National Institutes of Agricultural Science

Suigen, South Korea

National Institutes of Agricultural Science

Suigen, South Korea
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Pusag J.C.A.,Kyungpook National University | Hemayet Jahan S.M.,Kyungpook National University | Lee K.-S.,National Institutes of Agricultural Science | Lee S.,Sungkyunkwan University | Lee K.-Y.,Kyungpook National University
Journal of Insect Physiology | Year: 2012

Acquisition of plant viruses has various effects on physiological mechanisms in vector insects. Bemisia tabaci is the only known vector of Tomato yellow leaf curl virus (TYLCV), which is a serious virus affecting tomato cultivars. In this study, the lifespan of Q1 biotype was compared between non-viruliferous (NV) and TYLCV-viruliferous (V) whiteflies. Total lifespan from egg to adult death of NV whiteflies was 62.54. days but 10.64. days shorter in V whiteflies. We investigated the temperature susceptibility of B. tabaci by comparing mortalities as well as heat shock protein (hsp) mRNA levels between NV and V whiteflies. For this, NV and V whiteflies were exposed for either 1 or 3. h at 4, 25, and 35. °C. The mortality of V whiteflies was higher than NV ones following exposure at either 4 or 35. °C, but there was no significant difference at 25. °C. Analysis of the expression level of heat shock protein (hsp) genes using quantitative real-time PCR showed that both cold and heat shock treatments stimulated higher expression of hsps (hsp40, hsp70, and hsp90) at various rates in V whiteflies than NV ones, but there was no difference at 25. °C. All together, our results show that TYLCV acquisition accelerated the developmental rate and increased susceptibility to thermal stress in B. tabaci. Therefore, this modification may result in reduced vector longevity due to increased metabolic energy utilization. Our results provide insights into the complex interaction between vector fitness and thermal stress in relation to the acquisition and transmission of plant viruses. © 2012 Elsevier Ltd.

Shim J.-K.,Kyungpook National University | Lee G.-S.,National Institutes of Agricultural Science | Lee S.,Sungkyunkwan University | Lee K.-Y.,Kyungpook National University
Journal of Asia-Pacific Entomology | Year: 2015

The sweetpotato whitefly, Bemisia tabaci, is a serious pest of various horticultural crops worldwide. Since 1990s, B. tabaci has been invaded into many countries due to climate change and global trades of agricultural products. Due to the rapid development of pesticide resistance, alternative techniques have been required for the control of B. tabaci. Here, we investigated whether oral ingestion of dsRNA induced knockdown in whiteflies. Double-stranded RNA (dsRNA) targeting heat shock protein 70 (hsp70) mRNA was produced from cDNA using specific primers. Adult whiteflies (less than 12 h post-eclosion) were allowed to ingest 20% (w/v) sucrose solution containing hsp70 dsRNA in a 2-layered membrane feeding tube. Individual whiteflies ingested 16.9 ng dsRNA on an average in 24 h Quantitative real-time PCR analysis showed that dsRNA ingestion decreased the mRNA level of hsp70 in a dose-dependent manner, and the hsp70 knockdown was sustained for at least 3 days. Furthermore, dsRNA-treated whiteflies showed increased mortality after 3 days of incubation at 25 °C. Mortality was prompted by heat shock but not by cold shock treatments. Our data suggest that the oral delivery of dsRNA had excellent efficacy for the RNAi treatment of whiteflies and that the expression of hsp70 was critical for the survival of B. tabaci, regardless of the temperature conditions. © 2015 Published by Elsevier B.V.

