Gel shift assays with crude extracts of different pathovars of P. syringae. Radiolabeled P
fragment was incubated with protein extracts of P. syringae pv. phaseolicola strains NPS3121and CLY233, and P. syringae pv. tomato DC3000, grown at 18°C and 28°C in M9 minimal medium. Gel shift assays were carried out under conditions similiar to those used with crude extracts of the wild-type strain. The arrow indicates the DNA-protein complex.