RESTRICTION-FRAGMENT-LENGTH-POLYMORPHISM ANALYSES OF THE PLASMID DNASIN STRAINS OF XANTHOMONAS-CAMPESTRIS PV VESICATORIA FROM DIFFERENT GEOGRAPHIC AREAS
Bk. Hwang et al., RESTRICTION-FRAGMENT-LENGTH-POLYMORPHISM ANALYSES OF THE PLASMID DNASIN STRAINS OF XANTHOMONAS-CAMPESTRIS PV VESICATORIA FROM DIFFERENT GEOGRAPHIC AREAS, Journal of phytopathology, 143(3), 1995, pp. 185-191
Restriction fragment length polymorphisms (RFLPs) of plasmid DNAs in X
anthomonas campestris pv. vesicatoria were analysed using 77 strains f
rom the United States, Argentina, Australia, Taiwan, and Korea. One or
more plasmids were detected in all tested strains, irrespective of ge
ographic origin, host plant from which isolated, or chemical resistanc
e. All Korean strains contained a few plasmids of similar high molecul
ar weight, whereas some small plasmids occured only in strains from th
e United States, Argentina, and Taiwan. After digesting total plasmid
DNAs with each of four restriction endonucleases, 18 fragments with si
zes from about 1 to 23 kb were visualized. Seventy-seven strains of di
verse geographic origins, with different levels of resistance to strep
tomycin and copper. were classified into the 14 RFLP groups based on t
he restriction endonuclease digestion patterns of their plasmid DNAs.
Strains belonging to each group shared DNA fragments of identical size
, suggesting the possible presence of similar plasmids in these strain
s. A 5.8-kb EcoRI plasmid DNA probe prepared from the United States st
rain 81-23 hybridized to EcoRI plasmid digests from all tested strains
. Other plasmid DNA fragments of the strain 81-23 used as probes had n
o homology to plasmid DNA fragments from several strains around the wo
rld. The variation in hybridization profiles of plasmid DNA was very s
imilar to the results obtained by RFLP analysis of plasmid DNA digeste
d by four restriction enzymes. Most of the Korean strains tested were
highly sensitive to streptomycin and copper, whereas most strains from
other geographic areas showed a high level of resistance to one or tw
o of the chemicals. Cluster analysis of genetic distance between the s
trains based on the data obtained generated the dendrograms that separ
ated all Korean strains from the other strains, suggesting that plasmi
d DNA of the Korean strains may be genetically very different from tho
se of the others.