This is regarding micro-organism so i think SNP genotyping would not be one of methods but PCR MP and ADSRRS would be in consideration. Which one will be more comfortable for E. coli. Thank you
Look up Brukers Bio-Typer, its an expensive set up but uses a shotgun proteomics approach for taxonomy the same principle could be applied for your question i should imagine.
Alternatively you could use RT-PCR to analyse gene regulation due to environmental conditions.
Conventional PCR techniques always just asks a simple question- is the gene present and cannot go much beyond this question besides sequencing.