Strawberry Vein Banding Virus Research Articles

Polysaccharide peptide treatment eliminates strawberry viruses and promotes strawberry plant growth and rooting in tissue culture media.

Based on our previous finding that polysaccharide peptide (PSP) has substantial antiviral activity, we cultured strawberry plants infected with strawberry mild yellow edge virus (SMYEV) or strawberry vein banding virus (SVBV) in Murashige and Skoog (MS) media supplemented with PSP to test its ability to eliminate these viruses. PSP not only improved the elimination of SMYEV and SVBV but also promoted the growth and rooting of strawberry plants in tissue culture. On the 45th day, the average height of the 'Ningyu' strawberry plants in the 1 mg/mL PSP treatment group was 1.91 cm, whereas that of the plants in the control group was 1.51 cm. After the same time point, the number of new leaves on the tissue culture media supplemented with 1 mg/mL and 500 µg/mL PSP and without PSP were 4.92, 4.41, and 3.53, respectively. PSP also promoted strawberry rooting and significantly increased both the length and number of roots. In addition, after treatment with 1 mg/mL PSP treatment in tissue culture for 45 days followed by meristem-shoot-tip culture, the elimination rates of SMYEV and SVBV in regenerated 'Ningyu' strawberry plants ranged from 60% to 100%. This study investigated the use of the antiviral agent PSP for virus elimination. PSP has a low production cost and thus has great application potential for virus elimination in crop plants.

Strawberry Vein Banding Virus Movement Protein P1 Interacts With Light-Harvesting Complex II Type 1 Like of Fragaria vesca to Promote Viral Infection.

Chlorophyll a/b-binding protein of light-harvesting complex II type 1 like (LHC II-1L) is an essential component of photosynthesis, which mainly maintains the stability of the electron transport chain. However, how the LHC II-1L protein of Fragaria vesca (FvLHC II-1L) affects viral infection remains unclear. In this study, we demonstrated that the movement protein P1 of strawberry vein banding virus (SVBV P1) interacted with FvLHC II-1L in vivo and in vitro by bimolecular fluorescence complementation and pull-down assays. SVBV P1 was co-localized with FvLHC II-1L at the edge of epidermal cells of Nicotiana benthamiana leaves, and FvLHC II-1L protein expression was upregulated in SVBV-infected F. vesca. We also found that FvLHC II-1L effectively promoted SVBV P1 to compensate for the intercellular movement of movement-deficient potato virus X (PVXΔP25) and the systemic movement of movement-deficient cucumber mosaic virus (CMVΔMP). Transient overexpression of FvLHC II-1L and inoculation of an infectious clone of SVBV showed that the course of SVBV infection in F. vesca was accelerated. Collectively, the results showed that SVBV P1 protein can interact with FvLHC II-1L protein, which in turn promotes F. vesca infection by SVBV.

Development and evaluation of an isothermal recombinase polymerase amplification–lateral flow assay for rapid detection of strawberry vein banding virus in the field

The disease caused by strawberry vein banding virus (SVBV) is one of the main virus diseases affecting the growth and development of strawberries, and the development of an on-site method for rapid detection of SVBV would be useful for breeding virus-free strawberry seedlings. In this study, we used isothermal recombinant polymerase amplification (RPA) combined with lateral flow strip (LF strip) testing to achieve rapid diagnosis of SVBV following on-site rapid DNA extraction. The DNA target for the SVBV-RPA amplification was the specific nucleotide region, which is conserved between different SVBV isolates in China. This assay allowed detection of SVBV within 30 min, comprising rapid N3 DNA extraction for 10 min, DNA amplification with RPA for 15 min at 40 °C, and visualization of the amplicons by LF strip for 5 min. The conservative detection limit was as low as 10 pg DNA under optimized conditions. Furthermore, the diagnostic results obtained by SVBV-LF-RPA on-site for detection of suspected samples were consistent with those obtained by polymerase chain reaction (PCR), achieving the aim of highly sensitive on-site rapid diagnosis of most isolated SVBV strains. The system was successfully applied and validated for on-site detection of SVBV in the production of strawberry virus-free seedlings in Shanghai, demonstrating its suitability for on-site diagnosis of SVBV and high potential for application to SVBV detection nationwide.

Complete genome sequence of pueraria virus A, a new member of the genus Caulimovirus.

