Squash leaf curl virus (SLCV) was isolated from naturally infected common bean
plants grown in Egypt. Symptomatic leaf samples were collected from bean fields
cultivated in different governorates and tested by PCR using Geminivirus degenerate
primers and Squash Leaf Curl Virus (SLCV) specific primers. All bean varieties grown in
surveyed governorates were found susceptible to Geminivirus infection and the dominant
Geminivirus affecting bean fields was SLCV. Percentage of infection was higher at Nili
season than that at the summer season. Six different commercial varieties of common
bean were evaluated for SLCV infection at three different growth stages. The evaluation
was performed using whitefly inoculation in insect proof green house. Two commercial
varieties (Tema and Giza 6) were found to be tolerant to SLCV infection in all tested
growth stages. The disease severity of the viral infection varied in the other four
susceptible varieties at the different growth stages. It was observed that infection
percentage and disease severity were decreased with increasing growth stage. A
significant difference in the percentage of yield loss in inoculated plants at age 15d and
25d from planting compared with control was recorded. On the other hand percentage of
yield loss in plants inoculated at 35d stage was non-significant. The coat protein gene of
SLCV was PCR amplified from infected common bean plants. SLCV-CP was cloned in
pJET cloning vector and directly sequenced. The sequence alignment and phylogenetic
analysis showed a relatively high diversity among the three different isolates that the
identity ranged from 89 to 94%.