First report of southern Tomato virus in tomato in the Canary Islands, Spain

In October 2006, tomato plants with torrado disease were sampled in Spain. In a sample of cv. Mariana, originating from Gran Canaria, Tomato torrado virus (ToTV, genus Torradovirus) was detected (isolate GCN06; Alfaro-Fernández et al., 2010). In 2013, the sample was further analysed using next-generation sequencing (NGS). Total RNA, extracted from ca. 150 mg of leaf tissues, was used for an RNA library suitable for Illumina HiSeq paired end sequencing. A de novo assembly (using CLC Genomic Workbench v.6.5) resulted in 1380 sequence contigs. BLAST searches revealed the presence of ToTV and Tomato chlorosis virus (ToCV, genus Crinivirus). One contig (3427 nts, 8901 reads), showed 99.85% identity with Southern tomato virus (STV, genus Amalgavirus), isolate Mexico-1 (GenBank accession No. EF442780), a dsRNA seed-transmitted virus (Sabanadzovic et al., 2009). Reference assembly with the Mexico-1 sequence resulted in a partial sequence of 3420 nts (GenBank KJ174690). The presence of STV in sample GCN06 was verified in RT-PCR using the specific primers STV-fw and STV-rev (Candresse et al., 2013) and sequencing of the obtained amplicon. A new sampling in May 2014 in Gran Canaria revealed the presence of STV in six out of seven tomato samples of cv Mariana. All these samples were co-infected with Pepino mosaic virus (PepMV, genus Potexvirus), Tomato spotted wilt virus (TSWV, genus Tospovirus), and Tomato yellow leaf curl virus (TYLCV, genus Begomovirus). Because STV was generally found in samples co-infected with other viruses, its symptomatology in tomato remains unclear. To our knowledge, this is the first report of STV in the Canary Islands and Spain