Proposal of the new species Coguvirus eburi

A novel virus has been identified in citrus and named citrus virus A (CiVA, Navarro et al., 2018a). CiVA is an RNA virus with a bisegmented genome: RNA1 (6691 nt) encodes the RNA-dependent RNA polymerase (RdRp, p250) in the viral complementary (vc) strand, while RNA2 (2740 nt) is a bicistronic ambisense RNA that encodes a putative movement protein (MP, p44) in the viral (v) strand and the nucleoprotein (NP, p42) in the vc strand. BlastP analysis identified the RdRp encoded by CCGaV as the closest related protein of CiVA p250 and multiple alignments revealed that this protein contains the typical six motifs (premotif A and motifs A-E) highly conserved in the RdRp core of members of the order Bunyavirales, showing the highest identity with CCGaV RdRp core. Pairwise analyses showed that CiVA and CCGaV RdRp share 78.48% amino acid (aa) sequence identity, while the sequence identity with the homologous protein of watermelon crinkle leaf-associated virus 1 (WCLaV-1) and watermelon crinkle leaf-associated virus 2 (WCLaV-2), two plant-infecting bunyaviruses reported recently and not yet classified, was lower (63,1% and 57,6%, respectively, Table 1). Also the CiVA MP and NP share the highest sequence identity with CCGaV (67.18 and 60.64%, respectively) and, to a lower extent, with the homologous proteins encoded by WCLaV-1 and WCLaV-2 . ML phylogenetic trees were generated using the conserved core of RdRp and the complete sequence of MP and NP of CiVA, CCGaV and other representative members of several genera in the order Bunyavirales. In these trees CiVA and CCGaV always clustered together in a clade clearly separated from the other bunyavirales. Based on these data, we propose to classify citrus virus A as a member of a novel species named Coguvirus eburi, in the genus Coguvirus.