In my construct, I have LacI operator upstream of target genes and lacI protein is expressed constitutively. I can successfully produce gene, if I pick yeast colony from YNB plate (with appropriate amino acids) containing 2% glucose, then grow it overnight on same liquid YNB media bcontaining 2% galactose+IPTG (induction medium for gene expression). Now, I need to express interested gene on the plate. I added galactose and IPTG to the plate, unfortunately I cannot get any colony . Could be helpful, adding 1% raffinose in addition to the 2% galactose and IPTG?