Development of AFLP Derived SCAR Marker Linked to Disease Resistance to Late Blight (Phytophthora infestans) in Potato

Late blight caused by the oomycete Phytophthora infestans is the most serious fungal disease in potato cultivation worldwide. Late blight resistance is demanding the attention of potato breeders worldwide following recent migrations of aggressive metalaxyl-resistant isolates of Phytophthora infestans in potato production areas. Resistance to late blight was controlled by a few major genes (R gene) which can be easily overcame by new races of Phytophthora infestans and an unknown number of genes expressing a quantitative type of resistance which may be more durable. In this study, we used AFLP method to identify markers linked to resistance trait. Based on AFLP method, primer combination of E+AT/M+CTC was selected out of eighty primer combinations. The specific fragment was isolated and ligated into a T-vector, followed by transformation into E.coli. Plasmid DNA was extracted from transformants, and the target product was harvested. The whole sequence of 136 bp were determined using Tvector and designated on LBR-1 primer set. We employed the PCR with LBR-1 of the SCAR primer. As a result, 136 bp fragment was observed only on HR lines but not in S lines.