Abstract
Melon chlorotic leaf curl virus (MCLCuV) is a begomovirus that causes patchy foliar chlorosis, leaf curling, and fruit lesions in Cucumis melo cultivars, and was first reported in Guatemala in 2001. MCLCuV DNA-A and DNA-B sequences were determined from clones pMCLCV-C160D and pMCLCV-C151D, respectively. Phylogenetic analysis with well-studied begomoviruses indicated MCLCuV is distinct species, and that its closest relative is Squash yellow mild mottle virus (SYMMoV) (AY064391), at 90% shared nt identity. Therefore, SYMMoV is considered a strain of MCLCuV. Dimeric clones constructed for MCLCuV DNA-A and DNA-B components were infectious when biolistically inoculated to muskmelon plants, and symptoms were consistent with those observed under field conditions. The experimental host range for (cloned) MCLCuV was determined and included bean, cantaloupe, cucumber, Datura stramonium, Nicotiana benthamiana, pumpkin, and watermelon. Reassortment experiments with viruses of the SLCV-clade indicate that reciprocal combinations of MCLCuV with SLCV and SMLCV are viable, whereas only directional combinations of MCLCuV with CuLCV and BCaMV are viable in selected hosts. Recombination analysis for the DNA-A component indicated that MCLCuV contains a number of genome segments also present in several other Western Hemisphere begomoviruses.