A new putative carlavirus identified by metagenomic analysis in a wild weed in Angola

A metagenomic analysis was performed by high-throughput sequencing (HTS) to identify viruses infecting a wild weed collected in Seles (Angola), which exhibited clear yellowing symptoms. The analysis led to the discovery of a putatively novel carlavirus, tentatively named 'Seles weed carlavirus'. The complete genome sequence, consisting of 8,597 nucleotides, poly-A tail excluded, exhibited the typical organization of members of the genus Carlavirus, including the replicase polyprotein (ORF1); the triple gene block (ORFs 2-4); the coat protein (ORF5) and an RNA-binding protein (ORF6). The replicase polyprotein and coat protein gene regions of the newly described virus shared the highest amino acid sequence identity with the corresponding sequences of cowpea mild mottle virus (51.40%) and Hainan betaflexivirus (63.08%), respectively. The infection was further confirmed by RT-PCR with multiple specific targeted primer pairs, whose related amplicons were cloned and sequenced.