secretes five isoenzymes of pectate lyase (PLa to PLe), which are involved in the phytopathogenicity of this bacterial species. We describe the isolation and characterization of mutants in the regulatory systems controlling PL synthesis. The regulation of PL synthesis appears to be complex, involving several controls. In one class of mutants, designated , the synthesis of various proteins became resistant to catabolite repression. This mutation mainly affected the synthesis of isoenzymes PLb and PLc. In a second class of mutants, designated , PL synthesis was no longer inducible in the presence of pectin derivatives; the regulatory gene responsible for the induction was evidently inactivated. Moreover mutations led to synthesis of PL independent of the growth phase, whereas in the wild-type strain PL synthesis increased only at the end of exponential growth. These mutations mainly affected the synthesis of PLa, PLd and PLe. Mutations in , the regulatory gene controlling 2-keto-3-deoxygluconate catabolism, had the same effects on PL synthesis as mutations.


Article metrics loading...

Loading full text...

Full text loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error