Clematis vitalba Is a Natural Host of the Novel Ilarvirus, Prunus Virus I

Abstract

Clematis vitalba L. is a climbing shrub and a pioneer plant in abandoned orchards or vineyards that are widespread in temperate climate zones. In past years, several viruses infecting the Clematis species have been identified, including different ilarviruses. Prunus virus I (PrVI) is a recently described ilarvirus, which has been shown to infect sweet cherries and peaches in Greece. Moreover, its presence has been detected in ornamental Clematis in Russia. In the present work, we analyzed the virome of wildly growing C. vitalba plants from Hungary, Slovakia and Croatia showing different kinds of symptoms using high-throughput sequencing (HTS) of small RNAs or ribodepleted RNAs. Applying HTS enabled us to identify the presence of PrVI in C. vitalba, and the bioinformatic analyses were further validated with RT-PCR using PrVI-specific primers and Sanger dideoxy sequencing. Nearly full genome sequences of all three viral RNAs of one Hungarian, two Slovak and one Croatian isolate were determined. Their phylogenetic analysis showed high similarity to each other and to other PrVI isolates described from Central Europe. As the sampled plants were co-infected with other viruses, it is not possible to determine a direct correlation between the infection with PrVI and the observed symptoms. Analyses of different Prunus species in stock collection showed infection of several peach and sweet cherry varieties in Hungary. Our results expand the knowledge on the natural host range of PrVI and highlight the necessity to evaluate alternative plant hosts (even non-Prunus) of PrVI and the role of the virus in the etiology of the potential diseases.

Metagenomic analysis reveals the presence of prunus virus I in diseased Clematis vitalba: first record of this virus in Italy

“…The recent discovery of PrVI in Italy described in the present study, although associated with different symptoms in C. vitalba plants from those described on the same host by previous authors (Chirkov et al, 2022;Salamon et al, 2023), confirms that this plant is an important natural host for this virus. Since PrVI was only recently described, it is not clear what is its diffusion in nature or its impacts on cultivated plants.…”

“…Using HTS analysis, PrVI was first described on asymptomatic sweet cherry (Prunus avium) in Greece (Orfanidou et al, 2021), but was subsequently identified in the weed plant P. echioides (Rivarez et al, 2022) and repeatedly in Clematis spp. plants, mainly in Eastern Europe, including Hungary, Slovenia, Slovakia, Croatia and Russia (Chirkov et al, 2022;Rivarez et al, 2022;Salamon et al, 2023).…”