National Institute of Biology, Večna pot 111, SI-1000 Ljubljana, Slovenia, Present address: Agricultural Institute of Slovenia, Hacquetova 17, SI-1000 Ljubljana, Slovenia
National Institute of Biology, Večna pot 111, SI-1000 Ljubljana, Slovenia
In July 2000, concentric necrotic rings and patterns were observed on greenhouse-grown pepper (Capsicum anuum L. ‘Blondi’). Symptoms were present only on lower leaves, not on young leaves or fruits. Typical tospovirus particles using electron microscopy were observed in leaf-dip preparations of symptomatic leaves. Impatiens necrotic spot virus (INSV) was detected in symptomatic but not in asymptomatic tissues using double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) with polyclonal antiserum (Loewe Biochemica, Sauerlach, Germany). Nicotiana benthamiana, N. rustica, and Petunia sp. were mechanically inoculated with sap of symptomatic leaves. Local and systemic symptoms were observed only on N. benthamiana. Tomato spotted wilt virus (TSWV) infections were later confirmed in some pepper and tomato plants with distinct systemic symptoms and in greenhouse-grown chrysanthemums, calla lilies, cyclamen and spatiphylum using DAS-ELISA with polyclonal antiserum. Severe systemic symptoms were observed only on some chrysanthemum cultivars, where the infection rate of TSWV was between 80 and 100%. Such TSWV-infected plants were not marketable. Symptomless infections by the same virus were also found. At one location, calla lilies were heavily infected by TSWV, but only local symptoms on leaves were observed. INSV was also confirmed using DAS-ELISA on different chrysanthemum cultivars. Mixed infections of TSWV and INSV were detected using DAS-ELISA on calla lilies with local necrotic rings and patterns on leaves and on Impatiens walerana with systemic necrosis. A limited number of weeds from the vicinity of greenhouses containing symptomatic plants were tested for the presence of TSWV using DAS-ELISA, and only Artemisia vulgaris was infected. Both viruses, TSWV from chrysanthemum and INSV from pepper, were isolated on test plants, and their identity was confirmed using DAS-ELISA. For further verification of TSWV and INSV infection, immunocapture reverse-transcription polymerase chain reaction was performed using general tospovirus primers (1). Amplification products of the expected size were detected and sequenced. Comparison of nucleic acid sequences of amplification products with viral sequence databases confirmed the identities of both viruses. To our knowledge, this is the first report of TSWV and INSV infection in ornamental and vegetable plants in Slovenia.
Reference: (1) R. J. Weekes et al. Acta Hortic. 431:159, 1996.