Molecular characterisation of a new tenuivirus from Festuca sp

Managing the deluge of newly discovered plant viruses and viroids: an optimized scientific and regulatory framework for their characterization and risk analysis

The advances in high-throughput sequencing (HTS) technologies and bioinformatic tools have provided new opportunities for virus and viroid discovery and diagnostics. Hence, new sequences of viral origin are being discovered and published at a previously unseen rate. Therefore, a collective effort was undertaken to write and propose a framework for prioritizing the biological characterization steps needed after discovering a new plant virus to evaluate its impact at different levels. Even though the proposed approach was widely used, a revision of these guidelines was prepared to consider virus discovery and characterization trends and integrate novel approaches and tools recently published or under development. This updated framework is more adapted to the current rate of virus discovery and provides an improved prioritization for filling knowledge and data gaps. It consists of four distinct steps adapted to include a multi-stakeholder feedback loop. Key improvements include better prioritization and organization of the various steps, earlier data sharing among researchers and involved stakeholders, public database screening, and exploitation of genomic information to predict biological properties.

A novel tenuivirus infecting wheat in Brazil

Since 1948, pale yellow wheat spike have been reported in southern Brazil. This symptom was associated with tenuiviruses due to the observation of cytoplasmic inclusions constituted by a mass of filamentous particles (7-10 nm in diameter) with indeterminate length, identical to those found in "leaf dip" preparations. Such symptoms are still seen in wheat crops; however, there is a lack of information regarding this pathosystem. Decades after the first report, the first sequences of wheat white spike virus were characterized. Wheat plants with symptoms such as pale yellowing, chlorotic streaks, and leaf mosaic were collected in Paraná State, Southern Brazil. High-throughput sequencing was used to determine the nearly complete nucleotide sequence of the viral genome. The genome is composed of five RNAs with a total size of 18,129 nucleotides, with eight open reading frames (ORFs). The virus identified in this study can be included in a new species in the family Phenuiviridae, genus Tenuivirus, and we have tentatively named this virus "wheat white spike virus".