An unwanted association: the threat to papaya crops by a novel potexvirus in northwest Argentina

Abstract

An emerging virus isolated from papaya (Carica papaya) crops in northwestern (NW) Argentina was sequenced and characterized using next-generation sequencing. The resulting genome is 6,667-nt long and encodes five open reading frames in an arrangement typical of other potexviruses. This virus appears to be a novel member within the genus Potexvirus. Blast analysis of RNA-dependent RNA polymerase (RdRp) and coat protein (CP) genes showed the highest amino acid sequence identity (67% and 71%, respectively) with pitaya virus X. Based on nucleotide sequence similarity and phylogenetic analysis, the name papaya virus X is proposed for this newly characterized potexvirus that was mechanically transmitted to papaya plants causing chlorotic patches and severe mosaic symptoms. RT-PCR based detection of papaya virus X (PapVX) revealed that it is widely present in papaya crops from NW Argentina. The prevalence of PapVX, which seems to be restricted to the NW region of Argentina, and the fact that it has only been detected in this region could be associated with a recent emergence or adaptation of this virus to papaya in NW Argentina.