Section III, Note 6:

The instructor could have the students perform a complementation test. A complementation experiment is a test to confirm that a mutation within a particular gene is responsible for the observed phenotype. In this experiment, the wild type syrB1 gene carried on a broad host range plasmid was introduced into the newly constructed syringomycin mutant strain by electroporation. The mutant strain carrying the wild type syrB1 gene was then screened for syringomycin production. Recovery of the ability to produce syringomycin by the complemented strain confirmed that introduction of the mutated syrB1 gene in the genome of P. syringae pv. syringae was responsible for loss of the ability to produce syringomycin.