TITLE	A DNA probe for identification of Xanthomonas campestris pv. campestris, the causal organism of black rot of crucifers in Taiwan
AUTHOR	Hsin-Der Shih Department of Plant Pathology, National Chung Hsing University, Taichung, Taiwan, Republic of China Yuan-Chuen Lin Department of Plant Pathology, National Chung Hsing University, Taichung, Taiwan, Republic of China Hsiou-Chen Huang Graduate Institute of Agricultural Biotechnology, National Chung Hsing University, Taichung, Taiwan, Republic of China Kuo-Ching Tzeng Department of Plant Pathology, National Chung Hsing University, Taichung, Taiwan, Republic of China Shih-Tien Hsu Department of Plant Pathology, National Chung Hsing University, Taichung, Taiwan, Republic of China
FULL TEXT	[in HTML format] [in PDF format]
ABSTRACT	A DNA probe was developed for identification of strains of Xanthomonas campestris pv. campestris from Taiwan. EcoRI restriction fragments of total DNA from X. campestris pv. campestris strain Xcc70 were cloned into pBluescript II KS and transformed into Escherichia coli DH10B. The recombinant plasmid DNAs from clones randomly selected were labeled with digoxigenin and screened for their specificity for X. campestris pv. campestris. In Southern hybridization, one of the clones (pXcc70-8) hybridized to several EcoRI-digested fragments of total DNA from only strains of X. campestris pv. campestris. Digestion of the insert DNA of the clone pXcc70-8 with EcoRI yielded fragments of 2.7, 1.6 and 0.6 kb. When a subclone containing the 0.6 kb fragment was used as a probe (Xcc70-8-l), it hybridized with all 51 strains of X. campestris pv. campestris and all seven strains of X. campestris pv. armoraciae, but not with the 60 strains of other bacteria tested. This probe, however, distinguishably detected a single fragment of 0.7 kb in strains of X. campestris pv. campestris and a single fragment of 2.5 kb in strains of X. campestris pv. armoraciae when their total DNAs were digested with KpnI. The detection limits of the probe Xcc70-8-l for the amount of DNA was 25 pg and for the number of cells was about 6 ?104 CFU in dot blot assays. The colony and dot blot hybridizations with the probe were used to detect X. campestris pv. campestris in extracts of infected leaves of cabbage and seeds of several crucifers. The results indicate that the DNA probe can be used to detect X. campestris pv. campestris in plant tissues but probably not in seeds. The probe could be a useful tool for rapid identification of the pathogen in epidemiological studies in Taiwan.
KEYWORD	Crucifers (Brassica spp.); Detection; DNA probe; Identification; Xanthomonas campestris pv. campestris;
ARTICLE INFO	Botanical Bulletin of Academia Sinica, Volume 41 Number 2 April 2000, page 113-120, 8 pages
PUBLISHER	Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, Republic of China