Molecular Detection and Characterization of Melon Yellow Spot Virus in Cucurbit Crops Using Serological Methods

Abstract

Severe yellow spotting, chlorotic lesions, mosaic symptoms, and leaf deformation were observed in cucurbit crops cultivated under open-field and protected production systems, suggesting infection by a viral pathogen. Symptomatic leaf samples collected from major cucurbit-growing areas were analyzed for the detection and characterization of Melon yellow spot virus (MYSV) using integrated serological and molecular diagnostic approaches. Initial screening through enzyme-linked immunosorbent assay (ELISA) confirmed the presence of viral antigens in a high proportion of symptomatic samples, whereas healthy plant tissues tested negative. Total RNA extracted from infected plants was subjected to reverse transcription polymerase chain reaction (RT-PCR) using virus-specific primers targeting conserved genomic regions. Amplification of the expected DNA fragments confirmed the association of MYSV with symptomatic cucurbit plants. Sequencing and comparative nucleotide analysis revealed high genetic similarity between the obtained isolates and previously reported MYSV isolates from different geographic regions. Phylogenetic analysis clustered the isolates within established MYSV lineages, indicating close evolutionary relationships among regional and international populations. Disease incidence was markedly higher in fields with elevated thrips populations, supporting the epidemiological role of insect vectors in virus transmission and dissemination. Environmental conditions characterized by warm temperatures and intensive cucurbit cultivation favored disease spread and symptom expression. Variability in symptom severity among cucurbit species suggested differential host susceptibility to the virus. Rapid and reliable identification of MYSV through combined serological and molecular methods provides essential support for disease surveillance, quarantine monitoring, and implementation of timely management strategies.