Tomato (Solanum lycopersicum L.) is an economically important crop worldwide. In addition, tomato serves as an excellent model system for plant genetics and biology, including fruit biology, abiotic stress tolerance, and plant-microbe interactions. Development and practical use of molecular markers have been actively pursued in molecular breeding programs for tomato, especially for disease resistance to allow selection of single resistance genes and combination of multiple resistance genes. Due to insufficient genetic variation in cultivated tomatoes, various wild relatives of tomato have been investigated and utilized as disease resistance sources. In order to pursue the resistance provided by these wild relatives in developing new tomato varieties, molecular markers have been developed and intensively utilized in tomato breeding programs. Tomato yellow leaf curl virus, which is transmitted by the whitefly (Bemisia tabaci), is a major threat to tomato production worldwide. The Ty1 and Ty3 resistance loci originated from Solanum chilense LA1969 and LA1932/LA2779, respectively. Recently, the gene responsible for Ty1 resistance was identified as a DFDGD-class RNA-dependent RNA polymerase and was demonstrated to be allelic with Ty3 resistance. Ty2 resistance originated from S. habrochaites “B6013” and was recently mapped to a 300-kb interval on chromosome 11. Ty4 was identified on chromosome 3 as an additional resistance locus in Ty3-carrying S. chilense. A recessive resistance locus ty5 was identified in S. peruvianum and has been recently identified as a Pelo gene, which is the messenger RNA surveillance factor Pelota implicated in the ribosome recycling phase of protein synthesis. In this study, DNA markers for these TYLCV resistance genes are developed and summarized.
