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Appl Environ Microbiol. Oct 1990; 56(10): 2994–2998.
PMCID: PMC184889

Extracellular proteases from Xanthomonas campestris pv. campestris, the black rot pathogen.


Two proteases (PRT1 and PRT2) were fractionated from culture supernatants of wild-type Xanthomonas campestris pv. campestris by cation-exchange chromatography on SP-5PW. Inhibitor experiments showed that PRT 1 was a serine protease which required calcium ions for activity or stability or both and that PRT 2 was a zinc-requiring metalloprotease. PRT 1 and PRT 2 showed different patterns of degradation of beta-casein. The two proteases comprised almost all of the extracellular proteolytic activity of the wild type. A protease-deficient mutant which lacked both PRT 1 and PRT 2 showed considerable loss of virulence in pathogenicity tests when bacteria were introduced into mature turnip leaves through cut vein endings. This suggests that PRT 1 and PRT 2 have a role in black rot pathogenesis.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.
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