To Turnip Mosaic Virus Research Articles

First Record of Turnip mosaic virus Infecting Watercress in Venezuela.

During 2001, watercress (Rorippa nasturtium-aquaticum) plants displayed in vegetable markets located in the district capital, Caracas, showed severe leaf distortion, chlorosis, and mosaic. Viral etiology was suspected, and several plants were brought to the lab for further analyses. Electron microscopic studies of leaf-dip preparations from symptomatic samples revealed flexuous viral particles 750 nm long. Infected cells contained pinwheel inclusions and scrolls typical of those associated with infection by a potyvirus. The virus was sap-transmitted back to watercress, which developed symptoms identical to those first observed. Disease symptoms were also reproduced on Nicotiana benthamiana using mechanical inoculation with watercress-infected sap. All samples were tested by enzyme-linked immunosorbent assay, using polyclonal antibodies (Agdia, Elkhart, IN) to Turnip mosaic virus (TuMV), the only potyvirus that has been found infecting watercress plants (1). TuMV was detected in 88% of 100 samples taken from 18 markets on a single day. Symptoms were noted in every market when visited once a month during a 6-month period. The high percentage of TuMV-infected watercress in the 18 local markets (all 10 to 11 km from watercress fields) makes further epidemiological studies desirable. To our knowledge, this is the first report of TuMV infection of watercress in Venezuela.

Different classes of resistance to turnip mosaic virus in Brassica rapa

Pathotype-specific and broad-spectrum resistance to turnip mosaic virus (TuMV) have been identified in the diploid A genome brassica species Brassica rapa. The pathotype-specific resistance is effective against pathotype 1 isolates of TuMV, which are the most common in Europe. It is almost identical in its specificity to that of a mapped resistance gene (TuRB01) present in the A genome of the amphidiploid species Brassica napus. A mutant of a pathotype 1 isolate of TuMV (UK 1M) that is able to overcome TuRB01 also overcame the B. rapa resistance. This, combined with the fact that a single-nucleotide mutation in the cylindrical inclusion gene of TuMV that has been shown to induce a change from avirulence to virulence against TuRB01, had an identical effect on the B. rapa resistance, suggest that the two resistances are conditioned by the same gene. A second source of resistance in B. rapa prevented systemic spread of all TuMV isolates tested. A third source of resistance that appears to provide immunity to, or severely restrict replication of most isolates of TuMV has been characterised. This resistance source also prevented systemic spread of all TuMV isolates tested. Prior to this study, no resistance to pathotype 4 or pathotype 12 isolates of TuMV had ever been identified. For each of these three resistance sources, plant lines that are not segregating for some of the resistance phenotypes and that are presumably homozygous for the genes controlling these phenotypes have been generated. Strategies for further characterising and deploying these resistances in different Brassica species are described.

Genetics of resistance to five strains of turnip mosaic virus in Chinese cabbage

Inheritance of resistance to turnip mosaic virus (TuMV) strains C1, C2, C3, C4, and C5 in Chinese cabbage (Brassica campestris subsp. pekinensis) was evaluated using monoclonal antibodies. Crosses were made between a resistant line, ‘0–2’, and four susceptible line. ‘Seoul’ (SE),‘SSD31’ (SS), ‘Cheongbang’ (CH), and ‘Yaki 1 ho’ (YA), to determine the inheritance of resistance of ‘0–2’ in different genetic backgrounds. Resistance to TuMV was controlled by a single dominant gene or double dominant genes depending on the strain and cross. The resistance genes of ‘0–2’ were modified by susceptible parents such that a single dominant gene was involved in the ‘SS×0–2’ combination, but double dominant genes in the ‘SE×0–2’ against TuMV-C3 or TuMV-C5. ELISA tests using inoculated and noninoculated leaves in the same plant suggested that the dominant resistance genes inhibit virus movement rather than virus multiplication.

Evaluation of Rutabaga Cultivars for Turnip Mosaic Virus Resistance and the Inheritance of Resistance

Abstract Rutabaga (Brassica napus L. Group Napobrassica) cultivars were screened for resistance to turnip mosaic virus (TuMV), and the inheritance of resistance was studied. Immunity and resistance were found in four of 49 rutabaga cultivars evaluated. The cultivar ‘Sensation’ was immune to the Ontario strain of TuMV. In crosses between susceptible ‘Laurentian’ and resistant Line 165 and susceptible triazine-resistant ‘Laurentian’ and Line 165, TuMV resistance was determined by a single dominant gene.

Relationships among bean common mosaic virus, blackeye cowpea mosaic virus, azuki bean mosaic virus, and soybean mosaic virus.

