Lettuce Mosaic Virus Research Articles

Lettuce Mosaic Virus in Lettuce Production Areas in Finike District of Antalya Province

Bu çalışmada, Antalya ili Finike ilçesi marul üretim alanlarında Marul mozaik virüsü (Lettuce mosaic virüs: LMV)’nün belirlenmesi amacıyla yürütülmüştür. Virüsün tanılama çalışmalarında DAS-ELISA (Double Antibody Sandwich Enzyme Linked Immunosorbent Assay) ve IC-RT-PCR (Immunocapture Ters Transkripsiyon Polimeraz Zincir Reaksiyonu) yöntemleri kullanılmıştır. Bu amaçla araştırma alanından 92 marul örneği toplanmıştır. Örnekler LMV etmenine spesifik antibadiler kullanılarak DAS-ELISA testine tabi tutulmuştur. DAS-ELISA yöntemine göre; 5 örnek LMV ile enfekteli bulunmuştur. DAS-ELISA testinde pozitif çıkan 5 örnek IC-RT-PCR çalışmalarında kullanılmıştır. IC-RT-PCR çalışmalarında, LMV’ye özgü primer çiftleri (1196, 1087) kullanılmış ve LMV’nin 800 bp’lik bir kısmı çoğaltılarak agaroz jel elektroforezinde beklenen seviyede bant elde edilmiştir. Bu çalışma ile Antalya ili Finike ilçesinde LMV’nin varlığı ilk kez ortaya konulmuştur.

Konya İli Marul Ekim Alanlarında Sorun Olan Virüs Hastalıklarının Belirlenmesi

Lettuce (Lactuca sativa L.) is a member of the family Compositae (Asteraceae). This plant, which is grown for its leaves, is grown in open field and greenhouse conditions almost everywhere in the world and in Turkey. With the present study virus diseases of lettuce and their prevalence in Konya province was revealed for the first time. For this purpose, leaf samples were taken from lettuce plants showing virus diseases symptoms with surveys carried out in Konya province lettuce planting areas from May to August in 2020. Then the collected lettuce leaf samples were tested in laboratory conditions by Double Antibody Sandwich Enzyme-linked Immunosorbent Assay (DAS-ELISA) method to reveal infections of Cucumber mosaic virus (CMV), Miraflori lettuce big vein virus (MiLBVV), Lettuce mosaic virus (LMV), and Tomato spotted wilt virus (TSWV). According to the information obtained from the results of the study, it was determined that 40 out of 97 (41.23%) lettuce plant samples and all (6) weed samples were infected with at least one of the viruses. In lettuce leaf samples; TSWV (27.83%), LMV (12.37%), CMV (10.31%) and MiLBVV (5.15%) infections have been detected. In weed samples; infections of CMV (83.33%), LMV (66.66%), and TSWV (50%) have been revealed. The infections of TSWV, LMV, CMV, and MiLBVV on lettuce plants in Konya province were reported firstly with the study.

In-Field Evaluation of Drone-Released Lacewings for Aphid Control in California Organic Lettuce.

Aphids are one of the most economically important pests to California's Central Coast lettuce industry. Aphids vector the lettuce mosaic virus and are crop contaminants in the packaging of the product. Lettuce aphid, Nasonovia ribisnigri (Mosley) (Hemiptera: Aphididae), is one of the predominant aphid species in lettuce, and it poses unique management challenges forming colonies inside the lettuce head. Current management practices rely on repeated foliar insecticide applications to reduce aphid densities per plant. Some organic growers have explored the release of laboratory-reared beneficial insects to manage aphids in their commercial fields. This project sought to document the effects of drone-released lacewing eggs on lettuce aphid densities in organic romaine lettuce fields. Commercially reared lacewing eggs were released at a rate of 74,131 eggs/ha and organic-certified insecticides were sprayed following their respective label recommendations. Our results could be interpreted as preliminary evidence that drone release of lacewings could reduce aphid densities (15.6-150.0 aphids/lettuce head) when compared to the untreated plots (32.1-257.9 aphids/lettuce head). Aphid densities were also decreased after the application of foliar organic-certified insecticides (11.77-143.5). Traditionally, the cost of labor has limited the use of beneficials in the lettuce production system, but the use of drones for these releases may make this strategy more attractive. Based on our calculations, spraying an organic-certified insecticide is less expensive (direct operational costs of U.S. $ 116.36/ha) than releasing beneficial insects by hand ($ 185.40) or by drone ($ 176.00) when mimicking the conditions of this study.

