• The Plant Pathology Journal
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• v.32 no.3
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• pp.201-208
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• 2016

The main areas for field-grown vegetable production in Iran were surveyed during the years of 2012-2014 to determine the occurrence of begomoviruses infecting these crops. A total of 787 leaf samples were collected from vegetables and some other host plants showing virus-like symptoms and tested by an enzymelinked immunosorbent assay (ELISA) using polyclonal antibodies produced against Tomato yellow leaf curl virus (TYLCV). According to the ELISA results, 81 samples (10.3%) positively reacted with the virus antibodies. Begomovirus infections were confirmed by polymerase chain reaction (PCR) using previously described TYLCV-specific primer pair TYLCV-Sar/TYLCV-Isr or universal primer pair Begomo-F/Begomo-R. The PCR tests using the primer pair TYLCV-Sar/TYLCV-Isr resulted in the amplification of the expected fragments of ca. 0.67-kb in size for ELISA-positive samples tested from alfalfa, pepper, spinach and tomato plants, confirming the presence of TYLCV. For one melon sample, having a week reaction in ELISA and no reaction in PCR using TYLCV-specific primers, the PCR reaction using the primer pair Begomo-F/Begomo-R resulted in the amplification fragments of the expected size of ca. 2.8 kb. The nucleotide sequences of the DNA amplicons derived from the isolate, Kz-Me198, were determined and compared with other sequences available in GenBank. BLASTN analysis confirmed the begomovirus infection of the sample and showed 99% identities with Tomato leaf curl New Delhi virus (ToLCNDV); phylogenetic analysis supported the results of the database searches. This study reports the natural occurrence of TYLCV in different hosts in Iran. Our results also reveal the emergence of ToLCNDV in Iranian cucurbit crops.

• The Plant Pathology Journal
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• v.32 no.5
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• pp.377-387
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• 2016

Tomato yellow leaf curl virus (TYLCV), a member of the genus Begomovirus, is one of the most important viruses of cultivated tomatoes worldwide, mainly causing yellowing and curling of leaves with stunting in plants. TYLCV causes severe problems in sub-tropical and tropical countries, as well as in Korea. However, the mechanism of TYLCV infection remains unclear, although the function of each viral component has been identified. TYLCV C4 codes for a small protein involved in various cellular functions, including symptom determination, gene silencing, viral movement, and induction of the plant defense response. In this study, through yeast-two hybrid screenings, we identified TYLCV C4-interacting host proteins from both healthy and symptom-exhibiting tomato tissues, to determine the role of TYLCV C4 proteins in the infection processes. Comparative analyses of 28 proteins from healthy tissues and 36 from infected tissues showing interactions with TYLCV C4 indicated that TYLCV C4 mainly interacts with host proteins involved in translation, ubiquitination, and plant defense, and most interacting proteins differed between the two tissues but belong to similar molecular functional categories. Four proteins-two ribosomal proteins, S-adenosyl-L-homocysteine hydrolase, and 14-3-3 family protein-were detected in both tissues. Furthermore, the identified proteins in symptom-exhibiting tissues showed greater involvement in plant defenses. Some are key regulators, such as receptor-like kinases and pathogenesis-related proteins, of plant defenses. Thus, TYLCV C4 may contribute to the suppression of host defense during TYLCV infection and be involved in ubiquitination for viral infection.

• Research in Plant Disease
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• v.21 no.3
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• pp.180-185
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• 2015

In the present work, a pair of primers specific to Tomato yellow leaf curl virus (TYLCV) was designed to allow specific amplification of DNA fragments from any TYLCV isolates using an extensive alignment of the complete genome sequences of TYLCV isolates deposited in the GenBank database. A pair of primers which allows the specific amplification of tomato ${\beta}$-tubulin gene was also analyzed as an internal PCR control. A duplex PCR method with the developed primer sets showed that TYLCV could be directly detected from the leaf crude sap of infected tomato plants. In addition, our developed duplex PCR method could determine PCR errors for TYLCV diagnosis, suggesting that this duplex PCR method with the primer sets is a good tool for specific and sensitive TYLCV diagnosis. The developed duplex PCR method was further verified from tomato samples collected from some farms in Korea, suggesting that this developed PCR method is a simple and reliable tool for rapid and large-scale TYLCV detections in tomato plants.

