scholarly journals Performance of Transgenic Tomatoes Expressing Cucumber Mosaic Virus CP Gene under Epidemic Conditions

HortScience ◽  
1998 ◽  
Vol 33 (6) ◽  
pp. 1032-1035 ◽  
Author(s):  
John F. Murphy ◽  
Edward J. Sikora ◽  
Bernard Sammons ◽  
Wojciech K. Kaniewski

Three processing tomato (Lycopersicon esculentum Mill.) lines engineered to express the cucumber mosaic virus (CMV) capsid protein (CP) gene were evaluated in the summers of 1995 and 1996 under high levels of naturally occurring CMV disease pressure. One tomato line expressed the capsid protein gene from a subgroup II isolate of CMV (line 11527), whereas two lines (12261 and 12295) expressed the capsid protein genes from a CMV subgroup I and a subgroup II isolate. Evaluation of CMV incidence based on symptomatic plants revealed that only 9% and 8% of the plants in line 11527 were infected in 1995 and 1996, respectively, 5 weeks after being transplanted. None of the plants in line 12261 developed symptoms in 1995, whereas 26% were symptomatic in 1996. There were no symptomatic plants in line 12295 in either the 1995 or the 1996 trial. In contrast to the CMV transgenic lines, 96% and 95% of the susceptible control plants were symptomatic by the 5-week rating period. CMV incidence in the CMV transgenic lines was much higher when infection was based on detection of virus by enzyme-linked immunosorbent assay (ELISA). This was particularly true in the 1996 trial where no less than 97% of the plants within a treatment were determined to be infected. Though a relatively high percentage of the transgenic plants were infected, the amount of CMV that accumulated in these plants was significantly less than in the susceptible controls, which may explain the occurrence of the attenuated symptoms. Despite CMV infection of the transgenic lines in the Alabama field trials, the performance of these lines could be of practical value to growers.

Plant Disease ◽  
2006 ◽  
Vol 90 (11) ◽  
pp. 1457-1457 ◽  
Author(s):  
N. Sudhakar ◽  
D. Nagendra-Prasad ◽  
N. Mohan ◽  
K. Murugesan

During a survey in January 2006 near Salem in Tamil Nadu (south India), Cucumber mosaic virus was observed infecting tomatoes with an incidence of more than 70%. Plants exhibiting severe mosaic, leaf puckering, and stunted growth were collected, and the virus was identified using diagnostic hosts, evaluation of physical properties of the virus, compound enzyme-linked immunosorbent assay (ELISA) (ELISA Lab, Washington State University, Prosser), reverse-transcription polymerase chain reaction (RT-PCR), and restriction fragment length polymorphism analysis (DSMZ, S. Winter, Germany). To determine the specific CMV subgroup, total RNA was extracted from 50 infected leaf samples using the RNeasy plant RNA isolation kit (Qiagen, Hilden, Germany) and tested for the presence of the complete CMV coat protein gene using specific primers as described by Rizos et al. (1). A fragment of the coat protein was amplified and subsequently digested with MspI to reveal a pattern of two fragments (336 and 538 bp), indicating CMV subgroup II. No evidence of mixed infection with CMV subgroup I was obtained when CMV isolates representing subgroups I (PV-0419) and II (PV-0420), available at the DSMZ Plant Virus Collection, were used as controls. Only CMV subgroup I has been found to predominantly infect tomato in the Indian subcontinent, although Verma et al. (2) identified CMV subgroup II infecting Pelargonium spp., an ornamental plant. To our knowledge, this is the first report of CMV subgroup II infecting tomato crops in India. References: (1) H. Rizos et al. J. Gen. Virol. 73:2099, 1992. (2) N. Verma et al. J. Biol. Sci. 31:47, 2006.