Detection and characterization of Lettuce mosaic virus (LMV) in Adana and Mersin provinces in Turkey

Amaç: Bu çalışma 2015-2019 yılları arasında sonbahar ve kış aylarında Adana (Ceyhan, Çukurova, Karaisalı, Sarıçam, Seyhan, Yumurtalık ve Yüreğir ilçeleri ile Yakapınar mahallesi) ve Mersin (Tarsus ilçesi ile Yenice mahallesi) illerinde yaygın olarak marul yetiştiriciliğinin yapıldığı alanlarda marul mozaik virüsü (Lettuce mosaic virus, LMV)’nün saptanması ve karakterizasyonu amacıyla yürütülmüştür.Yöntem ve Bulgular: Arazi çıkışlarında simptomatolojik olarak LMV ile enfekteli olduğundan şüphelenilen toplam 180 adet marul bitkisinden örnekleme yapılmış ve toplanan örnekler öncelikle Double Antibody Sandwich ELISA (DAS-ELISA) yöntemi ile testlenmiştir. Toplam 26 örnekte LMV’nin varlığı saptanmıştır. LMV’ye spesifik primer çifti (1196;1087) kullanılarak yapılan RT-PCR çalışmalarında ise, 24 örnek LMV ile enfekteli bulunmuş ve 800 bp büyüklüğünde band elde edilmiştir. Bunlar arasından seçilen 5 LMV izolatı ile yapılan sekans analizleri sonucunda, Adana ve Mersin izolatları dünyanın diğer ülkelerinden rapor edilen LMV izolatları ile %91.48-98.69 arasında benzerlik göstermiştir.Genel Yorum: Bu çalışmada Adana ve Mersin illerinde marul yetiştirilen alanlarda LMV’ninsurveyi yapılmış ve araştırılan örneklerde varlığı ortaya konulmuştur.Çalışmanın Önemi ve Etkisi: Bu çalışma ile birçok ülkede yetiştirilen sebzeler arasında ilk sıralarda yer alan marullarda hastalık oluşturan önemli virüslerden biri olan LMV’nin varlığı serolojik ve moleküler yöntemlerle ortaya konulmuş ve moleküler olarak karakterizasyonu başarıyla yapılmıştır.

Complete genome sequence and genome organization of scorzonera virus A (SCoVA), a novel member of the genus Potyvirus.

The complete genomic sequence of scorzonera virus A (SCoVA) from a Scorzonera austriaca Willd. plant in South Korea was determined by high-throughput sequencing and confirmed by Sanger sequencing. The SCoVA genome contains 9867 nucleotides, excluding the 3'-terminal poly(A) tail. The SCoVA genome structure is typical of potyviruses and contains a single open reading frame encoding a large putative polyprotein of 3168 amino acids. Pairwise comparison analysis of the complete genome and polyprotein sequences of SCoVA with those of other potyviruses showed that they shared the highest nucleotide and amino acid sequences identity (54.47% and 49.57%, respectively) with those of lettuce mosaic virus (GenBank accession number KJ161185). Phylogenetic analysis of the amino acid sequence of the polyprotein confirmed that SCoVA belongs to the genus Potyvirus. These findings suggest that SCoVA should be considered a novel member of the genus Potyvirus, family Potyviridae.

