الفهرس 
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Abstract
Isolation and identification
1- The virus was isolated from naturally infected faba bean plants.
2- The studied viruswas identified as BYMV according to symptomology, host range, virus stability, modes of transmission, ELISA and RT-PCR.
3- Host range of Bean yellow mosaic potyvirus (BYMV) was restricted to leguminosae to family leguminosae (Cicer arietinum, Lupinus termis, Phaseolus vulgaris, Trifolium alexandrinum and Vicia faba) and some members of Chenopodiaceae (Chenopodium album, C. amaranticolor and C. quinoa).
4- Dilution end point was 10-4.Thermal inactivation point was 65°C. The infectivity was retained at room temperature (25°C) for 3 days.
5- BYMV was mechanically transmitted to faba bean plants grown undr greenhouse conditions with 95% efficiency.
6- Myzus persicae and Aphis fabae were able to transmit BYMV from infected faba bean plants to healthy faba bean plants. The efficiency of transmission of the studied BYMV by Myzus persicae and Aphis fabae were 80% and 40%, respectively.
7- ELISA test confirmed the presence of BYMV in all the collected leaf samples at different times after inoculation.
8- Total RNA was extracted from healthy and infected faba bean plants.
9- Complementary DNA (cDNA) of BYMV was synthesized using reverse transcription reaction.
10- A fragment of coat protein gene (352 bp) was amplified using PCR.
Effect of bean yellow mosaic virus on faba bean growth and yield
Growth and yield characters were significantly lower in infected faba bean plants compared with healthy faba bean plants.
Induction of systemic resistance against bean yellow mosaic virus by plant extracts
1- Disease severity and BYMV titre were significantly reduced in faba bean plants treated with extracts of Cinnamomum zeylanicum bark (CZ), Syzygium aromaticum, Matericaria chamomilla L., Foeniculum vulgare, Zingiber officinale before or after BYMV inoculation.
2- The expression of pathogensis- related genes (PR1 and PR2) were significantly increased in faba bean plants treated with plant extracts compared with the control. These results explain the role of PR1 and PR2 genes in enhanced resistance against BYMV by plant extracts.