USDA-ARS, Plant Genetic Resources Conservation Unit, Griffin, GA 30223
Universidade Federal de Rural Pernambuco, Recife, Brazil
Department of Plant Pathology, University of Georgia, Coastal Plain Experimental Station, Tifton 31793
The Brazilian strain of Cowpea aphid-borne mosaic virus (CABMV) is a severe pathogen in peanut and a significant problem when distributing germ plasm to other countries. The virus is seedborne at approximately 0.15% in peanut, depending upon the cultivar, and its detection in seed lots would strengthen quarantine programs. Utilizing 3′ sequence data (GenBank Accession #AF241233), primers were designed from the coat protein region and evaluated by reverse transcription-polymerase chain reaction (RT-PCR). Use of the forward primer 5′-CGCTCAAACCCATTGTAGAA-3′ and reverse primer 5′-TATTGCTTCCCTTGCTCTTTC-3′ yielded a 221-bp product. Extracts of thick seed slices and a sample size of 12 to 25 seed showed no significant advantage of RT-PCR over enzyme-linked immunosorbent assay (ELISA) in tests of large seed lots. However, RT-PCR detected more virus in seed than in the number of infected seedlings normally arising in germination tests. Also, RT-PCR was extremely sensitive and detected 1 infected leaf among 99 healthy leaves. In contrast, ELISA detected only one infected leaf among nine healthy leaves.