First Report of Bean pod mottle virus in Soybean in Alabama.

Abstract

During October 2003, soybean (Glycine max (L.) Merr.) plants showing symptoms of delayed maturity of stems, or green stem, were observed in a soybean cultivar trial on Dee River Ranch in Pickens County, Alabama. Symptoms were characteristic of those caused by Bean pod mottle virus (BPMV). BPMV infections have been identified in other southern states, including Arkansas, Louisiana, and neighboring Mississippi, but had not yet been identified in Alabama (1,2,3). In this study, a cultivar trial was established as a nonreplicated strip test to evaluate the performance of nongenetically modified soybean cultivars in high-pH soils. The trial consisted of 12 maturity group V cultivars planted side by side in 24-row plots approximately 1 km long. The cultivars consisted of Anand, Asgrow 5547, Asgrow 5944, Delta King 5995, Deltapine 4748, Deltapine 5110, Deltapine 5989, Essex, Hutcheson, Pioneer 9594, Pioneer 9597, and USG5601T. During the season, a known vector of BPMV, the bean leaf beetle (Cerotoma trifurcate Forster), was identified in the plots (4). On 10 October, the majority of plants in the trial had senesced; however, it was observed that plants of 6 of the 12 cultivars were showing symptoms of green stem typical of BPMV infection. A visual assessment was taken to determine incidence of green stem for Asgrow 5547, Delta King 5995, Deltapine 5110, Deltapine 5989, Pioneer 9594, and USG5601T. Incidence between 1 and 5% was observed for Delta King 5995, Deltapine 5989, and Pioneer 9594. Incidence of less than 1% was observed for Asgrow 5547, Deltapine 5110, and USG5601T. Twenty soybean plants showing symptoms of green stem and retaining green leaves were sampled from each of the six cultivars by collecting one trifoliate leaf near the top of the plant. All samples were tested for BPMV using double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) according to the manufacturer's instructions (Agdia, Inc., Elkart, IN). BPMV was detected in 30% of Deltapine 5989, 10% of Delta King 5995, and 45% of Pioneer 9594 plants. BPMV was not detected in Asgrow 5547, Deltapine 5110, and USG5601T. Ten of the samples shown to be infected with BPMV using DAS-ELISA were mechanically transferred to soybean seedlings in the greenhouse. These plants developed systemic mottle symptoms typical of those caused by BPMV and tested positive for the virus BPMV using DAS-ELISA. To our knowledge, this is the first report of BPMV in Alabama.