Park J.,Sungkyunkwan University | Kim S.,Sookmyung Womens University | Choi E.,Sungkyunkwan University | Kwak H.-R.,National Institutes of Agricultural Science | And 4 more authors.
Acta Virologica | Year: 2011

The complete DNA genome of sweet potato leaf curl virus (SPLCV) from samples obtained from eight regions was amplified by PCR and characterized in this study. The DNA genome of one group (SPLCV Korea group 1) consisted of 2828 nucleotides and that of the second group (SPLCV Korea group 2) consisted of 2829 nucleotides. Sequence comparisons showed that the genome sequences of SPLCV Korea isolates were closely related to those of SPLCV Brazil isolates (FJ969834, FJ969835, and FJ969836), SPLCV Japan isolate (AB433788), and SPLCV USA isolate (AF104036) with nucleotide sequence identity values ranging from 96-98%. Analysis of the phylogenetic relationship of SPLCV Korea isolates with other begomoviruses revealed that the majority of SPLCV Korea isolates were clustered with SPLCV Brazil isolates (FJ969834, FJ969835, and FJ969836). Recombination analysis results revealed three recombinations among SPLCV Korea isolates, SPLCV isolates from Brazil and Japan, and ipomoea yellow vein virus (IYVV) Italy isolate.

Park J.,Sungkyunkwan University | Jahan S.M.H.,Kyungpook National University | Song W.-G.,Kyungpook National University | Lee H.,Sungkyunkwan University | And 6 more authors.
Journal of Asia-Pacific Entomology | Year: 2012

Bemisia tabaci is a species complex that consists of at least 24 genetically diverse biotypes. Here, we determined the biotypes of 27 populations collected in 17 different regions of Korea. Nucleotide sequence comparisons of cytochrome oxidase showed that 26 populations were Q biotype and that one population, the Goyang population, was B biotype. Further subgroup analysis of the Q biotype showed that all populations belonged to the Q1 subgroup, which originates from Western Mediterranean countries. Five endosymbiotic bacteria from various B. tabaci populations were analyzed by comparing rDNA sequences. Hamiltonella was detected in all the populations tested regardless of biotype. Cardinium was detected in all Q biotype populations but not in the B biotype population, while Rickettsia was detected in the B biotype population but not in Q biotype populations. Arsenophonus and Wolbachia were detected in 35% and 58% of Q biotype populations, respectively, but not in the B biotype population. Our results show that the endosymbiont profile is strongly associated with each biotype and with subgroups of the Q biotype. Survey of TYLCV disease from 2008 to 2010 indicated that this disease is widely spread in Korea. This study suggests that the rapid spread of TYLCV may be associated with endosymbiont infection, particularly Hamiltonella infection of B. tabaci. © 2011 Korean Society of Applied Entomology, Taiwan Entomological Society and Malaysian Plant Protection Society.

Jahan S.M.H.,Kyungpook National University | Lee G.-S.,National Institutes of Agricultural Science | Lee S.,Sungkyunkwan University | Lee K.-Y.,Kyungpook National University
Journal of Asia-Pacific Entomology | Year: 2014

The light sensitivity of insects varies in response to different wavelengths of light. The change of light responses of vector insects plays an important role in the method of transmission and propagation of plant viruses. Here, we investigated whether the light attraction behaviors of whiteflies are altered by virus acquisition. Firstly, the light attraction rates of whiteflies were determined using LED light bulbs exhibiting different wavelengths in the visible and UV spectra. Whiteflies, Bemisia tabaci and Trialeurodes vaporariorum, were mostly attracted to green LEDs (526. nm). The attraction rate to green LED light was higher in B. tabaci than in T. vaporariorum, whereas it did not significantly differ between the B- and Q-biotypes of B. tabaci. Secondly, we investigated whether or not the green light attraction behavior of B. tabaci is influenced by the acquisition of Tomato yellow leaf curl virus (TYLCV). The attraction rate to green LED light was 2.5-3 times higher in TYLCV-infected whiteflies than in TYLCV-free whiteflies. However, this difference disappeared when the distance from the light source was greater than 0.5. m. Our results show that B. tabaci favors green light and its attraction is highly enhanced by the acquisition of the plant virus, TYLCV. © 2013.

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