Another night at the museum: searching for traces of plant viruses using the virion-associated nucleic acid metagenomics approach. [P.21]

The overall purpose of this project was to retrieve plant virus sequences from preserved Mediterranean and tropical plant specimens currently held within European, American and African herbaria and use these to provide a temporal element to our viral diversity studies and to retrace the emergence and spread over the past 100 years of several Mediterranean and tropical plant virus species. More than 550 plant specimens were processed using the virion-associated nucleic acid (VANA) metagenomics-based approach. Illumina reads were cleaned up and de novo assembled. Several plant virus-related contigs were identified, including potyvirus-, alfamovirus-, luteovirus-, and foveavirus-related sequences. Interestingly, 26 contigs (31-362 nt in length) sharing high identity (83.9-100%) with Euphorbia ringspot virus were recovered from two Euphorbia caput-medusae specimens collected in South Africa in 1946 (22 contigs) and 1991 (4 contigs) and conserved in the Bolus Herbarium of Cape Town. The characterization of partial or complete genomes of these “ancient” potyvirus isolates is underway.