Abstract

The study focused on the molecular and biological characterization of OYVMV which helps to understand its transmission efficiency along with genetic diversity and impact on okra varieties. Four okra varieties viz., Sabz Pari, Ujala, Sultan-121, and BS728 were verified for the presence of OYVMV pathogen via grafting and insect transmission in biological characterization while PCR was used to detect the presence in molecular characterization. Three- to four-week-old plants were divided into two groups: one inoculated using an insect vector and the other through grafting with PCR-confirmed infected leaf samples. Both groups were compared with the plants used as control for respective transmission studies. The results indicated that grafting was a more efficient transmission method having varied degree of severity for different indicator plants. whereas insect vector transmission showed variability. Virus transmission studies conducted under in vitro conditions through whitefly and grafting showed 73.66% and 90% transmission efficiency on “Sultan-121” respectively at 7, 15, and 21 days post-inoculation. Molecular characterization through PCR and gel electrophoresis confirmed the presence of OYVMV with distinct amplified fragments validating viral presence in the infected samples. Sequence analysis of these amplified DNA fragments showed that the OYVMV isolates from these districts share more than 90% genetic homology with previously reported Pakistani strains and have over 85% similarity with isolates from neighboring countries, including India, Bangladesh, Sri Lanka, Malaysia, and China. The study reported that variations in the disease symptoms, incidence and severity were there but not significant in relationship to virus isolates in four geographical locations (Districts). These findings confirm the widespread presence of OYVMV in Pakistan providing critical insights into its transmission mechanisms and genetic structure.