Abstract

RNA silencing (RS) is a conserved eukaryotic mechanism acting in plants also as antiviral immune system. A successful virus infection requires suppression or evasion of host RS. Small interfering RNAs (siRNAs) are potent RS effectors, and accumulate in plants infected by RNA and DNA viruses as components of this plant immune system, providing targer specificity for pathogen RNA post-transcriptional degradation. Virus-derived siRNAs (vsiRNAs, 21-24 nt) are abundant and diverse in infected plants. Although any viral genomic regions can potentially be targeted to generating vsiRNAs, certain regions (also referred to as "hot spots") are more represented than others in vsiRNA sequenced libraries.Potato virus Y (PVY, Potyviridae) is an important plant pathogen on solanaceous hosts. The two PVY isolates PVYC-to and PVY-SON41 induce very different disease phenotypes on tomato (Solanum lycopersicum), the former being responsible of leaf distortions and the latter inducing to mild symptoms. In this study, we applied combined in silico and molecular biological approaches to identify PVY vsiRNAs putatively able to suppress host mRNAs by sequence complementarity and deriving RS-based suppression, a mechanisms that would induce dysfunctional processes in infected host plants. As the final aim of the study, we explored differential expression of specific host-targeting vsiRNA by the two isolates as one of the possible sources of diverse disease phenotype expression.A computational pipeline was implemented to retrieve 21nt vsiRNAs from PVY isolates, complementary to tomato predicted mRNAs (Solgenomics, ITAG2.3). The comparative study used NCBI blast+ package 2.2. RandFold searched secondary structures in the PVY RNA genome containing putative vsiRNAs sequences identified in previous steps.Two PVYC-to regions showed potential tRNA-like or microRNA-like secondary structures, not present in the other isolate, possibly accounting for vsiRNAs accumulation "hot spots". Moreover, we obtained two lists of tomato transcripts perfectly or imperfectly (one or two mismatches were allowed, according to typical microRNA recognition sites) complementary to vsiRNA computed for either of the two PVY isolates, and therefore putative target of vsiRNA-driven RS suppression. Putative targets common to the two isolates were discarded, so to identify a list of genes that could represent targets specific to the aggressive isolate PVYC-to only. Some host transcription factors (e.g. NAC, MYB, TCP, HD-ZIP, MADS-box families) active in vegetative development and leaf morphogenesis were selected for further investigation. Quantitative RT-PCR showed differential expression levels of selected host transcripts upon PVYC-to and PVY-SON41 infections, differing also from healthy plants. For some genes, lower isolate-specific mRNA accumulation suggested RS-driven post-transcriptional regulation, thus apparently confirming the starting hypothesis of a correlation between symptoms and RS

Autore Pugliese

• Finetti Sialer Mariella Matilde , Catalano Domenico , Cillo Fabrizio

Tutti gli autori

• Finetti-Sialer M.M.; Catalano D.; Cillo F.

Titolo volume/Rivista

Non Disponibile

Anno di pubblicazione

2013

ISSN

Non Disponibile

ISBN

Non Disponibile

Numero di citazioni Wos

Nessuna citazione

Ultimo Aggiornamento Citazioni

Non Disponibile

Numero di citazioni Scopus

Non Disponibile

Ultimo Aggiornamento Citazioni

Non Disponibile

Settori ERC

Non Disponibile

Codici ASJC

Non Disponibile