Molecular detection of Cylindrocarpon destructans in infected Chinese ginseng roots and soil
Ginseng (<i>Panax ginseng</i> C.A. Meyer) is one of the most important medicinal plants in China, but its yields are often reduced by a variety of root pathogens. The root rot of ginseng is a destructive soil-borne disease caused by Cylindrocarpon destructans (teleomorph: Neonectria radicicola). A species-specific polymerase chain reaction (PCR) assay was developed for rapid detection of C. destructans in diseased ginseng roots and artificially inoculated soil. One pair of specific primers was designed from comparisons of nucleotide sequences of the nuclear ribosomal internal transcribed spacer (ITS) regions of 22 fungal isolates from northeast of China. Under stringent PCR conditions, primers CD-F and CD-R amplified only a 450 bp fragment from C. destructans DNA but not from other pathogens or negative control. The sensitivity of detection was 1 pg genomic DNA per 25 ìl PCR reaction volume, and C. destructans could be specifically detected with CD-F/CD-R from infected ginseng roots and soil. The approach outlined here could be further utilized as a rapid and reliable tool for the diagnosis and monitoring of the root rot of ginseng.
Key words: Panax ginseng, Cylindrocarpon destructans, internal transcribed spacer (ITS), polymerase chain reaction (PCR), molecular detection.