Virus-derived transgenes expressing hairpin RNA give immunity to Tobacco mosaic virus and Cucumber mosaic virus

Abstract

BackgroundAn effective method for obtaining resistant transgenic plants is to induce RNA silencing by expressing virus-derived dsRNA in plants and this method has been successfully implemented for the generation of different plant lines resistant to many plant viruses.ResultsInverted repeats of the partial Tobacco mosaic virus (TMV) movement protein (MP) gene and the partial Cucumber mosaic virus (CMV) replication protein (Rep) gene were introduced into the plant expression vector and the recombinant plasmids were transformed into Agrobacterium tumefaciens. Agrobacterium-mediated transformation was carried out and three transgenic tobacco lines (MP16-17-3, MP16-17-29 and MP16-17-58) immune to TMV infection and three transgenic tobacco lines (Rep15-1-1, Rep15-1-7 and Rep15-1-32) immune to CMV infection were obtained. Virus inoculation assays showed that the resistance of these transgenic plants could inherit and keep stable in T4 progeny. The low temperature (15℃) did not influence the resistance of transgenic plants. There was no significant correlation between the resistance and the copy number of the transgene. CMV infection could not break the resistance to TMV in the transgenic tobacco plants expressing TMV hairpin MP RNA.ConclusionsWe have demonstrated that transgenic tobacco plants expressed partial TMV movement gene and partial CMV replicase gene in the form of an intermolecular intron-hairpin RNA exhibited complete resistance to TMV or CMV infection.

Tilting the balance between RNA interference and replication eradicatesLeishmaniaRNA virus 1 and mitigates the inflammatory response

“…In other organisms, sRNA/siRNA levels provide a gauge of RNAi pathway recognition and targeting of viruses: When RNAi controls virus replication, as in plants, fungi, and insects (26,32,33), high levels of siRNAs accompany viral infections, leading to eradication of the virus. In mammals, quantitatively fewer siRNAs are present, which do not effectively control virus levels, at least in adult somatic tissues (34,36,37).…”

“…The RNAi pathway converts double-stranded RNA into siRNAs, which trigger the degradation of an mRNA with complementary sequence (31). Importantly, the RNAi pathway acts as a defense against RNA viruses in plants and some animals, leading to great reductions or complete elimination (32,33). Further, introduction of RNAi pathway proteins from Saccharomyces castellii into the naturally RNAi-null S. cerevisiae resulted in greatly decreased levels of persistently infecting L-A totivirus (26).…”

Stability of Transgenic Resistance Against Plant Viruses

“…Moreover, tomato plants carrying an IR construct derived from Potato spindle tuber viroid (PSTVd) sequences and exhibiting resistance to PSTVd infection, did not show an elevated IR-siRNA accumulation at 31°C in comparison to 21°C (Schwind et al, 2009). In a more recent study, transgenic tobacco plants transformed separately with IR constructs corresponding to sequences of TMV movement protein gene or CMV replication protein gene, exhibited at both 15°C and 24°C similar high levels of resistance to TMV or CMV, respectively (Hu et al, 2011). In addition, the resistance against TRV of transgenic tobacco plants (Vassilakos et al, 2008) grown at 15°C was influenced only in the inoculated leaves but not systemically (Vassilakos, unpublished results).…”

“…The effectiveness of the resistance was not detectably compromised even following co-infection with all five viruses. Most recently, transgenic tobacco plants were produced, transformed with an IR construct corresponding to sequences of the TMV movement protein gene and the exhibited resistance to TMV was not affected by infection with CMV regardless of the order that the latter was inoculated (prior to or simultaneously with TMV) (Hu et al, 2011). In a different approach, amiRNAs expressed in tomato plants against CMV coding sequences resulted in resistance against the virus which was not noticeably affected by infection with TMV or TYLCV .…”

Ingeniería genética vegetal para resistencia viral y vectores virales en genética reversa

“…La transformación de plantas con construcciones ARN hairpin además ha sido usada para descubrir o validar la función de los genes , pero también son valiosas en genética reversa, genómica e ingeniería de rutas metabólicas (Smith et al, 2000;Chen et al, 2006;Sliva and Schnierle, 2010). Estas construcciones génicas que contienen casetes de expresión de repetidos invertidos son mucho mas eficientes que el silenciamiento mediado por construcciones sentido o antisentido (Hu et al, 2011).…”