PCR amplification of species-specific DNA sequences can distinguish among Phytophthora species.
We used PCR to differentiate species in the genus Phytophthora, which contains a group of devastating plant pathogenic fungi. We focused on Phytophthora parasitica, a species that can infect solanaceous plants such as tomato, and on Phytophthora citrophthora, which is primarily a citrus pathogen. Oligonucleotide primers were derived from sequences of a 1,300-bp P. parasitica-specific DNA segment and of an 800-bp P. citrophthora-specific segment. Under optimal conditions, the primers developed for P. parasitica specifically amplified a 1,000-bp sequence of DNA from isolates of P. parasitica. Primers for P. citrophthora similarly and specifically amplified a 650-bp sequence of DNA from isolates of P. citrophthora. Detectable amplification of these specific DNA sequences required picogram quantities of chromosomal DNA. Neither pair of primers amplified these sequences with DNAs from other species of Phytophthora or from the related genus Pythium. DNAs from P. parasitica and P. citrophthora growing in infected tomato stem tissue were amplified as distinctly as DNAs from axenic cultures of each fungal species. This is the first report on PCR-driven amplification with Phytophthora species-specific primers.
Ersek
T
T
Department of Plant Pathology, University of Missouri, Columbia 65211.
Schoelz
J E
JE
English
J T
JT
D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D004271:DNA, Fungal / Q000235:genetics*; D008969:Molecular Sequence Data; D010838:Phytophthora / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D010945:Plants, Edible / Q000382:microbiology; D016133:Polymerase Chain Reaction / Q000706:statistics & numerical data; D012680:Sensitivity and Specificity; D013045:Species Specificity
D017931:DNA Primers; D004271:DNA, Fungal