Abstract

Potato virus Y (PVY) is one of the most important pathogens of pepper, potato, tobacco,tomato and other solanaceous and non-solanaceous hosts. Two PVY isolates, PVY-Cto and PVYSON41,induce very different disease phenotypes on tomato (Solanum lycopersicum), the formerbeing responsible of leaf distortions and growth reduction and the latter inducing only very mildsymptoms. With the aim of investigating the role of RNA silencing mechanisms in the differentpathogenic behaviour of the two isolates, we performed a systematic analysis of expression profilesof Dicer-like (DCL), Argonaute (AGO) and RNA-dependent RNA polymerase (RDR) genes thatform the core components of the RNA silencing-based plant immune system. The effects onexpression profiles of some of these genes were significantly higher in tomato plants infected by theaggressive isolate PVY-Cto in comparison with PVY-SON41-infected and healthy plants.We further investigated on whether effects on expression of silencing genes could lead to adifferential accumulation of small RNAs (sRNAs) in plants. Both endogenous microRNA (miRNA)and viral small interfering RNA (vsiRNA) populations were analysed by high-throughputsequencing. SRNAs from tomato plants, healthy or infected by PVY-Cto and PVY-SON41, wereisolated at 21 and 30 days post-inoculation (dpi) and sequenced using the Illumina platform at theNGS Laboratory, IGA (Udine, Italy). Total reads from samples at 21 dpi ranged between 13 to 17million, and at 30 dpi between 23 to 28 million. From these data, vsiRNA and miRNA populationswere analysed separately. VsiRNA from PVY-Cto-infected samples were abundant andcorresponded to 44% and 29% of total reads at 21 and 30 dpi, respectively. Surprisingly, anegligible number of vsiRNA were found in PVY-SON41-infected samples, representing less than1% of total reads at both timepoints.As expected, virus infection affected also the composition of the miRNAome. The totalnumber of sRNAs corresponding to known plant miRNAs was proportional to each library size andvaried in a narrow range from 2.8 % ot total reads in mock-inoculated at 21 dpi to 4,8% in PVY-Ctosamples at the same timepoint. A total of 156 known miRNA was identified in the six libraryfollowing stringent criteria. To compare miRNA abundance in different libraries, the count of eachmiRNA was normalized to transcripts per million (TPM) and subjected to a Z-test. Change inmiRNA read counts between virus- and mock-inoculated plants was scored as fold change andrecorded. On this basis, PVY-Cto infection was associated to the differential accumulation (eitherup- or downregulated) of 71 and 39 miRNA at 21 and 30 dpi, respectively. The mild PVY-SON41 isolate affected the composition of miRNA population at significantly lower extent, and adifferential accumulation was observed only for 25 (21 dpi) and 6 (30 dpi) miRNAs.Our results provide a comparative analysis, via deep sequencing, of changes i

Autore Pugliese

• Finetti Sialer Mariella Matilde , Cillo Fabrizio

Tutti gli autori

• Finetti-Sialer M.M.; Catalano D.; De Paola D.; Tecce T.; Cillo F.

Titolo volume/Rivista

Non Disponibile

Anno di pubblicazione

2014

ISSN

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ISBN

978-88-904570-4-3

Numero di citazioni Wos

Nessuna citazione

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Settori ERC

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