The unicellular cyanobacterium Synechocystis sp. PCC6714 can grow not only under photoautotrophic conditions, but also under chemoheterotrophic conditions if glucose is added to the medium. This makes it useful for the study of many aspects of bioenergetic mechanisms. In contrast to its closely related strain Synechocystis sp. PCC6803, which cannot grow chemoheterotrophically, Synechocystis PCC6714 is not naturally transformable. To enable gene transfer in this strain, we established a method for the introduction of self-replicating IncQ plasmids and for gene replacement using electroporation.