Abstract

Comparative study of dilution end point on various detecting enzymes in ELISA techniques to determine sensitivity level for detection of Maize Steak Virus (MSV), both in the maize plant and the insect vector Cicadulina mbila (leafhopper), was carried out using Alkaline phosphatase (ALP), Horseradish peroxidase (HRP), Alkaline phosphatase amplification (AMP) and Penicillinase (PNC) and Avidin- Biotin Penicillinase amplification  based ELISA. Assays with the PNC-based ELISA were as sensitive as analogous assays performed with ALP and HRP for the virus in infected maize plant. The HRP and the Penicillinase- based ELISA were able to detect virus in three and crushed leafhoppers respectively. Only the Avidin- Biotin Penicillinase amplification technique was able to detect viruses in one single leafhopper.  As expected, the ALP and the alkaline phosphatase enzymatic amplification systems were not useful in virus detection in the insect vector due to the high background of the healthy leafhoppers. This could be due to insects containing their own phosphatase stem. The protein A coat Penicillinase technique was not useful due to non specific reaction.

Key words: Enzyme Linked Immunosorbent Assay, maize streak virus, Cicadulina mbila, alkaline phosphatase, alkaline phosphatase amplification, horseradish peroxidase, penicillinase based ELISA.