Biological, serological and molecular studies on prunus necrotic ring spot virus infecting Rosa hybrida L. in Egypt

ABSTRACT

Prunus necrotic ring spot virus [PNRSV] was isolated for the first time in Egypt from naturally infected rose plants collected from the experimental farm of the Faculty of Agriculture, Cairo University. Observed symptoms circumvented necrotic ring spots on leaves, bud failure, and color breaking of petals. The virus was transmitted mechanically. The purified virus had Amax and A min at 260 and 240 nm respectively. The 260/280 ratio was 1.56. Yield of purified virus from infected Gompherina globosa was 0.182 mg/g tissue. Electron micrograph of the purified virus showed spherical [23-nm] as well as bacilliform virus particles [42x23 nm]. The induced antiserum from the purified virus was successfully used to detect PNRSV in rose plants in several locations in Egypt. The full length of the replicase gene of PNRSV was successfully amplified by reverse transcription-polymerase chain reaction [RT-PCR] using different sets of specific primers. A sensitive and specific IC-RT-PCR protocol was used for the detection of PNRSV from rose tissues. Sequence analysis of PNRSV/rep gene of the rose isolate indicated 60% similarity to that of PNRSV-AF278534 and NC-004362