Molecular and biological properties of an endornavirus infecting winged bean (Psophocarpus tetragonolobus)

A double-stranded RNA (dsRNA) of approximately 15 kbp was isolated from asymptomatic winged bean (Psophocarpus tetragonolobus) plants. The size of the dsRNA, together with results of RT-PCR testing, suggested that it was the replicative form of a plant endornavirus. Cloning, sequencing, and sequence analyses confirmed the endornavirus nature of the dsRNA. Conserved motifs typical for endornaviruses were identified and their amino acid sequences compared with those of selected endornaviruses. Phylogenetic analyses revealed a close relationship with Bell pepper endornavirus, Phaseolus vulgaris endornavirus 2, and Hot pepper endornavirus. The dsRNA was present in most P. tetragonolobus genotypes tested. The virus was provisionally named Winged bean endornavirus 1 (WBEV-1).