As was the case for GUS activity in transgenic onion epidermal cells, GUS mRNA
levels increased sharply after SA treatment of peanuts transformed with the P2 and P3 promoters
but increased much less in peanuts transformed with the P and P1 promoters. Again the evidence
indicates the presence of positive regulatory elements in the P2 and P3 promoters that are responsive
to SA induction, and also the presence of negative regulatory elements in P and P1 promoters.