Test for pectate lyase activity in TonB-related mutants of X. campestris pv. campestris.X. campestris pv. campestris wild-type strain B100 and mutants derived from it with disrupted genes coding for core components of the TonB system were grown for two days on M9 minimal medium supplemented with pectate and FeSO4. The positions of the inocula are indicated by dashed circles. Staining with Ruthenium Red unveiled halos encircling the inocula of the wild-type and a control strain that indicate activity of extracellular pectate lyases , while no halos were visible when the genes tonB1, exbB1, exbD1, and exbD2 were disrupted. The mutant strain B100-6.01 , carrying an ΩKm(cat) insertion in the non-coding region between tonB and exbB, was tested as a positive contro.
Vorhölter et al. BMC Microbiology 2012 12:239 doi:10.1186/1471-2180-12-239