Bean common mosaic virus strain blackeye cowpea mosaic (BCMV-BICM), a unique and commercially significant virus that naturally infects cowpea plants and displays a range of symptoms such as mosaic or mottling, vein clearing, vein banding, blistering, necrosis, yellowing, and leaf malformation was obtained from the experimental farm of the Agricultural Research Center in Giza, Egypt during the 2018–2019 growing season. The goal of this research is to identify BCMV-BICM utilizing biological, serological, histological, cytological, and molecular methods. By studying the host range, BCMV-BICM infects just eight plant species and cultivars out of twenty-four plant species and cultivars belonging to four families. The proportion of aphis transmission of BCMV-BICM was 40%. Seed transmission varied from 5% to 8% in the three cultivars evaluated. BCMV-BICM only responded favorably with specific antisera against BCMV in a direct enzyme-linked immunosorbent assay. Light microscopy revealed amorphous cytoplasmic inclusions generated by BCMV-BICM in cowpea leaf strips. The findings clearly established structural differences between cowpea plants infected with BCMV-BICM and healthy plants (control). The electron microscopy of cleared infected cowpea extract stained negatively with 2% phosphotungstic acid exhibited filamentous flexuous particles with a length of 720–750 nm. Reverse transcription-polymerase chain reaction (RT-PCR) analysis and sequencing of RT-PCR products were used to determine the identity of the virus. This is the first report of a BCMV-BICM isolate found spontaneously in Egyptian cowpea plants.
Key words: BCMV- BICM, ELISA, Microscopy, RT-PCR and Sequencing
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