ISHS Acta Horticulturae 695: I International Symposium on Tomato Diseases
IDENTIFICATION OF RAPD MARKERS LINKED TO LYCOPERSICON CHILENSE DERIVED BEGOMOVIRUS RESISTANT GENES ON CHROMOSOME 6 OF TOMATO |
| Authors: | Y. Ji, J.W. Scott |
| Keywords: | Lycopersicon esculentum, RAPD marker, disease resistance, tomato yellow leaf curl virus, tomato mottle virus |
| Abstract:
Tomato yellow leaf curl virus (TYLCV) and tomato mottle virus (ToMoV) are two of the most destructive whitefly-transmitted begomoviruses of tomato (Lycopersicon esculentum). Resistance to these viruses has been found in several accessions of the wild species L. chilense. Three different regions in chromosome 6 of L. chilense have been shown to be associated with the resistance, indicating that at least three genetic loci contribute to the resistance. In the present study, we aim to identify molecular markers tightly linked to the resistant loci, by using L. chilense (accessions LA2779, LA1932, and LA1938) derived breeding lines that have been phenotypically selected for TYLCV and ToMoV resistance. Three plants from each line displaying resistance to both viruses were selected to screen against previously mapped RAPD (randomly amplified polymorphic DNA) markers. We also employed L. chilense derived F3 and segregating lines in our study. Markers displaying high reproducibility of the polymorphism between the susceptible control ‘Horizon’ and the L. chilense derived lines were identified. These include UBC697 and UBC621 from region 1 (Ty-1 gene in this region); UBC264, UBC169, UBC197, and UBC365 from region 2; and UBC131, UBC137, UBC236, and UBC389 from region 3. Among these markers, UBC697 from region 1 and UBC264 from region 2 showed tight linkage to the resistant genes, while markers from region 3 showed varied degrees of segregation from the resistant gene. We have cloned the polymorphic bands from all these markers. The conversion of these linked RAPD markers to co-dominant sequence characterized amplified region (SCAR) markers is in progress. | |
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