Submitted to: Journal of Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/8/2002
Publication Date: N/A
Interpretive Summary: An improved laboratory assay was developed for detection of the fungus that causes potato late blight disease. Development of such an assay is a high priority within the community of late blight researchers and in the potato industry. The assay, based on DNA information, provides greater specificity for the late blight pathogen than previously described assays. The new assay was also combined with a simplified detection technique based on observing color changes in the samples. The described assay will have application for detection of the late blight pathogen in infected potatoes from seedlots and storages, making detection more certain than before.
Technical Abstract: Sequences of ribosomal DNA from 10 different species of Phytophthora were analyzed and used to construct ligase chain reaction (LCR) primers for detecting the late blight pathogen, P. infestans. The LCR method allows greater specificity than previously described polymerase chain reaction (PCR) primers, and allow differentiation of P. infestans, P. mirabilis, and P. phaseoli, which contain identical ITS2 rDNA sequences, from other Phytophthora species. LCR was coupled with PCR to increase the sensitivity of detection. By labeling LCR primers with biotin and digoxigenin, the assay was combined with an ELISA-based detection system to improve sensitivity and ease of application. The new assay will provide a useful tool for detecting P. infestans in potato seedlots and storages.