Improving the selection efficiency of the counter-selection marker pheS* for the genetic engineering of Bacillus amyloliquefaciens.

Bacillus subtilis pheS was genetically modified to obtain a counter-selection marker with high selection efficiency in Bacillus amyloliquefaciens. The application of the new replication-thermosensitive integrative vector pNZTM1, containing this marker, pheSBsT255S/A309G, with a two-step replacement recombination procedure provides an effective tool for the genetic engineering of industrially important Bacillus species.