On the other hand, both SA and PR1 mRNA did not accumulate to significant levels in sid2 and ald1sid2 mutants after infection (Figures 4A, B), which is consistent with ICS1/SID2 being directly involved in SA biosynthesis (Wildermuth et al., 2001; Garcion et al., 2008). This evidence concerns the gene DNAI1 and infection.