CHARACTERIZATION OF A HIGHLY REPEATED DNA-SEQUENCE (SC1) FROM THE ARBUSCULAR MYCORRHIZAL FUNGUS SCUTELLOSPORA-CASTANEA AND ITS DETECTION INPLANTA

A highly repeated DNA sequence from the genome of an arbuscular mycorr hiza! fungus has beep isolated and characterized. This 1,202-bp sequen ce (SC1) represents about 0.24% of the Scutellospora castanea genome, estimated to be 1 pg by flow cytometry. The sequence was shown to be a Scutellospora-specific probe in Southern blots and dot blot hybridiza tions, After complete sequencing of SC1, PCR primers were generated an d used to amplify a 907-bp fragment from spores of S, castanea or from colonized Allium porrum roots. No amplification products were obtaine d with DNA from either spores or mycorrhizal root of other species of arbuscular mycorrhizal fungi, These primers were sufficiently specific for unequivocal detection of S. castanea in planta.