Phylogenetic and Population Analysis of Lettuce mosaic virus Isolates Based on the Coat Protein Gene

Lettuce mosaic virus (LMV) is one of the most important and destructive members of Potyviruses in the family Potyviridae that is transmitted by aphid and seed which cause economic damage and serious yield losses to different crops around the world. To explore phylogenetic relationships, population evolution, and the effect of selection forces on the complete coat protein (CP) gene of LMV isolates, 36 complete coat protein gene sequences retrieved from the GenBank database in several different countries in four continents: Central and East Asia (China, Taiwan, South Korea, and Turkey), Europe (France), Africa (Tunisia), and America (Chile and Brazil). The phylogenetic tree of LMV isolates was grouped into independent clades with the significance of FST values (>0.27). The ratio of dN/dS is calculated less than one and showed that the LMV-CP has been under negative selection. Statistical tests (Tajima’s D, Fu and Li’s D* and F*) were used to estimate non-significantly negative values for all clades and geographic populations except for the Brazilian population and Clade III in a phylogenetic group. The negatives values revealed that there is less polymorphism estimation. All geographic populations in four phylogroups of LMV seem to be at equilibrium because all neutrality test statistics were non-significant. The findings suggested that the dynamics of LMV molecular evolution may be dependent on mutation, recombination, and negative selection. No recombination events were observed in this part of the LMV genome. Therefore, this study provides the first time evolution and differentiation between populations of LMV isolates from around the world and suggested that they may be occurred by the transmission of the virus among lettuce plants by types of aphid species, migration in different geographical areas by infected seeds and plant material, and broad host range which seems that these events have played an important role in shaping the LMV population structure.

Complete genome sequence of a novel potyvirus isolated from Polygonatum kingianum.

The complete genome sequence of a putative novel potyvirus, tentatively named "Polygonatum kingianum virus 1" (PKgV1), infecting Polygonatum kingianum in China was determined (GenBank accession no. MK427056). PKgV1 has a genome organization that is typical of potyviruses, with a single large open reading frame (nt 123-9236) that encodes a 3037-aa polyprotein that is predicted to be cleaved into 10 mature proteins by virus-encoded proteases. Nine cleavage sites and several conserved motifs were identified in PKgV1 by comparative sequence analysis. Pairwise comparisons revealed that the PKgV1 polyprotein shares 52.0-56.2% nucleotide and 49.2-52.8% amino acid sequence identity with members of the genus Potyvirus. Phylogenetic analysis indicated that PKgV1 clustered with members of the genus Potyvirus and that it is closely related to but distinct from lettuce mosaic virus (LMV, accession no. KJ161186). These results suggest that Polygonatum kingianum virus 1 (PKgV1) is a new member of the genus Potyvirus of the family Potyviridae.

Poison hemlock virus Y (PHVY), a novel potyvirus from Iranian Conium maculatum (Apiaceae)

Poison hemlock (Conium maculatum L., Apiaceae) is native to temperate regions of Europe, West Asia and North Africa. During the 2015–2016 growing season, leaf samples of C. maculatum with mild mosaic and vein yellowing symptoms were collected from fields and pastures in the Bardsir region of Kerman Province (south-east Iran). The virions of one isolate of the virus, which we have named Poison Hemlock Virus Y (PHVY), were shown to be serologically related to potyviruses in ACP-ELISA tests using potyvirus-specific antibodies. Eight other viruses were not detected serologically in any samples. Mechanical transmission assays showed that the virus has a limited host range. Of the 12 test plant species mechanically inoculated, Chenopodium amaranticolor and three species of Apiaceae became infected. Groups of 10 Aphis gossypii or Myzus persicae given short-feeds on PHVY infected plants infected 20% and 15%, respectively, of test plants. The molecular weight of the viral coat protein (CP) was estimated by two methods to be 31 kDa. Electron microscopy showed that the partially purified virions were flexuous filaments c. 755 × 13 nm in size. Total RNA that was extracted from virus infected samples, and amplified in RT-PCR, gave three fragments, corresponding to the partial CI, HC-Pro and genomic 3′ terminal regions. The CP region of PHVY has the largest shared nucleotide (72.9%) and encoded amino acid (68.0%) identities with those of Lettuce mosaic virus. We conclude that PHVY is novel Potyvirus of the family Potyviridae.

