Evaluation of Clitoria ternatea Flower Extracts as a Novel Method to Manage Bean Yellow Mosaic Virus (BYMV) infecting Faba Bean

Bean yellow mosaic virus (BYMV) is one of the most destructive viral diseases affecting leguminous crops, causing severe yield losses. This study aimed to evaluate the potential activity of Clitoria ternatea flower extracts both alcohol and aqueous at different concentrations as a novel method to manage BYMV infection in faba bean plants. The incidence of BYMV was recorded in four governorates (Fayoum, Beheira, Giza, and Bani Suef) during the 2022 growing season to determine the epidemiology of the virus, with infection rates ranging from14.4 to 46.4%. BYMV was isolated and identified based on the symptoms, host range and molecular techniques. Reverse transcription-polymerase chain reaction (RT-PCR) was used to detect BYMV, 54 out of 95 samples gave positive results, amplicons were approximately 907bp using specific BYMV primer and 335bp with degenerate primer. Sequence analysis of the Egyptian isolate (Accession No. PP481923) showed identity ranging from 90.8% to 98.3% compared with ten BYMV sequences in GenBank. Various treatments with C. ternatea flower extracts were applied. Results demonstrate that the application of C. ternatea extracts, particularly the alcohol extract in protective treatment at a concentration of 3% effectively eliminated virus-induced symptoms, improved growth parameters, and enhanced photosynthetic pigments in infected faba bean plants compared to the untreated infected control. These results were confirmed by real-time RT-PCR. The flower extracts haven’t been previously used to manage plant viruses, while they have been used to resist human viruses i.e. Coronaviruses. Using C. ternatea flower extracts is a promising eco-friendly and alternative control method against BYMV.