Development of PCR-Based Molecular Marker for Detection of Xanthomonas campestris pv. campestris Race 6, the Causative Agent of Black Rot of Brassicas

• Main Authors: Khandker Shazia Afrin, Md Abdur Rahim, Mehede Hassan Rubel, Jong-In Park, Hee-Jeong Jung, Hoy-Taek Kim, Ill-Sup Nou
• Format: Article
• Language: English
• Published: Hanrimwon Publishing Company 2020-10-01
• Series: The Plant Pathology Journal
• Subjects: black rot; cabbage; molecular marker; race 6; xanthomonas campestris pv. campestris
• Online Access: http://www.ppjonline.org/journal/view.html?doi=10.5423/PPJ.OA.06.2020.0103

Xanthomonas campestris pv. campestris (Xcc), the pathogen of black rot which is the most destructive disease of Brassica vegetables throughout the world. Here, we reported two novel sequence-characterized amplified region (SCAR) markers (i.e., XccR6-60 and XccR6-67) for the detection of Xcc race 6 via re-alignment of the complete genome sequences of Xcc races/ strains/pathovars. The specificity of SCAR primer sets was verified by mean of PCR amplification using the genomic DNA template of Xcc races/strains/pathovars and two other plant infecting bacterial strains. The PCR result revealed that the XccR6-60 and XccR6-67 primer sets amplified 692-bp and 917-bp DNA fragments, respectively, specifically from race 6, while no visible amplification was detected in other samples. In addition, the SCAR primers were highly sensitive and can detect from a very low concentration of genomic DNA of Xcc race 6. However, the complete genome sequence of Xcc race 6 is not yet publicly available. Therefore, the cloning and sequencing of XccR6-60 and XccR6-67 fragments from race 6 provide more evidence of the specificity of these markers. These results indicated that the newly developed SCAR markers can successfully, effectively and rapidly detect Xcc race 6 from other Xcc races/strains/pathovars as well as other plant pathogenic bacteria. This is the first report for race-specific molecular markers for Xcc race 6.