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.
Olga Fedorowicz, Grzegorz Bartoszewski, Maria Kamińska, Pravda Stoeva, and Katarzyna Niemirowicz-Szczytt
Jean-Michel Hily, Ralph Scorza*, and Michel Ravelonandro
We have shown that high-level resistance to plum pox virus (PPV) in transgenic plum clone C5 is based on post-transcriptional gene silencing (PTGS), otherwise termed RNA silencing (Scorza et al. Transgenic Res. 10:201-209, 2001). In order to more fully characterize RNA silencing in woody perennial crops, we investigated the production of short interfering RNA (siRNA) in transgenic plum clones C3 and C5, both of which harbor the capsid protein (CP) gene of PPV. We used as a control, plum PT-23, a clone only transformed with the two marker genes, NPTII and GUS. We show in the current report that C5 constitutively produces two classes of siRNA, the short (21-22 nucleotides) and long (≈27 nucleotides) species in the absence of PPV inoculation. Transgenic susceptible clone C3 and the control clone PT-23, when healthy, produce no siRNA. Upon infection, these clones produce only the short siRNA (21-22 nt). This siRNA production suggests that plum trees naturally respond to virus infection by initiating PTGS or PTGS-like mechanisms. This study also suggests that high-level virus resistance in woody perennials may require the production of both the short and long size classes of siRNA, as are produced by the resistant C5 plum clone.
Kullanart Obsuwan, Wayne B. Borth, John Hu, and Adelheid R. Kuehnle
A Cymbidium mosaic virus movement protein gene with a site-specific mutation (mut11) under control of a ubiquitin promoter was inserted using biolistics into two Dendrobium varieties with the intention of creating CymMV-resistant orchids. Presence of the transgene in regenerated plants of D. × Jaquelyn Thomas `Uniwai Mist' and D. x Jaq–Hawaii `Uniwai Pearl' was confirmed by PCR using genomic DNA, and mut11-positive plants were potted ex vitro. Forty-two transgenic plants and four non-transgenic control plants at the 4- to 6-leaf stage were inoculated with a 1:1000 dilution of CymMV obtained from infected orchids. Plants were analyzed for systemic infection using tissue blot immunoassay (TBIA). Seventeen plants from at least six independent transformations remained virus-free, whereas all control plants were infected with CymMV within 1 month. Further analysis by RT-PCR showed that the mut-11 mRNA was detectable in only two of these 17 plants. All plants were challenged again with a second CymMV inoculation as above, followed by TBIA analysis after 1 month. Thirteen of 17 plants remained free from virus. A third challenge of these plants with CymMV as above was followed by TBIA analysis at 1 week, 2 weeks, 1 month, 3 months, 6 months, and 12 months after challenge. Results at 2 weeks post-inoculation showed that all six controls and four individual transgenic plants, including the RT-PCR-positive plants, became systemically infected. Nine transgenic plants from both varieties remained free from CymMV 12 months after the third challenge. Lack of detectable mut11 mRNA in these resistant lines suggests that a post-transcriptional gene silencing (PTGS) mechanism may be conferring resistance to CymMV.
Elysia K. Krieger, Edwards Allen, Larry A. Gilbertson, James K. Roberts, William Hiatt, and Rick A. Sanders
), the accumulation of sense PG transcript should be unaffected and antisense transcripts would be detected. In contrast, if suppression were due to transcriptional or post-transcriptional gene silencing, accumulation of the message would be reduced
Jean-Michel Hily, Michel Ravelonandro, Vern Damsteegt, Carole Bassett, Cesar Petri, Zongrang Liu, and Ralph Scorza
, S. Bernstein, E. Beach, D. Hannon, G. 2000 An RNA-directed nuclease mediates post-transcriptional gene silencing in Drosophila cells Nature 404 293 296 Hannon, G.J. 2002 RNA
Zongrang Liu, Ralph Scorza, Jean-Michel Hily, Simon W. Scott, and Delano James
.J. Baulcombe, D.C. 1999 A species of small antisense RNA in post-transcriptional gene silencing in plants Science 286 950 952 Hamilton, A. Voinnet, O. Chappell, L. Baulcombe, D.C. 2002 Two
Ting Lei, Yang Song, Xuehua Jin, Tianyu Su, and Yiwen Pu
Endogenous post-transcriptional gene silencing of flavone synthase resulting in high accumulation of anthocyanins in black dahlia cultivars Planta 237 1325 1335 Deguchi, A. Tatsuzawa, F. Hosokawa, M. Doi, M. Ohno, S. 2015 Tobacco streak virus (strain dahlia
John R. Stommel, Gordon J. Lightbourn, Brenda S. Winkel, and Robert J. Griesbach
in length are involved in post-transcriptional gene silencing by targeting mRNAs for degradation via an endonuclease complex ( Baulcombe, 2004 ; Jones-Rhoades et al., 2006 ). Preliminary observations suggest that miRNAs could be involved in
Wenjing Guan, Xin Zhao, Richard Hassell, and Judy Thies
genes ( Lough and Lucas, 2006 ; Omid et al., 2007 ). Small interfering RNAs (siRNAs) mediate post-transcriptional gene silencing, a gene expression regulation mechanism involved in different layers of plant innate immunity ( Padmanabhan et al., 2009
Ying Fang, Ting Lei, Yanmei Wu, and Xuehua Jin
) suppresses post-transcriptional gene silencing of flavone synthase II in black dahlia cultivars and causes a drastic flower color change Planta 242 3 663 675 doi: 10.1007/s00425-015-2365-6 Deng, C.Y. Li, S.S. Feng, C.Y. Hong, Y. Huang, H