Résumé
A metagenomic study was conducted to identify viruses present in 180 leaf samples of Saccharum species collected in 2013/2014 from plants in commercial fields in the Everglades Agricultural Area and the germplasm collection of the USDA-ARS Sugarcane Field station at Canal Point, FL. The objective of this study was to identify known and potentially new sugarcane viruses. In addition to previously reported sugarcane viruses in Florida, we identified the presence of a potential new Mastrevirus species. Since there are no Mastrevirus species reported from Florida, and species in this genus such as Sugarcane streak virus and Maize streak virus are known to cause diseases in sugarcane, efforts were made to obtain full length viral genome sequences from individual plants of Saccharum spp. Rolling circle amplification followed by enzymatic restriction and cloning was used to obtain nine full genome length sequences (each approximately 2.8 kb): three from S. barberi, two from S. officinarum and four from S. spontaneum, all from the germplasm collection. All nine genome sequences appeared to represent a new species of Mastrevirus after their pairwise comparison using the species demarcation tool (SDTversion1.2). Sequence similarity among sequences also suggested the presence of two strains of this new virus. This new species was found in plants that were introduced to Florida more than six decades ago. (Texte integral)