Molecular evidence for the occurrence of Pumpkin yellows virus (PuYV), a new polerovirus species associated with pumpkin plants

In India, cucurbit aphid-borne yellows virus, a cucurbit-infecting polerovirus, is emerging in the recent past with respect to its occurrence on different crops and geographical locations. This emphasized the need for an investigation to search for the possible occurrence of the other related species Polerovirus. In this view, different cucurbit hosts exhibiting severe chlorosis, bleaching, and yellowing symptoms were collected from the Vegetable Experimental Fields of IARI, New Delhi. The samples exhibiting yellowing and bleaching symptoms were associated with small isometric virions measuring ~ 25 nm under transmission electron microscope. The RT-PCR assays using generic (covering the partial RdRp , intergenic region and partial CP region) and complete coat protein (CP) gene-specific primers confirmed the association of a polerovirus. Further, complete CP gene sequence analyses revealed the association of a distinct species of Polerovirus with the pumpkin samples. These isolates showed the CP gene sequence identities below the species demarcation limit (90%) with the corresponding gene sequences of already reported polerovirus isolates. The results of this study provide the molecular evidence for the occurrence of a new species of Polerovirus , named tentatively as Pumpkin yellows virus (PuYV) in India.