Exploring the tymovirales landscape through metatranscriptomics data.

Area of Science:

• Virology
• Plant Pathology
• Bioinformatics

Background:

• The order Tymovirales comprises positive-sense RNA viruses predominantly infecting plants, fungi, and insects.
• High-throughput sequencing has accelerated the discovery of new viral genomes within this taxon.
• Publicly available transcriptomic data represents a largely untapped resource for virus discovery.

Purpose of the Study:

• To discover novel viral genome sequences within the order Tymovirales.
• To analyze the genomic organization and phylogenetic relationships of newly identified viruses.
• To demonstrate the utility of public Sequence Read Archive (SRA) data for virus discovery.

Main Methods:

• Homology searches were performed on over 3,000 plant transcriptomes from the NCBI SRA using known tymovirales sequences.
• Raw SRA reads were identified, assembled, and curated to obtain viral genome sequences.
• Phylogenetic analysis was conducted to determine the relationships of the novel viruses to existing tymovirales groups.

Main Results:

• Thirty-one novel viral genome sequences were identified from 27 different host plant species.
• Twenty-nine complete coding regions and two partial genomes were obtained.
• Phylogenetic analysis placed six viruses with alphaflexiviruses, 17 with betaflexiviruses, two with deltaflexiviruses, and six with tymovirids.

Conclusions:

• The analysis of public SRA data is a powerful method for accelerating virus discovery.
• The newly discovered viruses reveal novel genome organizations and expand our understanding of tymovirales diversity.
• These findings provide new insights into the phylogenetic relationships and evolutionary dynamics of the Tymovirales order.