1998 ◽  
Vol 38 (4) ◽  
pp. 375 ◽  
Author(s):  
Z. Singh ◽  
M. G. K. Jones ◽  
R. A. C. Jones

Summary. Transgenic tobacco (Nicotiana tabacum) plants of (i) cv. Samsun NN containing the cauliflower mosaic virus 35S constitutive promoter linked to a defective replicase (DR) gene derived from cucumber mosaic virus (CMV) subgroup I isolate Fny, and (ii) cv. Xanthi containing the CaMV 35S promoter linked to the coat protein (CP) gene of CMV subgroup I isolate C were tested for resistance to various Australian isolates of CMV. The tobacco plants were challenged with 3 CMV subgroup 1 isolates (BNRR, BMR and B6) using sap inoculation. When used to challenge non-transgenic tobacco plants with 5 subgroup II CMV isolates from lupins (LY, LCH, LAcc, LGu and LD), this inoculation method did not result in systemic infection so graft inoculation was used instead to challenge transgenic plants with these 5 isolates. When plants of the line with the DR gene were challenged with the 3 subgroup I isolates, extreme resistance was revealed as none showed symptoms and CMV was not detectable by ELISA. When the same 3 isolates were inoculated to the 3 lines with the CP gene, resistance was characterised by fewer plants becoming virus infected, delayed systemic movement and, in the plants that were infected, partial remission of symptoms plus somewhat decreased virus concentration. Challenge of transgenic plants with DR or CP with the 5 subgroup II isolates resulted in fewer plants becoming infected. Actual numbers of plants infected varied with line and subgroup II isolate and the DR gene was as effective as the CP gene at decreasing infection. With subgroup II isolate LY, infection was associated with remission of symptoms and with the other 4 isolates with delayed systemic movement. Thus the DR gene approach was more effective than the CP approach in obtaining extreme resistance against Australian subgroup I isolates of CMV. These results suggest that introducing a similar DR gene construct made from a subgroup II isolate from lupins into commercial lupin cultivars may be a suitable strategy for obtaining extreme resistance to subgroup II isolates from lupins.


Plant Disease ◽  
1998 ◽  
Vol 82 (4) ◽  
pp. 391-396 ◽  
Author(s):  
John R. Stommel ◽  
Marie E. Tousignant ◽  
Thanda Wai ◽  
Rita Pasini ◽  
Jacobus M. Kaper

Field trials of transgenic tomato plants expressing an ameliorative satellite RNA of cucumber mosaic virus (CMV) were conducted to test the efficacy of satellite-transgenic technology to protect against CMV infection. Three transgenic tomato lines derived from two susceptible genotypes were evaluated over two growing seasons for viral symptoms and titers, satellite RNA expression, and fruit yield. Satellite-transgenic lines exhibited mild or no CMV symptoms and low viral titers relative to nontransformed plants. A significant negative correlation between satellite RNA levels and disease severity was evident in transgenic lines. Total marketable yield of CMV-infected satellite-transgenic lines was 40 to 84% greater than that of CMV-infected parent lines. Importantly, yield of CMV-infected satellite-transgenic lines did not differ significantly from mock-inoculated parent lines. Risk assessment results demonstrated low levels of satellite RNA transmission within the test site and no evidence of satellite RNA-induced damage on surrounding plants.


Plant Disease ◽  
1998 ◽  
Vol 82 (8) ◽  
pp. 960-960
Author(s):  
V. A. Mavrodieva ◽  
D. J. Barbara ◽  
N. J. Spence

