A Novel Strain of Tomato Leaf Curl New Delhi Virus Has Spread to the Mediterranean Basin

Abstract

Tomato leaf curl New Delhi virus (ToLCNDV) is a whitefly-transmitted bipartite begomovirus (genus <i>Begomovirus</i>, family <i>Geminiviridae</i>) that causes damage to multiple cultivated plant species mainly belonging to the <i>Solanaceae</i> and <i>Cucurbitaceae</i> families. ToLCNDV was limited to Asian countries until 2012, when it was first reported in Spain, causing severe epidemics in cucurbit crops. Here, we show that a genetically-uniform ToLCNDV population is present in Spain, compatible with a recent introduction. Analyses of ToLCNDV isolates reported from other parts of the world indicated that this virus has a highly heterogeneous population genetically with no evident geographical, plant host or year-based phylogenetic groups observed. Isolates emerging in Spain belong to a strain that seems to have evolved by recombination. Isolates of this strain seem adapted to infecting cucurbits, but poorly infect tomatoes.