Identification of natural sources of resistance to bipartite begomovirus TYLCKaV in Solanum melongena

Yellow leaf curl disease caused by begomoviruses has emerged as a major limitation to the production of eggplant ( Solanum melongena ) in several regions of the world. Tomato yellow leaf curl Kanchanaburi virus (TYLCKaV) is a bipartite begomovirus isolated from diseased eggplant in the areas of the Indochinese peninsula, South China, and Maritime Southeast Asia. In this study, five begomovirus species isolated in Indonesia, including TYLCKaV, were inoculated to eggplant using infectious clones. Among the inoculated begomoviruses, TYLCKaV alone induced typical yellowing and curling symptoms in eggplant. Inoculation of TYLCKaV to a panel of crop species (eggplant, tomato, pepper, tobacco, cucumber, melon, and squash) commonly grown in Indonesia clarified that TYLCKaV infects and causes yellow leaf curl disease mainly in eggplant and tomato. Agroinfiltration of TYLCKaV to 736 accessions of eggplant enabled selection of 33 resistant candidates. Further evaluation by TYLCKaV graft-inoculation of the resistant candidates clarified that 10 accessions were classifiable as moderately resistant and 23 accessions as highly resistant. Among the highly resistant accessions, 22 accessions restricted viral DNA accumulation to a significantly lower amount than the susceptible control. These 22 highly resistant accessions represent valuable genetic resources for breeding begomovirus resistance in eggplant.