Cucumber mosaic virus (CMV) is one of the most important viruses in Bulgaria, causing severe losses to agriculture, but little is known about the occurrence and distribution of subgroups within the country or the presence of satellite RNAs (satRNAs). Samples showing typical symptoms (mild to severe mosaic, vein clearing, vein necrosis, leaf deformation, stunting, and fruit necrosis) on several important crops (tomato, cucumber, pepper, bean, courgette, and tobacco) were collected from the main agricultural regions of the country. Isolates were maintained by sap inoculation in tobacco plants. Total RNAs were isolated from 38 samples (including two from bean) and used in reverse transcription-polymerase chain reaction (RT-PCR) assay with primers corresponding to the coat protein (CP) gene of RNA3 (3). A single strong band, 870 bp in length, was produced from all these samples. Amplified products were analyzed for subgroup differentiation by digestion with the restriction endonucleases MspI (3), PvuII, and EcoRI. The MspI subgroups 2 and 1 designated by Rizos et al. (3) according to their restriction endonuclease digest data correspond to the subgroups I and II widely used in the literature and based on serology, sequence data, and other properties. In this report, the subgroups are referred to as I and II for the sake of clarity. Isolates in both subgroups were found in all the main regions of Bulgaria. A few variations in MspI and EcoRI digestion patterns were seen, indicating some variability between isolates within subgroups. Only five samples, three from tomato and two from pepper, were found to be subgroup II. Subgroup I isolates were found in all the crops sampled. The PCR product from one representative isolate of each subgroup was cloned and sequenced by standard procedures. Alignment of the nucleotide and predicted amino acid sequences with published sequences of the CMV CP gene confirmed that the amplified products were derived from CMV. A further eight samples from bean gave only weak amplification and digestion of the products suggested they were likely to be subgroup II. However, these samples were unusual in not inducing symptoms in inoculated tobacco and in being difficult to propagate. The nature of these virus isolates is therefore unclear. Only a single occurrence in Bulgaria of satRNA of CMV has been reported (4) but in this study satRNAs were detected by RT-PCR (1) in total plant RNA extracts of 21 of the 38 samples tested. Amplified products of two of them, NB and 146D, were sequenced; comparison with published sequences confirmed that they were derived from CMV satellite. As expected from the symptoms induced by these isolates, a sequence homologous to the domain of satRNA Y responsible for bright yellow mosaic on tobacco (2) was identified in satRNA NB but not in satRNA 146D. satRNAs were not detected in the eight bean samples that had given only weak amplification with the CMV CP gene primers. The results presented here clearly demonstrate the presence of both subgroups of CMV in Bulgaria. Although CMV in Bulgaria has been studied previously by serological methods, no evidence had been found for the presence of subgroup II. References: (1) F. Grieco et al. Virology 229:166, 1997. (2) C. Masuta and Y. Takanami. Plant Cell 1:1165, 1989. (3) H. Rizos et al. J. Gen. Virol. 73:2099, 1992. (4) E. Stoimenova. J. Cult. Collect. 1:45, 1995.


2006 ◽  
Vol 96 (11) ◽  
pp. 1237-1242 ◽  
Author(s):  
H. Xu ◽  
J. Nie

Alfalfa mosaic virus (AMV) was detected in potato fields in several provinces in Canada and characterized by bioassay, enzyme-linked immunosorbent assay, and reverse-transcription polymerase chain reaction (RT-PCR). The identity of eight Canadian potato AMV isolates was confirmed by sequence analysis of their coat protein (CP) gene. Sequence and phylogenetic analysis indicated that these eight AMV potato isolates fell into one strain group, whereas a slight difference between Ca175 and the other Canadian AMV isolates was revealed. The Canadian AMV isolates, except Ca175, clustered together among other strains based on alignment of the CP gene sequence. To detect the virus, a pair of primers, AMV-F and AMV-R, specific to the AMV CP gene, was designed based on the nucleotide sequence alignment of known AMV strains. Evaluations showed that RT-PCR using this primer set was specific and sensitive for detecting AMV in potato leaf and tuber samples. AMV RNAs were easily detected in composite samples of 400 to 800 potato leaves or 200 to 400 tubers. Restriction analysis of PCR amplicons with SacI was a simple method for the confirmation of PCR tests. Thus, RT-PCR followed by restriction fragment length polymorphism analysis may be a useful approach for screening potato samples on a large scale for the presence of AMV.


Plant Disease ◽  
2001 ◽  
Vol 85 (4) ◽  
pp. 447-447 ◽  
Author(s):  
X. D. Li ◽  
Y. Q. Li ◽  
H. G. Wang