The host range, transmission, cross-protection, antigenic relationships, and coat proteins of four distinct potyviruses (bean common mosaic virus (BCMV), blackeye cowpea mosaic virus (BlCMV), azuki bean mosaic virus (AzMV), and soybean mosaic virus (SMV)) were compared. BCMV, BlCMV, AzMV and SMV were easily distinguished by the host range and seed transmission. Two BCMV isolates, two BlCMV isolates and AzMV were serologically identical according to examination by agar gel diffusion plates containing 0.5% lithium 3, 5-diiodosalicylate. Five SMV isolates from Japan were serologically identical and distantly related to a SMV isolate from Thailand. BCMV, BlCMV and AzMV were distantly related to SMV. None of these viruses were serologically related to turnip mosaic virus (TuMV). Positive cross-protection was found between BCMV and BlCMV, between BCMV and AzMV, and between BlCMV and AzMV. The molecular weights of the coat proteins of the virus isolates estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, were 32.8×103(K) for two BCMV isolates, two BlCMV isolates and AzMV, 30.1K for five SMV isolates from Japan, 31.5K for a SMV isolate from Thailand, and 34K for TuMV. The patterns of the peptides of two BCMV isolates, two BlCMV isolates and AzMV after cleavage with Staphylococcus V8 protease appeared nearly identical. Likewise, polypeptide patterns of five SMV isolates from Japan were also very similar. Good correlation was found among serological typing, molecular weights, and peptide mapping data of 12 virus isolate proteins. These findings suggest that SMV is a distinct virus, while BCMV, BlCMV and AzMV are virus strains, not distinct viruses.

Selection for immunity in swede (Brassica napus) to infection by turnip mosaic virus

SUMMARYFully heritable immunity to turnip mosaic virus (TuMV) was found in swede (Brassica napus) cvs Ruta Otofte and Bangholm. Attempts to ‘break’ this immunity were unsuccessful. The reactions of two immune lines of cv. Ruta Otofte to cauliflower mosaic virus, clubroot (Plasmodiophora brassicae) and powdery mildew (Erysiphe cruciferarum) were unchanged compared with the unselected parent line. A symptomless response to TuMV inoculation (possibly immunity) was also found in cv. Acme but not in the clubroot resistant cv. Marian. The percentage of plants which gave a symptomless response to TuMV inoculation differed greatly between cultivars and some seed stocks.

Chicory: A Valuable Source of Resistance to Turnip Mosaic for Endive and Escarole1

Abstract In greenhouse tests, domestic and foreign accessions of Cichorium endivia L. were susceptible to turnip mosaic virus (TuMV), the most common and often destructive virus occurring in late plantings of endive and escarole in the Northeast United States, whereas those of chicory (C. intybus L.) and C. pumilum Jacq. were resistant. Thus, chicory represents a valuable source of TuMV resistance for interspecific gene transfer to endive and escarole. Resistance was dominant in F1 plants of C. intybus × C. endivia.

Inheritance and Linkage of Turnip Mosaic Virus and Downy Mildew (Bremia lactucae) Reaction in Lactuca serriola1

Abstract Data for resistance in Lactuca serriola L. to turnip mosaic virus (TuMV) and downy mildew were obtained from 5 F2 progenies of crosses between TuMV-susceptible, mildew-resistant, and TuMV-resistant, mildew-susceptible parents. The F1 progeny were TuMV and mildew-resistant. Of 1,103 F2 plants assayed 823 were TuMV-resistant and 280 TuMV-susceptible. A total of 834 mildew-resistant plants were observed, and 269 mildew-susceptible. Resistance to TuMV and mildew are each controlled by a single dominant allele, designated Tu and Dm, respectively. The TuMV gene, Tu tu, is linked with the mildew gene, Dm dm. In the repulsion phase, the crossover value was 12.0% ± 2.9. F2 progenies of crosses between TuMV-susceptible, mildew-resistant L. serriola and TuMV-susceptible, mildew-resistant L. sativa cv. ‘Calmar’ or ‘Imperial 410’, and crosses among cv. ‘Calmar’, ‘Imperial 410’, and ‘E-4’, indicated they possessed the same dominant allele for mildew-resistance, and the same recessive allele for TuMV-susceptibility.

Linkage of Turnip Mosaic Virus Susceptibility and Downy Mildew, Bremia lactucae, Resistance in Lettuce1

Abstract Data for resistance in Lactuca sativa L. to turnip mosaic virus (TuMV) and downy mildew were obtained from 8 F2 progenies of crosses between TuMV-susceptible, mildew-resistant, and TuMV-resistant, mildew-susceptible parents. The F1 progeny were TuMV and mildew resistant. Of 3,682 F2 plants assayed 2,773 were TuMV resistant and 909 TuMV susceptible. A total of 2,788 mildew-resistant plants were observed, and 904 mildew susceptible. Resistance to TuMV and mildew are each controlled by a single dominant gene, designated herein as Tu and Dm. The TuMV-susceptible gene, tu, is linked with the mildew-resistant gene, Dm. In the repulsion phase, the cross-over value was 12.5% ± 1.6.