Prisustvo i molekularna karakterizacija virusa mozaika krastavca u usevu šafranike u Srbiji

Safflower (Carthamus tinctorius L.) is an important oilseed crop belonging to the family Asteraceae. A total of 46 safflower samples were collected from Srbobran locality (South Backa District) in Serbia in 2015 and analysed for the presence of cucumber mosaic virus (CMV), alfalfa mosaic virus (AMV), and lettuce mosaic virus (LMV), using commercial double-antibody sandwich (DAS)-ELISA kits. Both viruses, CMV and AMV, were detected serologically in the collected samples. None of the analysed samples was found to be positive for LMV. The presence of CMV was further confirmed by mechanical transmission to test the plants including Chenopodium quinoa, C. amaranticolor, Nicotiana glutinosa, and Datura stramonium as well as C. tinctorius, confirming the infectious nature of the disease. Molecular detection of CMV was performed by amplification of a 871 bp fragment in all the tested samples, using the specific primers CMVCPfwd/CMVCPrev that amplify the entire coat protein (CP) gene and part of 3'and 5'-UTRs of CMV RNA 3. The RT-PCR products derived from the isolates 290Saff and 294Saff were sequenced (MH577791 and MH577792, respectively) and compared with the CMV sequences available in GenBank. Phylogenetic analysis based on CP gene sequences showed clustering of the selected isolates into three subgroups: IA, IB and II. Serbian CMV isolates found in safflower belong to subgroup II. To our knowledge, this is the first report on CMV infection of safflower in Serbia, which has the potential to cause substantial damage to safflower production and pose a threat to other economic crops grown in Serbia.

First Report of Lettuce Mosaic Virus Infecting Pea in Taiwan

First Report of Lettuce Mosaic Virus Infecting Pea in Taiwan

Detection of Lettuce mosaic virus infection in South Marmara Region of Turkey and coat protein gene characterization

Detection of Lettuce mosaic virus infection in South Marmara Region of Turkey and coat protein gene characterization

Growth stage‐dependent resistance to the potyviruses lettuce Italian necrotic virus and Lettuce mosaic virus displayed by Lactuca sativa introgression lines carrying the Mo3 locus from L. virosa

The single dominant gene Mo3 from accession PIVT1398 of Lactuca virosa was shown previously to confer resistance to all tested isolates of Lettuce mosaic virus (LMV; genus Potyvirus), including mo1‐resistance‐breaking isolates. Because accession PIVT1398 is also resistant to the recently described potyvirus lettuce Italian necrotic virus (LINV), this study checked whether the Mo3 resistance locus could be involved in resistance to LINV. Introgression lines of Mo3 into two different L. sativa genetic backgrounds (Girelle and Mantilia) were resistant to isolates LMV‐9, LMV‐13 and LINV‐Fr (a French isolate of LINV), whereas Girelle and Mantilia were susceptible to these virus isolates. The resistance reaction in inoculated leaves of the introgression lines varied from absence of symptoms and absence of virus detection for LMV‐9, to hypersensitive‐like necrotic lesions and low virus titres for LINV‐Fr and large necrotic lesions and relatively abundant virus detection for LMV‐13. At the systemic level, the resistance phenotype was growth stage‐dependent for LINV‐Fr and LMV‐13. Inoculation of ≥28‐days‐old plants led to absence of symptoms and no virus with the three tested potyvirus isolates in almost all plants. Inoculation of younger plants (≤22‐days‐old) led to chlorotic/necrotic lesions on some apical leaves with low virus titre in a varying proportion of plants with LINV‐Fr and on all plants with efficient virus detection with LMV‐13. These results show that the Mo3 gene, or a tightly linked locus, in L. virosa PIVT1398 controls resistance to LINV in addition to LMV and could be used to breed L. sativa cultivars with broad‐spectrum potyvirus resistance.