The complete genome sequence of a new caulimovirus in Pueraria montana was determined using high-throughput sequencing. The 7,572 nucleotide genome of pueraria virus A (PVA) contains genes that encode a movement protein, an aphid transmission factor, a virion-associated protein, a coat protein, a protease + reverse transcriptase + ribonuclease H, and a transactivator/viroplasmin protein, as well as two intergenic regions, which are all common features of members of the genus Caulimovirus. A sequence alignment revealed that the complete genome of PVA shares 66.82% nucleotide sequence identity with strawberry vein banding virus (GenBank accession no. KX249738.1). The results of phylogenetic analysis and the observation that the nucleotide sequence of the polymerase coding region differed by more than 20% indicated that PVA is a member of a new species the genus Caulimovirus, family Caulimoviridae.

Functional analysis of a viral promoter from a strawberry vein banding virus isolate from China

BackgroundPromoters are important factors affecting gene expression in cells. The driven activities of viral promoters were generally assessed to screen available promoters for transgenic and research and biotech industries. In this study, we cloned a full-length promoter from a Chinese isolate of strawberry vein banding virus (SVBV) and produced several deletion mutants for evaluation of applications in production of reporter proteins in stable transgenic plants.MethodsThe full-length promoter of SVBV (SP1) and its three deletion mutants (SP2, SP3, and SP4) were amplified using polymerase chain reaction. The effects of SVBV SP1, SP2, SP3, and SP4 on gene expression were evaluated using β-glucuronidase (GUS) and green fluorescent protein (GFP) reporter genes.ResultsTransient expression assays showed that the SVBV SP1 promoter and its three deletion mutants all expressed the reporter genes, albeit at very different levels. Interestingly, transcriptional activity driven by the SP1 promoter was much higher than that of the cauliflower mosaic virus (CaMV) 35S promoter. After stable transformation of the GUS gene into Nicotiana tabacum plants, SVBV SP1-driven transgene expression was approximately 2.6-fold higher than CaMV 35S promoter-driven transgene expression. In addition, GUS gene expression levels were enhanced by co-inoculation of the plants with the SP1 promoter-driven vector carrying the GUS gene and the vector expressing SVBV open reading frame (ORF) V or ORF VI.ConclusionsThe SVBV SP1 promoter from the Chinese isolate evaluated in this study could successfully drive transient and stable expression in plants, it was a stronger promoter than the CaMV 35S and FLt-US promoters and may be more useful for the production of stable transgenic plants.

Strawberry vein banding virus-based vector for transient overexpression in strawberry plants

Strawberry vein banding virus (SVBV) is a double-stranded DNA virus. In our previous studies, we generated an infectious clone of SVBV, pSVBV, which causes light-green vein banding symptoms along the leaf veins in strawberry plants (Fragaria vesca). In this study, we constructed pSVBV-P1-MCS and pSVBV-P4-MCS, two recombinant virus vectors containing a multiple cloning site (MCS) downstream of the SVBV-encoded movement protein gene (P1) and coat protein gene (P4), respectively. At 35 days post-inoculation, the two SVBV-based vectors could produce light-green vein banding symptoms on the systemic leaves of strawberry plants, indicating that they could successfully cause infection. Furthermore, the infectivity rates of the recombinant virus vectors pSVBV-P1-MCS and pSVBV-P4-MCS were similar to that of the wild-type infectious clone pSVBV, indicating that the insertion of MCS did not affect the infectivity of SVBV-based vectors. Additionally, we engineered SVBV as a transient overexpression vector, which could be used for the overexpression of exogenous green fluorescent protein in strawberry plants. Collectively, these SVBV-based vectors provide a new approach for the analysis of gene functions in strawberry plants.

Molecular characterization of strawberry vein banding virus from China and the development of loop\u2011mediated isothermal amplification assays for their detection

Strawberry vein banding virus (SVBV) is one of the serious viral pathogens infecting strawberry worldwide. To understand the molecular characterization of SVBV from China, complete genome sequences of sixteen SVBV isolates were cloned and sequenced. Sequence comparison showed they shared high nucleotide sequence identity (93.6–99.5%) with isolates from China and Japan (96.6–98.4%), while relatively low identity with the isolates from Canada (91.9–93.7%) and USA (85.5–85.9%). Phylogenetic analyses based on the complete genome sequence or coat protein (CP) gene showed the SVBV isolates clustered into three clades correlated with geographic distribution. Recombination analyses identified 13 recombinants and 21 recombinant events, indicating frequent and multiple recombinations in SVBV evolution. Furthermore, a sensitive loop-mediated isothermal amplification (LAMP) method was developed for rapid detection of SVBV isolates, which could be especially suitable for seedling propagation, virus-free culture and routine diagnostics in field investigation. This study offers new understanding of the molecular evolution and may help to improve the management of SVBV.