Flue-cured tobacco is an important crop in Henan Province, China. During the 2000 growing season, many tobacco plants showed various degrees of mottling, mosaic, vein clearing, or vein necrosis in most of the counties. Some plants even died at an early stage of growth. A survey was conducted in May-June in several tobacco-growing counties, and the incidence of symptomatic plants in individual fields ranged from 10 to 85%. The most widely planted tobacco varieties, NC89, K326, and K346, were highly susceptible. Symptomatic plants were collected from Jiaxian and Xiangcheng counties and samples were tested by enzyme-linked immunosorbent assay for Tobacco mosaic virus (TMV), Cucumber mosaic virus (CMV), Potato virus Y (PVY), and Potato virus X (PVX). Of 65 samples tested, 21 were positive for only PVY, 16 positive for only CMV, one each was positive for only TMV or PVX. Nineteen samples were doubly infected with various combinations of these viruses and six were infected with combinations of three viruses. The causal agent(s) in the remaining sample could not be determined. In total, CMV was detected in 40 samples, PVY in 38, PVX in 10, and TMV in 7 samples. TMV and CMV used to be the most important viruses and PVY occurred only rarely. But PVY has become prevalent in Henan and in neighboring Shandong province (2). CMV and TMV were reported to be the most prevalent viruses in Shanxi (1) and Fujian Provinces (3). Because resistant varieties are not available, and mixed infections are more common, the results presented here explain why huge damage is occurring in tobacco crops in recent years. Some varieties are partially resistant to TMV and CMV but the varieties commonly grown are highly susceptible to PVY. Therefore, breeding for resistance to viruses, especially to PVY, is urgent to control the occurrence of tobacco viral diseases. References: (1) J. L. Cheng et al. Acta Tabacaria Sin. 4:43, 1998. (2) J. B. Wang et al. Chinese Tobacco Sci. 1:26, 1998. (3) L. H. Xie et al. Acta Tabacaria Sin. 2:25, 1994.


Plant Disease ◽  
2005 ◽  
Vol 89 (5) ◽  
pp. 529-529 ◽  
Author(s):  
Y. K. Chen ◽  
C. C. Yang ◽  
H. T. Hsu

Allamanda (Allamanda cathartica L., family Apocynaceae) is native to Brazil and is a popular perennial shrub or vine ornamental in Taiwan. Plants showing severe mosaic, rugosity, and leaf distortion symptoms on leaves are common in commercial nurseries and private gardens. Examination of crude sap prepared from symptomatic leaves using an electron microscope revealed the presence of spherical virus particles with a diameter of approximately 28 nm. The virus was mechanically transmitted to indicator plants and induced symptoms similar to those incited by Cucumber mosaic virus (CMV). The virus caused local lesions on inoculated leaves of Chenopodium quinoa and C. amaranticolor and systemic mosaic in Cucumis sativus, Lycopersicon esculentum, Nicotiana benthamiana, N. glutinosa, N. rustica, and N. tabacum. On N. tabacum, necrotic ringspots developed on inoculated leaves followed by systemic mosaic. Tests of leaf sap extracted from naturally infected allamanda and inoculated indicator plants using enzyme-linked immunosorbent assay were positive to rabbit antiserum prepared to CMV. Viral coat protein on transblots of sodium dodecyl sulfate-polyacrylamide gel electrophoresis reacted with CMV subgroup I specific monoclonal antibodies (2). With primers specific to the 3′-half of RNA 3 (1), amplicons of an expected size (1,115 bp) were obtained in reverse transcription-polymerase chain reaction (RT-PCR) using total RNA extracted from infected allamanda and N. benthamiana. The amplified fragment (EMBL Accession No. AJ871492) was cloned and sequenced. It encompasses the 3′ part of the intergenic region of RNA 3 (158 nt), CP ORF (657 nt), and 3′ NTR (300 nt) showing 91.8–98.9% and 71.4–72.8% identities to those of CMV in subgroups I and II, respectively. Results of MspI-digested restriction fragment length polymorphism patterns of the RT-PCR fragment and the nucleotide sequence analysis indicate that the CMV isolate from allamanda belongs to subgroup IB, which is predominant on the island. To our knowledge, CMV is the only reported virus that infects allamanda and was first detected in Brazil (3), and this is the first report of CMV infection in allamanda plants occurring in Taiwan. References: (1) Y. K. Chen et al. Arch. Virol. 146:1631, 2001. (2) H. T. Hsu et al. Phytopathology 90:615, 2000. (3) E. W. Kitajima. Acta. Hortic. 234:451, 1988.


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