The involvement in viroid-host interactions of RNA silencing, an RNA-based network regulating gene expression and defense against invasive nucleic acids in most eukaryotes, is supported by the accumulation in tissues infected by nucleus- and chloroplastreplicating viroids of viroid-derived small RNAs (vd-sRNAs) of 21-24 nt, structurally similar to host microRNAs (miRNAs) and small-interfering RNAs (siRNAs). Based on these findings it was proposed that vd-sRNAs, similarly to miRNAs, might target host mRNAs for degradation (or translation inhibition), thus leading to symptom expression in the infected plants. In the last few years, using high-throughput technologies, we have characterized the vdsRNAs derived from a chloroplast-replicating viroid [Peach latent mosaic viroid (PLMVd)]. Moreover, by semi-quantitative RT-PCR and RNA ligase-mediated rapid amplification of cDNA ends, we have shown that two vd-sRNAs (containing the patogenicity determinant strictly associated with an albino phenotype) target for degradation a host mRNA, thus providing the first experimental evidence that, indeed, vd-sRNAs function like miRNAs. Interestingly, the targeted mRNA codes for a protein (cHSP90) involved in chloroplast biogenesis, which is the developmental pathway specifically compromised in the albino tissues infected by PLMVd variants generating the two vd-sRNAs (Navarro et al., 2012. The Plant Journal 70: 991-1003). Altogether these data strongly support the involvement of RNA silencing in PLMVd pathogenesis and, possibly, a more general role of vd-sRNAs in modulating host gene expression during viroid infection. For a deeper insight into this question, we have integrated data from high-throughput sequencing of vd-sRNAs accumulating in tissues infected by chloroplast- and nucleus-replicating viroids with the respective degradome analyses. Based on experimental data, the implications will be discussed of the RNA degradation patterns potentially elicited by vd-sRNAs during viroid infection.
Dissection of viroid-host interplay by deep sequencing of small RNA libraries and degradome analyses
Navarro B;Gisel A;Di Serio F
2013
Abstract
The involvement in viroid-host interactions of RNA silencing, an RNA-based network regulating gene expression and defense against invasive nucleic acids in most eukaryotes, is supported by the accumulation in tissues infected by nucleus- and chloroplastreplicating viroids of viroid-derived small RNAs (vd-sRNAs) of 21-24 nt, structurally similar to host microRNAs (miRNAs) and small-interfering RNAs (siRNAs). Based on these findings it was proposed that vd-sRNAs, similarly to miRNAs, might target host mRNAs for degradation (or translation inhibition), thus leading to symptom expression in the infected plants. In the last few years, using high-throughput technologies, we have characterized the vdsRNAs derived from a chloroplast-replicating viroid [Peach latent mosaic viroid (PLMVd)]. Moreover, by semi-quantitative RT-PCR and RNA ligase-mediated rapid amplification of cDNA ends, we have shown that two vd-sRNAs (containing the patogenicity determinant strictly associated with an albino phenotype) target for degradation a host mRNA, thus providing the first experimental evidence that, indeed, vd-sRNAs function like miRNAs. Interestingly, the targeted mRNA codes for a protein (cHSP90) involved in chloroplast biogenesis, which is the developmental pathway specifically compromised in the albino tissues infected by PLMVd variants generating the two vd-sRNAs (Navarro et al., 2012. The Plant Journal 70: 991-1003). Altogether these data strongly support the involvement of RNA silencing in PLMVd pathogenesis and, possibly, a more general role of vd-sRNAs in modulating host gene expression during viroid infection. For a deeper insight into this question, we have integrated data from high-throughput sequencing of vd-sRNAs accumulating in tissues infected by chloroplast- and nucleus-replicating viroids with the respective degradome analyses. Based on experimental data, the implications will be discussed of the RNA degradation patterns potentially elicited by vd-sRNAs during viroid infection.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