P1 of strawberry vein banding virus, a multilocalized protein, functions as a movement protein and interacts with the coat protein

Although the complete nucleotide sequence of strawberry vein banding virus (SVBV) has been determined and bioinformatic analysis has revealed that the SVBV genome could encode seven proteins, the precise function of each protein is unclear. This study provided evidence that the P1 protein of SVBV (SVBV-P1) possesses the following features. Bioinformatic and subcellular localization analyses showed that SVBV-P1 is localized in the cytoplasm and cell walls of epidermal cells in Nicotiana benthamiana, and it forms inclusion bodies associated with microtubules and the endoplasmic reticulum. Dilution experiments demonstrated that SVBV-P1 could move from the original agro-infiltrated cells to adjacent cells in N. benthamiana leaves. Further trans-complementation experiments demonstrated that SVBV-P1 could facilitate the intercellular movement of a movement-deficient potato virus X mutant in N. benthamiana leaves. Finally, yeast two-hybrid and bimolecular fluorescence complementation assays revealed that SVBV-P1 could interact with the SVBV coat protein, which is a major component of Caulimovirus virions. Results of the electrophoretic mobility shift assay indicated that SVBV-P1 lacks DNA-binding capability. In summary, the results suggest that SVBV-P1 is probably a movement protein of SVBV, providing new insights into the function of movement proteins of the Caulimovirus genus.

Strawberry vein banding virus (vein banding of strawberry)

Strawberry vein banding virus (vein banding of strawberry)

Effect of strawberry vein banding virus and strawberry mottle virus co-infection on the growth and development of strawberry

Strawberry mottle virus (SMoV) and strawberry vein banding virus (SVBV) cause diseases on strawberry plants, but the effect of coinfection of SMoV and SVBV on the growth, development, and defense system of strawberry (Fragaria × ananassa Duchesne) remains unknown. We investigated the effect of SMoV and SVBV co-infection on strawberry cultivar ‘Benihope’. The results showed that stem diameter, leaf size, leaf number, relative chlorophyll content, total chlorophyll content, photosynthetic parameters, and stomatal aperture of SMoV and SVBV co-infected strawberry (VIS) plants were in a weaker level than uninfected control plants, indicating that viruses inhibited the growth and photosynthesis of strawberry plants. Furthermore, the initiation of flowering and fruiting stages of VIS plants were delayed by about three weeks compared with the controls, and the fruiting period was shortened, demonstrating that the reproduction of VIS plants was inhibited. Fruit quality was damaged in VIS plants due to a significant increase in fruit firmness and titratable acidity and decrease in total soluble solid content than control fruits. More dead cells and H2O2 accumulated along the veins of VIS leaves, and the content of abscisic acid and catalase activity significantly increased, whereas anthocyanin content was lower than that of control plants. The results demonstrate that SVBV and SMoV coinfection inhibits the growth and development of ‘Benihope’ strawberry plants, and the plants respond to viruses by regulating stomatal aperture, the accumulation of ABA and antioxidants. To our knowledge, this study contributes information to understand how both viruses impair the strawberry growth and development for the first time.

FvZFP1 confers transgenic Nicotiana benthamiana resistance against plant pathogens and improves tolerance to abiotic stresses

Zinc finger proteins can induce plant resistance and activate the expression of molecules involved in the resistance pathway in response to harsh environmental conditions. Previously, we found that a novel Fragaria vesca zinc finger protein interacts with the P6 protein encoded by a strawberry vein banding virus. However, the molecular mechanism of the zinc finger protein in plant stress resistance is still unknown. In this study, we reported the identification and functional characterization of the RING finger and CHY zinc finger domain-containing protein 1 (FvZFP1). The overexpression of FvZFP1 in Nicotiana benthamiana enhanced resistance to tobacco mosaic virus (TMV) and Pseudomonas syringae pv. tomato DC3000 (Pst DC3000) infection by increasing ROS content. Additionally, FvZFP1 overexpression upregulated salicylic acid (SA) response-related gene expression as well as SA accumulation following TMV and Pst DC3000 infection. Furthermore, FvZFP1 overexpression resulted in increased salinity and drought stress tolerance by increasing SOD activity and decreasing MDA content. Overexpression of FvZFP1 also activated the ABA pathway under salinity or drought conditions. To our knowledge, this is the first study on the involvement of F. vesca zinc finger protein in crosstalk between biotic and abiotic stress signaling pathways, suggesting that FvZFP1 is a candidate gene for the improvement of resistance in response to multiple stresses.

