The occurrence in north-east Spain of a variant of tomato spotted wilt virus (TSWV) that breaks resistance in tomato ( Lycopersicon esculentum ) containing the Sw-5 gene Plant Pathol. 52 407 Aramburu, J. Rodriguez, M. 1999 Evaluation of commercial
David G. Riley, Shimat V. Joseph, W. Terry Kelley, Steve Olson, and John Scott
Matthew D. Robbins, Mohammed A.T. Masud, Dilip R. Panthee, Randolph G. Gardner, David M. Francis, and Mikel R. Stevens
. Tomato spotted wilt virus (TSWV) and Phytophthora infestans (Mont.) de Bary (late blight) are responsible for substantial tomato crop losses worldwide ( Foolad et al., 2008 ; Fry and Goodwin, 1997 ; Kim and Mutschler, 2005 , 2006 ; Mumford et al
Jong Wook Kim, Thomas L. German, and Samuel S. M. Sun
Nucleocapsid protein (N) gene was isolated from tomato spotted wilt virus (TSWV) Hawaiian L isolate, and introduced into Nicotiana tabacum cv. Xanthi nc in order to test for “CP-mediated protection”. Agrobacterium tumefaciens-mediated transformation was performed. The integrity and the expression of N gene were verified by Southern blot and Northern blot analysis, and the N protein in the transgenic tobacco plants were determined by ELISA and Western blot analysis. Several first generation of transgenic tobacco were tested for virus resistance. Comparably smaller numbers of the local lesions were developed with several day of delay in the in-frame transformants.
Olga Fedorowicz, Grzegorz Bartoszewski, Maria Kamińska, Pravda Stoeva, and Katarzyna Niemirowicz-Szczytt
This study was undertaken to remedy significant yield losses in commercial tomato (Lycopersicon esculentum Mill.) and tobacco (Nicotiana tabacum L.) production caused by tomato spotted wilt virus (TSWV). One of the possible sources of resistance can be incorporation into the host plant of a viral nucleoprotein (N) gene by Agrobacterium-mediated transformation. Twelve primary transformants of tomato and 141 of tobacco were analyzed for the expression of the N gene and for resistance to the TSWV infection. The tests have demonstrated that transgenic plants were protected against virus infection irrespective of whether or not they contained detectable levels of the translational product.
S.J. Scott, M. Stevens, and R.C. Gergerich
Seedlings of eight accessions of L. hirsutum and susceptible L. esculentum `VF Pink' controls were spray inoculated twice in the greenhouse with tomato spotted wilt virus (TSWV) Arkansas 85-9. Plants lacking symptoms were reinoculated, then evaluated for TSWV by enzyme-linked immunosorbent assay (ELISA). Controls were consistently infected; sixty noninfected L. hirsutum were propagated by cuttings and inoculated with TSWV isolates T2 (lettuce), G-87 (gloxinia), 87-34 (tomato) and a mixture of the four isolates. All selections became infected in at least one test, but systemic infection was often delayed. Additional wild Lycopersicon species and numbers of accessions evaluated for resistance to TSWV include L. cheesmanii (9), L. chmielewskii (17), L. hirsutum (24), L. hirsutum f. glabratum (17), L. parviflorum (4) and L. pennellii (44). No new sources of strong resistance have been identified yet. Evaluation of additional species and accessions is continuing.
M.J. Díez, S. Roselló, F. Nuez, J. Costa, M.S. Catalá, and A. Lacasa
Seedlings of three tomato (Lycopersicon esculentum Mill.) cultivars [`RDD', carrier of the Sw5 gene, which confers resistance to tomato spotted wilt virus (TSWV); `Pitihué', tolerant to the virus; and the susceptible cultivar Rutgers] were placed at the four- to five-leaf stage in cages containing a population of viruliferous thrips (Frankliniella occidentalis Perg.), and remained there for 0, 7, or 15 days. Plants were subsequently transplanted either into the open field or in tunnels protected with a mesh of 14 × 10 threads/cm. Systemic symptoms and number of dead plants were recorded and enzymelinked immunosorbent assays (ELISA) were performed. `Rutgers' exhibited severe systemic symptoms regardless of treatment and a high number of plants died. The level of infected plants remained low when protective measures were applied to seedlings of `Pitihué' and acceptable yields were obtained. In open air cultivation, where seedling infection was severe, <20% of `RDD' plants became infected and high yields were obtained; protected cultivation did not reduce yield. Although the percentage of infected plants was higher when cultivated under mesh, the yield of all three cultivars was greater than in the open field. The environment created under mesh stimulated growth, neutralizing the effect of the infection.
S.J. Scott, M. Stevens, and R.C. Gergerich
Three methods to inoculate Lycopersicon esculentum 'VF Pink' seedlings with tomato spotted wilt virus (TSWV) were compared. Treatments were 1) two inoculations by hand (rubbing leaves with a sterile cotton swab), 2) a single inoculation using a paint sprayer at 3.56 × 105 N· m-2, and 3) two spray inoculations. All three methods were effective (>95% infection) under moderate temperatures in the spring, but hand inoculation was not effective under hot conditions in the summer. In another experiment, spray inoculation was used to compare effects of light intensity and the leaf inoculated on susceptibility of L.. hirsutum PI 127826, L. pimpinellifoliom LA 1580 and `VF Pink' to TSWV isolate 85-9. All three genotypes were susceptible under full sun and 60% shade cloth in the greenhouse. Inoculation of youngest leaves produced the highest virus titer. Background optical density for noninoculated plants differed between lower and upper leaves in the ELISA assay.
Juan C. Diaz-Perez, D. Bertrand, and D. Giddings
Tomato spotted wilt virus (TSWV) can cause serious damage to tomato, pepper, lettuce, and other crops. The virus is transmitted by several species of thrips. The objective of this study was to determine the effect of the time (t, days after transplanting) when TSWV symptoms first appeared on tomato plant size and fruit yield. Tomato (`Florida-47') plants were drip-irrigated and planted over black plastic mulch. The experiment was carried out in Tifton, Ga., during Spring 1999. High populations of thrips were detected since early stages of plant development, which resulted in a high incidence of TSWV. Plant fresh weight was significantly higher (r 2 = 0.632, n = 216) the later in plant development TSWV symptoms first appeared (i.e., with increasing t values). Total fruit production of individual plant linearly increased with increasing t values (r 2 = 0.664, n = 216). As with total fruit production, fruit marketable yield was also higher with increasing t values; however, marketable yield was significantly reduced even when plants were infected later in the season (t > 55 days after transplanting). Our results suggest that it is important to keep tomato plants free from TSWV as long as possible. This applies to both developing and developed plants.
Santiago García-Martínez, Adrián Grau, Aranzazu Alonso, Fernando Rubio, Pedro Carbonell, and Juan J. Ruiz
virus and Tomato spotted wilt virus HortScience 49 1465 1466 Lewis, R.S. Linger, L.R. Wolff, M.F. Wernsman, E.A. 2007 The negative influence of N -mediated TMV resistance on yield in tobacco: Linkage drag versus pleiotropy Theor. Appl. Genet. 115 169
Randy G. Gardner and Dilip R. Panthee
NC 58S, NC 123S, NC 127S, and NC 132S are fresh-market tomato ( Solanum lycopersicum L.) breeding lines that have the single dominant gene Sw-5 for resistance to tomato spotted wilt virus (TSWV) along with other important disease resistance genes