Biology subjects

Ciuffo, M.

Publications and source records attributed to Ciuffo, M..

3 recordsLinked to original sources

bioRxiv2026

A tomato fruit blotch viral replicon defines minimal requirements for cell autonomous replication and identifies functional RNA4-encoded movement and silencing suppression activities

Tomato fruit blotch virus (ToFBV) is an emerging multipartite positive-sense RNA virus associated with blotchy symptoms on tomato fruits and classified within the genus Blunervirus (family Kitaviridae). Despite its increasing agricultural relevance, the study of ToFBV has been hindered by the lack of mechanical transmissibility and the difficulty in reproducing infections under controlled conditions. In this work, we report a preliminary step toward the development of the first infectious agroclone system for ToFBV, based on full-length cDNA copies of its four genomic RNAs. We demonstrate that the cloned viral genome is capable of initiating cell autonomous replication in Nicotiana benthamiana, as indicated by the accumulation of negative-sense RNA intermediates in infiltrated tissues. To further validate the system, RNA3 was engineered to express GFP, enabling visualization of infection foci and confirming active viral replication in both N. benthamiana and tomato. Functional assays of RNA4-encoded proteins demonstrated that it encodes a movement protein capable of complementing movement-deficient viral vectors and a putative suppressor of post-transcriptional gene silencing (PTGS). Together, these results establish a versatile reverse genetics platform for ToFBV, providing new insights into the replication and functional organization of blunerviruses and enabling future studies on virus-host interactions, pathogenicity, and control strategies

microbiology↗

bioRxiv2024

Monitoring the directed evolution to a tripartite genome from a bipartite torradovirus genome

We have previously shown that tomato apex necrosis virus that cannot express the RNA2-ORF1 protein (P21) is not able to systemically infect plant hosts but is not affected in cell autonomous aspects of virus replication/accumulation. Here we attempted to provide P21 in trans by co-agroinfiltrating the RNA2-ORF1 null constructs (a stop codon mutant and a deletion mutant) with a P21-expressing construct under control of the 35S promoter and containing the 5 and 3 UTRs of wild type (WT) RNA2. Such construct when co-agroinfiltrated with the stop codon mutant originates a WT bipartite virus through homologous recombination. More surprisingly, when co-agroinfiltrated with the P21 deletion mutant it cannot immediately complement the mutant, but it serendipitously originates a tripartite virus with an actively replicating P21-expressing RNA3 only after this replicating RNA3 accumulates deletions in a small region inside the original 3-UTR provided by the cDNA clone. Such virus can be transmitted mechanically and by whiteflies, is competent for virion formation, and its RNA3 is encapsidated. The tripartite virus can be mechanically transferred for eleven generations without losing its infectivity or show major genomic rearrangements. Furthermore, mixing equal amounts of WT and tripartite virus inocula in the same leaf originated plants systemically infected only with the WT virus, showing that the tripartite virus has lower fitness than the WT. To our knowledge this is the first example of a stable virus evolving in vitro from bipartite to tripartite genomic structure from a synthetic construct in a plant virus.

microbiology↗

bioRxiv2019

A complex virome that includes two distinct emaraviruses is associated to virus-like symptoms in Camellia japonica

Camellia japonica plants manifesting a complex and variable spectrum of viral symptoms like chlorotic ringspots, necrotic rings, yellowing with necrotic rings, yellow mottle, leaves and petals deformations, flower color-breaking were studied since 1940 essentially through electron microscopic analyses; however, a strong correlation between symptoms and one or more well characterized viruses was never verified. In this work samples collected from symptomatic plants were analyzed by NGS technique and a complex virome composed by viruses members of the Betaflexiviridae and Fimoviridae families was identified. In particular, the genomic fragments typical of the emaravirus group were organized in the genomes of two new emaraviruses species, tentatively named Camellia japonica associated emaravirus 1 and 2. They are the first emaraviruses described in camellia plants and were always found solely in symptomatic plants. On the contrary, in both symptomatic and asymptomatic plants, we detected five betaflexiviruses isolates that, based on aa identitiy comparisons, can be classified in two new putative species called Camellia japonica associated betaflexivirus 1 and Camellia japonica associated betaflexivirus 2. Together with other recently identified betaflexiviruses associated to Camellia japonica disease, the betaflexiviruses characterized in this study show an unusual hyper-conservation of the coat protein at aminoacidic level.

microbiology↗