• Korean Journal of Agricultural Science
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• v.46 no.3
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• pp.507-517
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• 2019

To follow up on a 2017 survey of tomato virus diseases, samples with virus-like symptoms were collected from the same areas (Buyeo-gun, Chungchungnam-Do and Daejeon, Korea) in 2018. While in 2017 mixed infections of Tomato mosaic virus with either Tomato yellow leaf curl virus (TYLCV) or Tomato chlorosis virus were detected, only TYLCV was detected in symptomatic samples in 2018. TYLCV amplicons of c.777 bp representing the coat protein (CP) coding region were cloned from the TYLCV positive samples, and the sequence data showed a 97.17% to 98.84% nucleotide and 98.45% to 99.22% amino acid identity with the 2017 Buyeo-gun isolate (MG787542), which had the highest amino acid (aa) sequence identity of up to 99.2% with four 2018 Buyeo-gun sequences (MK521830, MK521833, MK521834, and MK521835). The lowest aa sequence identity of 98.45% was found in a 2018 Daejeon isolate (MK521836); the distance between Buyeo-gun and Daejeon is about 45 km. Phylogenetic analysis indicated that the currently reported CP sequences are most closely related to Korean sequences from Masan (HM130912), Goseong (JN680149), Busan (GQ141873), Boseong (GU325634), and the 2017 isolate TYLCV-N (MG787543) in the 'Japan' cluster of TYLCV isolates and distinct from the 'China' cluster isolates from Nonsan (GU325632), Jeonju (HM130913) and Jeju (GU325633, HM130914). Our survey data from 2017 and 2018 suggest that TYLCV has become established in Korea and may be spread by whitefly vectors from weed reservoirs within the farm environment.

• Research in Plant Disease
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• v.28 no.1
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• pp.39-45
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• 2022

Patterns of occurrence of tomato yellow leaf curl virus (TYLCV) and tomato chlorosis virus (ToCV) with whitefly on summer-cultivated tomato in Gwangju-si, Gyeonggi Province were surveyed using multiplex reverse transcription-polymerase chain reaction in 2020. In addition, distribution of the whiteflies species and their viral transmission rates were investigated throughout the tomato growing season. The infection rates of TYLCV and ToCV increased sharply during harvest, and the single infection rates were 30.9% and 5.0%, respectively, with a mixed infection rate of the two viruses being the highest at 52.2%. Single infection with TYLCV and double infections with TYLCV and ToCV accounted for the majority with 83.1%. Bemisia tabaci were dominant over Trialeurodes vaporariorum in greenhouse grown plants, and all of the investigated B. tabaci biotypes were identified as Mediterranean (MED, formerly known as Q biotype). The transmission rate of TYLCV, detected in every sampled B. tabaci MED population, was 21.4%, and the mixed transmission rate with ToCV was 35.5%. Viruliferous MED whiteflies with ToCV showed a higher rate than that of T. vaporariorum. In the transplant stage, viruliferous rate of both TYLCV and ToCV of B. tabaci was 42.7%; this rate was highest in the harvest stage. In examination of tomato yield, the increase in the mixed infection rate of TYLCV and ToCV led to complete yield loss. When the mixed infection rate increased by 10%, the yield decreased by 405.4 kg/10a.

• Research in Plant Disease
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• v.15 no.1
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• pp.1-7
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• 2009

Viruses diagnosed on crops including rice plants from farmers or agricultural extension agencies cover the country were 11 species including Broad bean wilt virus 2 (BBWV2) in 2008. Tomato spotted wilt virus (TSWV) was the most important virus having the detection rate of 22.9%. Two viruses of Tomato yellow leaf curl virus (TYLCV) and Tobacco leaf curl virus (TLCV) inducing leaf yellow and curl diseases on tomatoes were occurred newly with the detection rate of 12.2% and 4.0%, respectively, in 2008. Rice stripe virus (RSV) was occurred on 869.5 ha mainly at Jindo and Haenam areas in Jeollanamdo province. At Jindo area, 12 plots were damaged severely with the infected hill rate of 83.8%. At the main production area of oriental melon at Seongju, almost all fruits from whole sale market at Seongju were infected with Cucumber green mottle mosaic virus (CGMMV) as the detection rate of 87%. The areas occurred TSWV in Korea were 25 totally from 2003 including 7 areas newly reported in 2008 including Naju in Jeoallanamdo. TSWV could be reduced as 0.1 % from 5.3% by covering insect proof net in vinyl house after chemical soil sterilization. Tomato yellow leaf curl disease was occurred on April in 2008 at Tongyoung area in Kyeongsangnamdo, and detected continuously at 13 areas, 7 in Kyeongsangnamdo, 4 in Jeollabukdo and 2 in Jejudo. Potato spindle tuber viroid (PSTVd) was occurred abruptly in a confined space of a civil breeding greenhouse and a cultivar evaluation field followed by disuse 17.4 M/T of potato tubers. No PSTVd was detected at 17 fields cultivated the related potatoes to the bred company by RT-PCR.