High Incidence of Strawberry Polerovirus 1 in the Czech Republic and Its Vectors, Genetic Variability and Recombination.

In total, 332 strawberry plants from 33 different locations in the Czech Republic with or without disease symptoms were screened by RT-PCR for the presence of strawberry polerovirus 1 (SPV1) and five other viruses: strawberry mottle virus, strawberry crinkle virus, strawberry mild yellow edge virus, strawberry vein banding virus, and strawberry virus 1. SPV1 was detected in 115 tested strawberry plants (35%), including 89 mixed infections. No correlation between symptoms and the detected viruses was found. To identify potential invertebrate SPV1 vectors, strawberry-associated invertebrate species were screened by RT-PCR, and the virus was found in the aphids Aphis forbesi, A. gossypii, A. ruborum, A. sanquisorbae, Aulacorthum solani, Chaetosiphon fragaefolii, Myzus ascalonicus, and several other non-aphid invertebrate species. SPV1 was also detected in aphid honeydew. Subsequent tests of C. fragaefolii and A. gossypii virus transmission ability showed that at least 4 h of acquisition time were needed to acquire the virus. However, 1 day was sufficient for inoculation using C. fragaefolii. In conclusion, being aphid-transmitted like other tested viruses SPV1 was nevertheless the most frequently detected agent. Czech SPV1 isolates belonged to at least two phylogenetic clusters. The sequence analysis also indicated that recombination events influence evolution of SPV1 genomes.

Detection of Strawberry vein banding virus (SVBV) and Identification of Viruliferous Insects Associated with Strawberry Plants (Fragaria sp.) in Bali

Plant pests and diseases cause decreases in strawberry yield in Bali, including plant viruses. Strawberry vein banding virus (SVBV) is a virus that infects strawberry plants and is transmitted by insects. However, studies about this disease in Bali are still limited. This study aimed to detect SVBV within insect bodies and determine the insect species of its vector. Methods used included (1) sampling; (2) detection of SVBV from insect bodies using primers (SVBV F/SVBV R) and PCR; and (3) molecular identification of viruliferous insect with primers (LCO 1490 F/HCO 2198 R) using PCR and sequencing analysis. This study successfully detected SVBV DNA in an insect from three insect families associated with strawberry plants in Pancasari Village, Buleleng Regency, Bali. Results from the nucleotide sequences analysis in SVBV viruliferous insects indicate that the insect was Myzus persicae.

The occurrence of strawberry virus 1 infecting strawberry in Shandong province, China.

