ISOLATION, CHARACTERIZATION AND PRESERVATION OF SOME PLANT VIRUSES

Abstract

Two plant viruses from pepper (Capsicum annuum) and tomato (Lycopersicon esculentum) were isolated and identified. The virus isolated from pepper transmitted mechanically and by Myzus persicae, but not through soil or seeds. Reaction of the virus with 34 hosts was investigated and data showed that it had narrow host range. The virus had flxious particles with 730 x 15 nm length. Thermal inactivation point was 55°C, dilution end point was 1 o-2 and longevity in vitro was 24 hr. The maximum UV absorbance of the virus particles was 0.512 at 260 nm and the minimum was 0.388 at 280 nm. Concentration of the virus after purification with polyethylene glycol, 6000 was 1.828 mg/ml. Data indicated that the virus is pepper mottle poty virus (PeMoV).

The virus isolated from tomato was easily mechanically inoculated and not aphid borne, soil borne and seed borne. The virus had a narrow host range. Thermal inactivation point was 60°C, dilution end point was 1o-3 and longevity in vitro was 6 hr. Data of ELISA technique confermed that the virus is tomato spotted wilt tospo virus (TSWV).

Different methods of preservation and storage of the two viruses were used and the results showed that preservation by lyophilization is the optimum method followed by dehydration of the infected plant tissue at the presence of calcium chloride.