Viruses infecting periwinkle ( Catharanthus roseus L.) in Western Saudi Arabia

Periwinkle ( Catharanthus roseus L.) is an ornamental plant widely grown in the Mecca region in the Kingdom of Saudi Arabia (KSA). Different symptoms similar to those induced by viruses (mosaic, vein clearing, mottling, yellowing, flower variegation) prompted surveys in eight different regions of KSA to assess the presence of periwinkle-infecting viruses, i.e. Tomato spotted wilt virus (TSWV), Cucumber mosaic virus (CMV), Lettuce mosaic virus (LMV), Catharanthus mosaic virus (CatMV) and Catharanthus yellow mosaic virus (CYMV). Two hundred and forty leaf samples were collected from naturally infected nurseries, gardens and landscape plantings, and tested by DAS-ELISA, RT-PCR and PCR assays. Results showed that all five viruses were present in the surveyed areas, with incidence of infection reaching 58%. TSWV was the most widespread, found in 44% of samples, followed by CYMV (35%), whereas CatMV (15%), CMV (11%) and LMV (6%) were present to lesser extents. The virus incidence ranged between 43% in Rabigh to 77% in Taif. This is the first report of CYMV and CatMV in KSA, and of TSWV, LMV and CMV in periwinkle in western Saudi Arabia. The high incidence of viruses and of multiple infections in periwinkle plants endangers this crop in KSA, so a sanitation programme for eliminating virus infections is desirable.

Markers for Rapid Evaluation of Virus Resistance for TYLCV in Tomato, ZYMV and PRSV-W in Zucchini and LMV in Lettuce and Hybrid Seeds in Pumpkin

Screening for the source of virus resistance in horticultural plants or specific characterization as hybridization, through symptoms, requires time and depends on the weather and knowledge of plant characteristics. So, it is important to develop specific gene markers to allow rapid diagnosis by PCR. Markers were developed based on sequences homology comparison of susceptible and resistant plants provided by HORTEC SEEDS in tomato for Tomato yellow leaf curl virus (TYLCV) by the resistance gene Ty-1, in zucchini for Zucchini yellow mosaic virus (ZYMV) and Papaya ringspot virus estirpe watermelon (PRSV-W), and in lettuce for Lettuce mosaic virus (LMV). Fragments of 249 bp were amplified only by resistant plants to TYLCV as the hybrids 2648 and Aguamiel, and not for varieties as Santa Cruz or Carina. It were observed for ZYMV the amplification of 791 bp by the resistant hybrid Px7051 and not for the susceptible cultivar La Belle; for PRSV-W using the same zucchini plants the amplification of 650 bp for susceptible and 750 bp for resistant; for LMV the 421 bp amplification only for the resistant cultivar Brasil 303 and not for susceptible Baba de Verao. Finally, it was observed that primers PK47F/R were able to check the Cabotia seed hybrids of pumpkin Jabras.

Genetic Variability of Multifunctional HC-Pro Gene of <I>Lettuce mosaic virus</I> in Northern Region of India

Genetic Variability of Multifunctional HC-Pro Gene of <I>Lettuce mosaic virus</I> in Northern Region of India

The Potyvirus Particle Recruits the Plant Translation Initiation Factor eIF4E by Means of the VPg covalently Linked to the Viral RNA.

The viral protein genome-linked (VPg) of potyviruses is a protein covalently linked to the 5' end of viral RNA. It interacts with eIF4E, a component of the cellular translation initiation complex. It has been suggested that the 5' RNA-linked VPg could mimic the cellular mRNA cap, promoting synthesis of viral proteins. Here, we report evidence for recruitment of the plant eIF4E by Lettuce mosaic virus (LMV, potyvirus) particles via the 5' RNA-linked VPg. Analysis of the viral population was performed by enzyme-linked immunosorbent assay-based tests, either with crude extracts of LMV-infected tissues or purified viral particles. In both cases, LMV-VPg and LMV-eIF4E subpopulations could be detected. After reaching a maximum within the first 2 weeks postinoculation, these populations decreased and very few labeled particles were found later than 3 weeks postinoculation. The central domain of VPg (CD-VPg) was found to be exposed at the surface of the particles. Using a purified recombinant lettuce eIF4E and CD-VPg-specific antibodies, we demonstrate that the plant factor binds to the VPg via its central domain. Moreover, the plant eIF4E factor could be imaged at one end of the particles purified from LMV plant extracts, by immunoredox atomic force microscopy coupled to scanning electrochemical microscopy. We discuss the biological significance of these results.