Strawberry (Fragaria × ananassa Duch.) is one of the most important horticultural plants worldwide with high economic and nutritional value. Strawberry associated virus 1 (SaV1) is a putative Cytorhabdovirus isolated from strawberry in Fujian province, China (Ding et al., 2019). Strawberry virus 1 (StrV-1) is another putative Cytorhabdovirus characterized from F. ananassa and F. vesca in Czech Republic (Fránová et al., 2019). The complete genomes of isolates of SaV1 and StrV-1 share 79 to 98% nucleotide (nt) identities. In August 2020, foliar chlorotic spots or streaks were observed in four strawberry cultivars (cv. Honeoye, Mibao, 8128 and All Star) in Yantai, Shandong province, China. To identify the associated viruses, symptomatic leaves from two plants of each cultivar (8 samples) were pooled for high-throughput sequencing (HTS). Total RNA was extracted from the composite sample and used for constructing a cDNA library after ribosomal RNA (rRNA)-depletion. Sequencing was carried out on Illumina Hiseq 4000 (Novogene, China). Raw reads were filtered, trimmed and de novo assembled as described previously (Grabherr et al., 2013; Zhou et al. 2020). The resulting contigs were screened by BLASTn and BLASTx against GenBank database. Subsequent analyses indicated the presence of strawberry vein banding virus, strawberry pallidosis associated virus and strawberry mottle virus in the analyzed sample, which had been reported previously in strawberry (Martin and Tzanetakis, 2013; Shi et al., 2018; Bhagwat et al., 2016). Besides, five contigs ranging from 266 to 6,057 nt were obtained. They shared 87 to 91% nt sequence identity with StrV-1 isolate B (GenBank accession no. MK211271). To confirm StrV-1 infection in the strawberry plants, total RNA was isolated from all eight samples using RNAprep Pure Plant Plus Kit (Tiangen, China). Reverse transcription polymerase chain reaction (RT-PCR) was conducted with two pairs of specific primers StrVp1 (Forward: 5'-CATTACTGAAGCATTCCGTG-3'/Reverse: 5'-AGATATCACGCACAGTGAC-3'), and StrVp2 (Forward: 5'-TTGCGCGAAGCGGATGTCCG-3'/Reverse: 5'-GGCTGCCAGAGCGTTGGATG-3'), targeting nt positions 70-1,231 and 7,825-9,348 of StrV-1 isolate B, respectively. Fragments with the expected sizes were amplified from two samples of cv. All Star. The amplicons were cloned, sequenced, and deposited in GenBank under accession no. MW419123-124 and MW645247-248. Both protein encoding sequences shared 91 to 92% and 80 to 84% nt identities with the corresponding sequences of StrV-1 isolate B and SaV1, respectively, indicating that the isolates from this study are genetic variants of StrV-1 and distantly related to SaV1. Crude sap was prepared by homogenizing leaf tissues of StrV-1 infected strawberry in 0.02 mol/L sodium phosphate buffer with 0.45% (w/v) sodium diethyldithiocarbamate thihydrate, then gently rubbed onto five healthy Nicotiana benthamiana plants. Neither the inoculated leaves nor the systemically infected leaves showed obvious symptoms seven days post inoculation. However, StrV-1 was detected by RT-PCR in all five N. benthamiana plants as described above. In addition, a survey of strawberry greenhouses was conducted in August 2020 and approximately 10% of plants in a 667 m2 greenhouse in Yantai had StrV-1-like symptoms. To the best of our knowledge, this is the first report of the occurrence of StrV-1 infecting strawberry in Shandong province, China. Our findings expand the geographic range and genetic diversity of StrV-1 and indicate it could be a potential virus threat to strawberry production in China.

Complete genome sequence of a putative new and distinct caulimovirus from Metaplexis japonica (Thunb.) Makino in China

In 2019, a new disease characterized by yellow mottling on leaves was observed on Metaplexis japonica (Thunb.) Makino plants in Liaoning, China. Using RNA sequencing and PCR with overlapping primers, the complete nucleotide sequence of the circular double-stranded DNA genome of a new virus similar to caulimoviruses in diseased samples was determined. The genome comprised 7733 base pairs and was predicted to encode six proteins. It had the closest relationship to a caulimovirus, strawberry vein banding virus, based on sequence comparisons and phylogenetic analysis. Species-level sequence divergences from caulimoviruses were also observed in the conserved genomic regions. A complete episomal viral genome sequence in symptomatic M. japonica plants was identified, and the name "metaplexis yellow mottle-associated virus" is proposed for this virus.

Sequencing a Strawberry Germplasm Collection Reveals New Viral Genetic Diversity and the Basis for New RT-qPCR Assays.

Viruses are considered of major importance in strawberry (Fragaria × ananassa Duchesne) production given their negative impact on plant vigor and growth. Strawberry accessions from the National Clonal Germplasm Repository were screened for viruses using high throughput sequencing (HTS). Analyses of sequence information from 45 plants identified multiple variants of 14 known viruses, comprising strawberry mottle virus (SMoV), beet pseudo yellows virus (BPYV), strawberry pallidosis-associated virus (SPaV), tomato ringspot virus (ToRSV), strawberry mild yellow edge virus (SMYEV), strawberry vein banding virus (SVBV), strawberry crinkle virus (SCV), strawberry polerovirus 1 (SPV-1), apple mosaic virus (ApMV), strawberry chlorotic fleck virus (SCFaV), strawberry crinivirus 4 (SCrV-4), strawberry crinivirus 3 (SCrV-3), Fragaria chiloensis latent virus (FClLV) and Fragaria chiloensis cryptic virus (FCCV). Genetic diversity of sequenced virus isolates was investigated via sequence homology analysis, and partial-genome sequences were deposited into GenBank. To confirm the HTS results and expand the detection of strawberry viruses, new reverse transcription quantitative PCR (RT-qPCR) assays were designed for the above-listed viruses. Further in silico and in vitro validation of the new diagnostic assays indicated high efficiency and reliability. Thus, the occurrence of different viruses, including divergent variants, among the strawberries was verified. This is the first viral metagenomic survey in strawberry, additionally, this study describes the design and validation of multiple RT-qPCR assays for strawberry viruses, which represent important detection tools for clean plant programs.

