The virome of Freesia hyb. showing leaf necrosis syndrome identified by an NGS-based omics approach: search for new actors on the stage

Several different plant viruses have been suggested as possible causal agents of the necrosis syndrome of freesia, first described before 1970 in Northern Europe and still threatening freesia cultivation all over the world, producing severe symptoms. Until now, no etiological agents have been convincingly associated with the disease and, to address this issue, we planned to study the symptomatic freesia virome using a next generation sequencing (NGS) based approach. Leaves of freesia plants showing strong necrotic symptoms and collected in different years in Northern Italy were used for total RNA extraction; the associated virome was reconstructed using an ad hoc bioinformatics pipeline and Serratus-mediated comparisons with sequencing data available at the NCBI Sequence Read Archive database. Results, under validation by independent molecular methods, enlarged our knowledge regarding the possible virome of symptomatic freesia, highlighting the presence of an uncharacterized virus belonging to the Class Bunyaviricetes.