VIEW ARTICLE

Etiology

Differentiation Among Garlic Viruses in Mixed Infections Based on RT-PCR Procedures and Direct Tissue Blotting Immunoassays. Tadamitsu Tsuneyoshi, Institute for Biotechnology Research, Wakunaga Pharmaceutical Co., Ltd., 1624 Shimokotachi, Koda-Cho, Takata-Gun, Hiroshima 739-11, Japan; Shin-ichiro Sumi, Institute for Biotechnology Research, Wakunaga Pharmaceutical Co., Ltd., 1624 Shimokotachi, Koda-Cho, Takata-Gun, Hiroshima 739-11, Japan. Phytopathology 86:253-259. Accepted for publication 6 November 1995. Copyright 1996 The American Phytopathological Society. DOI: 10.1094/Phyto-86-253.

A total of six viruses belonging to at least three distinct genera, Potyvirus, Carlavirus, and a novel unclassified genus, were identified from infected garlic plants in Japan based on partial cDNA cloning and sequencing of genomes. We developed procedures that combined reverse-transcription polymerase chain reaction (RT-PCR) with restriction analysis for identification of each of the six viruses. The respective viral coat protein genes were expressed as fusion proteins in Escherichia coli, and the products were used as immunogens for producing antibodies that reacted against viral particles. The antisera obtained specifically recognized each of three types of rod-shaped virus particles according to immunoelectron microscopy and enzyme-linked immunosorbent assay. Furthermore, a convenient serological method based on direct tissue blotting immunoassay (DTBIA) was developed. Survey of virus incidence using both DTBIA and RT-PCR presented direct evidence for mixed infections of garlic plants with several viruses. In addition, DTBIA is suitable for large-scale and routine diagnosis of garlic viruses.