Incidence and natural hosts of Tomato leaf curl Palampur virus in Iran

Among the reported begomoviruses which cause tomato leaf curl disease (TLCD) in Iran, Tomato leaf curl Palampur virus (ToLCPMV) was the first bipartite begomovirus to be detected in tomato in 2006 in Hormozgan Province (southern Iran). Following this, the ToLCPMV incidence has progressively increased amongst several cultivated plants and to new geographical regions within Iran. We detected ToLCPMV by PCR in six crop species - tomato, cucumber, three different local cultivars of melon, squash, watermelon and bean in commercial greenhouses, plastic tunnels and/or open farms. Squash, watermelon, bean and two weed species, Chenopodium sp. and Heliotropium europaeum, represent new natural hosts of ToLPMV globally. The ToLCPMV epidemic has been particularly devastating on cucumber, melon, and squash crops. Infections rates of between 50 and 100 % were identified amongst greenhouse grown cucumbers and melons farms. However, the rate of infection in watermelon and bean were negligible. Full-length genome characterization of ten ToLCPMV isolates from cucumber, melon, squash, watermelon and bean showed a minimum 95 % sequence identity with previously characterized ToLCPMV isolates (DNA-A). The movement of ToLCPMV from south-eastern Iran to south, northeast and central regions with warm climatic conditions threatens the cultivation of cucurbits and tomato in these regions, which are the major production areas for these crops.