SEROLOGICAL AND MOLECULAR BIOLOGY STUDIES ON WATERMELON MOSAIC VIRUS IN EGYPT AND MOROCCO

Abstract

An isolate of WMV obtained from commercial fields in Qualubya

Governorate (Qualub and Toukh). The observed symptoms included yellowing, severe mosaic, green blisters, vein clearing, malformation,

and foliar distortion with small fruits.

Reaction of sixty plant species and varieties belonging to ten different families was tested; the virus reacted positively with twenty seven plants. The virus had dilution end point of 10-4 - 10-5, thermal inactivation point of 60 - 65°C /10 min and ageing in vitro (20- 25°C) lay

between 15 and 20 days. The virus was transmitted by Myzus persicae, Aphis gossypii and Aphis craccivora, the percentages of transmission were 80 %, 50 %, and 30 % respectively. WMV was purified with a high degree of purity with a minimum at 245 nm and a maximum at 260nm. • The A 2601280 and a max I min rations were 1.11 and 1.01 respectively.

The estimated yield of the purified virus was 3.88 mg/1 OOg. The virus had filamentous rod-shape particles ranged from 730 - 750 nm in length and 15 nm in width. The polyclonal antibodies developed against WMV obtained after the third bleeding (1/2048) were used in purification of lgG and conjugation of lgG with alkaline phosphatase. The optimum concentration of lgG and lgG conjugate for ELISA was 0.5 µg /ml and 1/2000, respectively.