123.1-123
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• 2003

The objective of this work was to analyze the population of sequence variants of citrus tristeza virus (CTV) isolates in Korea and to make the phylogeny trees of CTV in Korea. We also tried to analyze and find the mild strain of CTV to apply for the cross protection. The CTV isolates from yuzu (C. Junos) collected from different geographic areas of Southern provinces such as Namhae-Do, Kerche-Do, Bosung, Wan-Do and Koheung and Jeju-Bo, Korea were used for SSCP analysis. The SSCP profiles of the cDNAS obtained by RT-PCR with primers specifically designed for the p20 of the CTV population. The SSCP profiles obtained from 150 PCR products in yuzu contained two or three DNA bands, whereas, in some case, others contained four or more bands of similar intensity. The pathologically mild isolates of CTV usually yielded two DNA bands by SSCP profiles, whereas the SSCP profiles of the most virulent isolates contained more than two DNA bands. Plants shown severe stem pitting were corresponded to those plants with typical SSCP profiles of severe strains, and vice versa. This results indicate that the primers designed for SSCP analysis can be used for distinguishing the mild strains from severe strains of CTV.

• Horticultural Science & Technology
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• v.35 no.1
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• pp.121-130
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• 2017

This study was carried out to investigate a method for producing cultured virus - free ovules for breeding high - quality Citrus cultivars. Ovules from the immature fruits of three citrus cultivars native to Jeju (Dongjeongkyool, Cheongkyool, and Jikak) and two cultivars of Citrus unshiu Marc. (Miyagawa wase and Haryejosaeng) that were thought to be infected with Citrus tristeza virus (CTV) were cultured on MS2 medium (Murashige - Skoog [MS] basal medium containing $500mg{\cdot}L^{-1}$ malt extract, $50g{\cdot}L^{-1}$ sucrose, $1.0 mg{\cdot}L^{-1}$ kinetin, and $8g{\cdot}L^{-1}$ agar). After four weeks of culture, 10, 21, 13, 5, and 7 somatic embryos and 2, 4, 2, 4, and 5 white callus cells (surrounding green somatic embryos) were obtained from Dongjeongkyool, Cheongkyool, Jikak, Miyagawa wase, and Haryejosaeng, respectively. After six weeks of culture, somatic embryos were obtained from cultured cells grown on MT basal medium supplemented with malt extract ($500mg{\cdot}L^{-1}$), lactose ($70g{\cdot}L^{-1}$), and agar ($16g{\cdot}L^{-1}$). Over 60% of the somatic embryos from citrus cultivars native to Jeju developed into normal plants on MS basal medium supplemented with malt extract ($500mg{\cdot}L^{-1}$), sucrose ($50g{\cdot}L^{-1}$), and agar ($8g{\cdot}L^{-1}$) after 10 weeks of culture. Normal plants were regenerated from two Citrus unshiu Marc. cultivars on MT basal medium supplemented with sorbitol (1.0 M), galactose (1.0 M), $GA_3$ ($1.0mg{\cdot}L^{-1}$), and Gelrite ($3g{\cdot}L^{-1}$). The absence of virus in plants generated from cultured ovules was confirmed by RT - PCR and antigen - antibody reactions. Therefore, virus - free Citrus cells can be obtained for breeding high - quality citrus cultivars using the biotechnological technique evaluated in this study.

• Korean journal of applied entomology
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• v.18 no.2 s.39
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• pp.85-88
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• 1979

The cotton aphid, Aphis gossypii Glover, is known as the most important vectant vector of citrus tristeza virus, cucumber mosaic virus, potato virus Y and potato leafroll virus. This study conducted to investigate the life history of cotton aphid at Suweon, Korea$(Lat.37^{\circ}16'N,\;Long\;126^{\circ}59'E)$. The aphids were reared in small cages placed over twig of hibiscus and on the leaves of cucumber. The results obtained were summarized as follows: 1. Overwintering eggs hatched from mid to late April, with a hatching rate averaging seventy-nine percent. 2. The early-born progeny have 22 generations and the late-born progeny have 6 generations on hibiscus and cucumber from April to October. 3. The fundatrigeniae leave tile the primary host in late May to early June and migrate to the secondary hosts. 4. From early to mid Oct., the gynoparae migrate from the secondary hosts to the primary host. 5. The average length of life was about 29 days and they produced an average of 70 nymphs each. 6. The maximum number of aphids produced per female was 117 in the spring. 7. The developmental period ranged from 6 to 16 days (average 8 days), the reproductive period from 12.2 to 24.6 days (average 19 days). 8. The average number of nymphs produced by a female per dys was about 3.7, with a maximum number of 17.