PCR-based detection of Colletotrichum acutatum on strawberry

An oligonucleotide primer (CaInt 2) was synthesized from the variable internal transcribed spacer (ITS) region of ribosomal DNA (rDNA) from Colletotrichum acutatum. PCR with primers CaInt2 and ITS4 (from a conserved sequence of the rDNA) amplified a 490 bp fragment from several isolates of C. acutatum but not from other members of the genus Colletotrichum. Amplification of this fragment was achieved from 100 fg of fungal DNA. These primers amplified a fragment of the same size from DNA extracted from strawberry tissues infected by C. acutatum. Southern hybridization analysis confirmed the 490 bp fragment from C. acutatum DNA and infected strawberry to be identical. The species-specific primer (CaInt2) developed in this work could be used for the accurate identification of C. acutatum and its detection on other host plants.