Molecular evidence for the occurrence of cucurbit yellow stunting disorder virus (CYSDV) infecting round melon and wild melon in India.

Abstract

Cucurbit yellow stunting disorder virus (CYSDV), has recently been detected in different crops in India, including cucumber, bitter gourd, and watermelon. To investigate the distribution of emerging criniviruses, symptomatic round melon and wild melon plants were analyzed through transmission electron microscopy and RT-PCR. Long filamentous virions (~ 850 nm in length) resembling criniviruses and ~ 550 bp amplicons of RdRp gene specific to the genus Crinivirus were observed. The phylogeny using coat protein gene amino acid sequences of different criniviruses revealed grouping of round melon and wild melon isolates of this study with CYSDV isolates originating from Mexico. These isolates exhibited up to 100% amino acid sequence homology with other previously reported CYSDV isolates worldwide. Further, the associated virus was transmitted successfully to the healthy cucumber test plants in the whitefly-based bio-assay. Results of this study confirm the association of CYSDV in round melon and wild melon plants for the first time in India, highlighting the virus's rapid geographic and host range expansion. The findings emphasize the urgent need for strategies to manage and mitigate the spread of this devastating virus.