Plum pox virus (PPV) a potyvirus in the family Potyviridae, is the etiologic agent of sharka, the worldwide most important and detrimental viral disease of stone fruits (genus Prunus). Although PPV was identified in Italy already in the 1970s and it has been largely reported in almost all Italian regions, a broad investigation and genetic characterization of PPV isolates was lacking in most of them, including Tuscany (Central Italy). To address this knowledge gap, in 2020 and 2021, field surveys were carried out in 80 commercial Tuscany orchards and a total of 690 leaf samples were collected from different Prunus species. PPV was identified in 25 and 12 peach and plum samples, respectively (more than 5% of tested samples), whereas no positive samples were reported in apricot. Eighteen of the 37 PPV positive samples showed mixed infections with other viruses and viroids, mostly Prunus necrotic ringspot virus in plum and peach latent mosaic viroid in peach. Molecular typing of PPV infected samples generated NIb/CP amplicons corresponding to PPV-Marcus (M) or PPV-Recombinant (Rec) strains. Furthermore, starting from the identification of eight PPV nucleotide sequences (among which five and two new PPV-M and PPV-Rec isolates, respectively), this study firstly identified the PPV-Mb subgroup in Italy, which was even prevalent than PPV-Ma. Finally, PPV-Rec isolates resulted phylogenetically close to Italian and Turkish isolates previously detected. Overall, the results here presented represent an important step to fill knowledge gaps about PPV in Tuscany, and we believe it may encourage other similar research to achieve more accurate data on PPV populations at both national and international levels.

Bois noir (BN), a disease of the grapevine yellows complex associated with 'Candidatus Phytoplasma solani' (CaPsol), represents a great threat in all wine growing areas worldwide. Several studies revealed that BN epidemiology is extremely complex, including multiple insect vectors and plant hosts. In the present work, a survey on putative CaPsol insect vectors along with molecular typing of CaPsol strains was conducted to in-depth investigate the BN epidemiology in a BN-affected vineyard in Greve in Chianti (the Chianti Classico area, the Tuscany region), where the role of Reptalus artemisiae in transmitting CaPsol to grapevine was previously hypothesized. No Hyalesthes obsoletus specimens were captured, while Reptalus. artemisiae and Neoaliturus. fenestratus were found largely prevalent. Real-time PCR assay detected CaPsol in 41% and 37.5% of N. fenestratus and R. artemisiae specimens, respectively. Molecular typing evidenced that R. artemisiae and N. fenestratus are infected by CaPsol strains carrying mainly the stamp sequence variant St10 and St5, respectively. Other insects (Philaenus spumarius, Dictyophara europaea, Psammotettix spp.), reported as CaPsol vectors to grapevine in North Italy and poorly present in Greve in Chiantithe examined vineyard, was found infected by CaPsol strains carrying mainly the stamp sequence variant St5. In a recent study, these strains were found as the most abundant in grapevines (St5 and St10) and weeds (St10) in the examined vineyardChianti Classico area. Such results were reinforced by nucleotide sequence analyses of secY gene. Based on this and previous evidence, reporting the CaPsol vectoring activity of both R. artemisiae and N. fenestratus, it is reasonable to suggest that two mainthe role of such insects cycles can be involved in BN epidemiology in the Chianti Classico area. : (i) grapevine -R. artemisiae -weeds for CaPsol strains carrying the stamp variant St10; (ii) grapevine -N. fenestratus (plus other insects with a minor role) for CaPsol strains carrying the stamp variant St5. Thus, Ffurther studies are necessary to prove the vectoring activity of CaPsol by R. artemisiae and N. fenestratus to grapevine and understand their ecological and epidemiological role in the vineyard agroecosystem, including CaPsol source plants (insect host plants)., investigate the role of weeds in 3 CaPsol transmission routes to grapevine, clarify if grapevine can act as reservoir plant for CaPsol acquisition for these putative vectors.

This correction is published as typesetter substituted word Reptalus with Rhodococcus in the article.Original article has been updated.

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