• Horticultural Science & Technology
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• v.29 no.4
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• pp.336-344
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• 2011

Using the abundant available information about the tomato genome, we developed DNA markers that are linked to disease resistant loci and performed marker-assisted selection (MAS) to construct multi-disease resistant lines and varieties. Resistance markers of Ty-1, T2, and I2, which are linked to disease resistance to Tomato yellow leaf curl virus (TYLCV), Tomato mosaic virus (ToMV), and Fusarium wilt, respectively, were developed in a co-dominant fashion. DNA sequences near the resistance loci of TYLCV, ToMV, and Fusarium wilt were used for primer design. Reported candidate markers for powdery mildew-resistance were screened and the 32.5Cla marker was selected. All four markers (Ty-1, T2, I2, and 32.5Cla) were converted to cleavage amplification polymorphisms (CAPS) markers. Then, the CAPS markers were applied to 96 tomato lines to determine the phenetic relationships among the lines. This information yielded clusters of breeding lines illustrating the distribution of resistant and susceptible characters among lines. These data were utilized further in a MAS program for several generations, and a total of ten varieties and ten inbred lines were constructed. Among four traits, three were introduced to develop varieties and breeding lines through the MAS program; several cultivars possessed up to seven disease resistant traits. These resistant trait-related markers that were developed for the tomato MAS program could be used to select early stage seedlings, saving time and cost, and to construct multi-disease resistant lines and varieties.

• Research in Plant Disease
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• v.22 no.4
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• pp.297-302
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• 2016

Tomato yellow leaf curl virus (TYLCV) is a viral disease causing severe economic losses on tomato. Practical prevention of the TYLCV disease is to control tabacco whitefly (Bemisia tabaci) or to cultivate TYLCV-resistant tomato cultivars, because no agrochemical products are available to control TYLCV. In this study, TYLCV resistance of the commercial tomato cultivars were evaluated using the DNA markers tightly linked to TYLCV resistance genes Ty-1 and Ty-3 and infection with the TYLCV clones mediated by Agrobacterium. In marker genotyping, resistance alleles were detected from 4 oval type tomato cultivars (Titichal, TY tinny, TY saengsaeng II, TY sense Q). Four cheery type cultiavrs (TY endorphin, TY smartsama, Tiara TY, Olleh TY) and 6 round type cultivars (TY kingdom, TY ace, TY homerun, TY altorang, Dotaerang TY winner, Styx TY). The seedling bioassay indicated that tomato cultivars of the oval type and cherry type showed consistancy in marker genotype and phenotype while slight disease symptom was observed from some round type cultivras (TY ace, TY homerun, Styx TY) with resistance marker genotype. For fruit yields, TY tinny was greater than its control cultivar Titichal in oval types, TY smartsama was greater than its control Smile in cherry type, and TY ace and TY kingdom were greater than their control Dabok. These cutliavrs can be a good choice for high-yielding TYLCV-resistant tomato cultivars.

• Research in Plant Disease
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• v.28 no.2
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• pp.82-91
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• 2022

Recently, several in vitro studies have reported antiviral activity of agents of systemic acquired resistance against plant virus infection, but the approach has not been applied in a wide range of agricultural fields. The objective of this study was to evaluate the inhibitory effect of the exogenous application of salicylic acid (SA), chitosan (CH), or eugenol (EG) in tomato yellow leaf curl virus (TYLCV) infection of greenhouse-grown tomato plants. In vitro, the initial time of symptom was observed in TYLCV-infected plants (VP) of the resistant cultivar 'Superdotaerang' at 12 days post inoculation (dpi) after application of antiviral agents. At 32 dpi, the disease rate of TYLCV in the CHT+VP (0.1% chitosan and virus infected control) treated plants was 87.5%, lower than that of the other treatment. However, the virus content in the CHT+VP treated plants was higher than those of the other treatments, and SA, EG, and CH did not show significant effect on plant height or shoot and root fresh weight. Our results from summer-cultivated greenhouse-grown tomatoes show that none of the tested agents had an inhibitory activity on viral infection or yield of tomato 'Dotaerangsola'cultivar. In contrast, all treated 'TY Giants' cultivars that possessed TYLCV resistance genes Ty-1 and Ty-3a did not show typical symptoms and the virus content was remarkably lower than those in the TYLCV treated plants in 'Superdotaerang'. The results of this research indicated that the planting of resistant tomato cultivars was effective method instead of using SA, EG, and CH (known as resistance-inducing factors for control) of TYLCV in the field.

• Korean journal of applied entomology
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• v.51 no.4
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• pp.377-382
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• 2012

This study investigated the occurrence of sweet potato whitefly, Bemisia tabaci affecting cucumber, eggplant and red pepper, as well as sweet potato species, and its response to insecticides in Gyeonggi province from 2010 to 2011. Sweet potato whitefly is widespread throughout the southern part of Gyeonggi province. Most regional populations of B. tabaci belong to biotype Q having been reported in the south Korea since 2005, but in Goyang mixed populations of two biotypes (B and Q) were found. Survey results of Tomato Yellow Leaf Curl Virus (TYLCV) disease that was vectored by B. tabaci indicated that this virus disease was not spread throughout the Gyeonggi province. Biotype Q of B. tabaci was found to be resistant to neonicotinoid insecticides, whereas biotype B was highly susceptible to them.