Synthetic Promoters from Strawberry Vein Banding Virus (SVBV) and Dahlia Mosaic Virus (DaMV).

We have constructed two intra-molecularly shuffled promoters, namely S100 and D100. The S100 recombinant promoter (621bp) was generated by ligation of 250bp long upstream activation sequence (UAS) of Strawberry vein banding virus (SV10UAS; - 352 to - 102 relative to TSS) with its 371bp long TATA containing core promoter domain (SV10CP; - 352 to + 19). Likewise, 726bp long D100 promoter was constructed by fusion of 170bp long UAS of Dahlia mosaic virus (DaMV14UAS; - 203 to - 33) with its 556bp long core promoter domain (DaMV4CP; - 474 to + 82). S100 and D100 promoters showed 1.8 and 2.2 times stronger activities than that of the CaMV35S promoter. The activity of the promoters is comparable to that of the CaMV35S2 promoter. Transcript analysis employing qRT-PCR and histochemical assays supported the above findings. Abscisic acid and salicylic acid induce the activity of the D100 promoter. Leaf protein obtained from Nicotiana tabacum plant expressing NSD2 gene (Nigella sativa L. defensin 2) driven by the D100 promoter showed antifungal activity against Alternaria alternata and Phoma exigua var. exigua and antibacterial activity against Pseudomonas aeruginosa and Staphylococcus aureus. Strong S100 and D100 promoters have potential to become efficient candidates for plant metabolic engineering and molecular pharming.

Complete genome sequence of two strawberry vein banding virus isolates from China

Complete genome sequence of two strawberry vein banding virus isolates from China

First report of the complete genomic sequences of strawberry mild yellow edge virus and strawberry vein banding virus isolated in Japan

Strawberry vein banding virus (SVBV) and strawberry mild yellow edge virus (SMYEV) have caused disease in strawberries for many years in Japan, but little is known about their molecular properties. We thus determined the complete genomic sequence of an isolate of each virus from Tochigi Prefecture. A nucleotide sequence analysis showed that SVBV is closely related to Chinese isolates, whereas SMYEV is closely related to German and Argentine isolates. This is the first report describing the complete genome sequences of SVBV and SMYEV isolated in Japan. Moreover, we constructed an infectious SMYEV clone, which induced mild yellowing on inoculated strawberry plants.

Incidence of Aphid-Transmitted Strawberry Viruses in Korea and Phylogenetic Analysis of Korean Isolates of Strawberry Mottle Virus

Among more than 30 viruses infecting strawberry, aphid-transmitted viruses including Strawberry mild yellow edge virus (SMYEV), Strawberry mottle virus (SMoV), Strawberry crinkle virus (SCV), and Strawberry vein banding virus (SVBV) have been considered as the most economically important viruses of strawberry in the world. To determine the incidence of these four viruses in major Korean strawberry cultivars, field surveys were conducted in major production areas during 2018-2019. In our surveys, SMYEV and SMoV were detected with low infection rates of 0.7% and 1.3%, respectively, whereas SCV and SVBV were not detected. No obvious symptoms were observed in the strawberry plants infected by SMYEV or SMoV. Since no sequences of SMoV Korean isolates have been reported, we initially determined nucleotide sequence of the 3' untranslated region (UTR) of seven SMoV isolates obtained during the surveys. The 3' UTR sequences (782 nt) of seven Korean isolates were phylogenetically compared with those of the previously reported SMoV isolates. Phylogenetic analysis revealed that most Korean isolates are closely related to Canadian isolates and only little evolutionary differentiation occurred among the Koreans isolates. This might be due to the low incidence of SMoV in strawberry in Korea.