SELECTIVE AMPLIFICATION OF RDNA INTERNAL TRANSCRIBED SPACER REGIONS TO DETECT OPHIOSPHAERELLA-KORRAE AND O-HERPOTRICHA

The internal transcribed spacer (ITS) regions of the rDNA of Ophiosphaerella herpotricha and O. korrae (= Leptosphaeria korrae) were amplified with the universal primers ITS4 and ITS5. Amplifications of genomic DNA from O. herpotricha isolates always resulted in a single 590-bp fragment, whereas amplifications of O. korrae isolates resulted in a single fragment of either 590 or 1,019 bp. Primers specific for O. herpotricha (OHITS1 and OHITS2) and O. korrae (OKITS1 and OKITS2) were derived from sequence analyses of the ITS regions. The OHITS primers amplified a 454-bp fragment from DNA of O. herpotricha but not from DNA of O. korrae or 29 other fungal or bacterial species. Similarly, the OKITS primers amplified a 454-bp fragment from DNA of O. korrae isolates only. The OHITS and OKITS primers also detected O. herpotricha or O. korrae, respectively, in total DNA preparations from greenhouse-inoculated or naturally infected bermudagrass roots. These primers can be used to rapidly diagnose turfgrass patch diseases caused by O. herpotricha and O. korrae without culturing the fungi from diseased tissue.