Sensitive and specific detection of Clavibacter xyli subsp. xyli, causal agent of ratoon stunting disease of sugarcane, with a polymerase chain reaction-based assay.
A sensitive, specific polymerase chain reaction-based assay was developed for the detection of C. xyli subsp. xyli. This assay used oligonucleotide primers derived from the internal transcribed spacer region between the 16S and 23S rRNA genes of the bacterial rRNA operon. The assay was specific for C. xyli subsp. xyli and did not produce an amplification product from the template of the closely related bacterium C. xyli subsp. cynodontis, nor from other bacterial species. The assay was successfully applied to the detection of C. xyli subsp. xyli in fibrovascular fluid extracted from sugarcane and was sensitive to approximately 22 cells per PCR assay. A multiplex PCR test was also developed which identified and differentiated C. xyli subsp. xyli and C. xyli subsp. cynodontis in a single PCR assay.