Identification of host factors potentially involved in RTM-mediated resistance during potyvirus long distance movement

The long distance movement of potyviruses is a poorly understood step of the viral cycle. Only factors inhibiting this process, referred to as "Restricted TEV Movement" (RTM), have been identified in Arabidopsis thaliana. On the virus side, the potyvirus coat protein (CP) displays determinants required for long-distance movement and for RTM-based resistance breaking. However, the potyvirus CP was previously shown not to interact with the RTM proteins. We undertook the identification of Arabidopsis factors which directly interact with either the RTM proteins or the CP of lettuce mosaic virus (LMV). An Arabidopsis cDNA library generated from companion cells was screened with LMV CP and RTM proteins using the yeast two-hybrid system. Fourteen interacting proteins were identified. Two of them were shown to interact with CP and the RTM proteins suggesting that a multiprotein complex could be formed between the RTM proteins and virions or viral ribonucleoprotein complexes. Co-localization experiments in Nicotiana benthamiana showed that most of the viral and cellular protein pairs co-localized at the periphery of chloroplasts which suggests a putative role for plastids in this process.

Inheritance and effectiveness of two transgenes determining PVY resistance in progeny from crossing independently transformed tobacco lines

Genetic transformation of plants allows us to obtain improved genotypes enriched with the desired traits. However, if transgenic lines were to be used in breeding programs the stability of inserted transgenes is essential. In the present study, we followed the inheritance of transgenes in hybrids originated from crossing two transgenic tobacco lines resistant to Potato virus Y (PVY): MN 944 LMV with the transgene containing Lettuce mosaic virus coat protein gene (LMV CP) and AC Gayed ROKY2 with PVY replicase gene (ROKY2). Progeny populations generated by successive self-pollination were analyzed with respect to the transgene segregation ratio and resistance to Potato virus Y in tests carried out under greenhouse conditions. The presence of the virus in inoculated plants was detected by DAS-ELISA method. The results demonstrated the Mendelian fashion of inheritance of transgenes which were segregated independently and stably. As a result, we obtained T4 generation of hybrid with both transgenes stacked and which was highly resistant to PVY.

Incidencia, severidad y detección de virus fitopatógenos en lechuga, en el estado de Querétaro, México

The present study evaluated incidence, severity, and viral frequency by means of ELISA of luteovirus , Beet western yellows virus (BWYV), Cucumovirus , cucumber mosaic virus (CMV), Potyvirus , lettuce mosaic virus (LMV), Alfamovirus , alfalfa mosaic virus (AMV), and tospovirus, Tomato spotted wilt virus (TSWV). Experimental randomized complete block design was used, with three replicate. Plus, a multiple comparison of means with Tukey P ≤ 0.05. Virus severity and incidence was different depending of the planting date and the locality. Second planting date, in Pedro Escobedo county, Qro., Mexico, presented the highest severity and incidence. BWYV, CMV, LMV, AMV and TSWV viruses were detected, at 9.8%, 23.6%, 0.9%, 2.2% and 9.3%, respectively.

Incidence of Lettuce mosaic virus in lettuce and its detection by polyclonal antibodies produced against recombinant coat protein expressed in Escherichia coli

Lettuce mosaic virus (LMV), a member of the genus Potyvirus of family Potyviridae, causes mosaic disease in lettuce has recently been identified in India. The virus is seed borne and secondary infection occurs through aphids. To ensure virus freedom in seeds it is important to develop diagnostic tools, for serological methods the production of polyclonal antibodies is a prerequisite. The coat protein (CP) gene of LMV was amplified, cloned and expressed using pET-28a vector in Escherichia coli BL21DE3 competent cells. The LMV CP was expressed as a fusion protein containing a fragment of the E. coli His tag. The LMV CP/His protein reacted positively with a commercial antiserum against LMV in an immunoblot assay. Polyclonal antibodies purified from serum of rabbits immunized with the fusion protein gave positive results when LMV infected lettuce (Lactuca sativa) was tested at 1:1000 dilution in PTA-ELISA. These were used for specific detection of LMV in screening lettuce accessions. The efficacy of the raised polyclonal antiserum was high and it can be utilized in quarantine and clean seed production.