Serological detection of seed borne viruses in cowpea regenerated germplasm using protein a sandwich enzyme linked immunorsorbent assay

Abstract

Cowpea (Vigna unguiculata (L.) Walp) is susceptible to a number of fungal, bacterial and viral diseases. The effects of viruses can be devastating and are a major constraint to the production of cowpea. A study was carried out to detect the presence of seed borne viruses in fourteen cowpea accessions screened from 300 regeneratedcowpea germplasm from the genebank collection of the International Institute of Tropical Agriculture (IITA) in Nigeria. Protein A Sandwich Enzyme linked Immunosorbent Assay (PAS ELISA) was used to detect seed borne viruses in the accessions. Out of 36 accessions of TVu 033 indexed, 31 were infected with Cowpea aphid-borne mosaic virus genus Potyvirus, which is of great economic importance in germplasm conservation and exchange between countries as it causes great loss. Southern bean mosaic virus was not detected in any of the accessionsevaluated. Seeds were harvested from the infected mother plants at maturity and the embryos excised in vitro onto hormone free medium composed of 4.43 g MS basal salt, 30 g sucrose and 8 g of agar. The seedlings obtained were serologically indexed to detect any seed-borne viruses after acclimatisation to screen house conditions. Theseedlings obtained from excised embryos got from harvested seeds gave a negative ELISA result.