PstI is not blocked by Dam, Dcm or CpG methylation. However PstI is blocked by certain types of methylation sometimes found in plant DNA. Plants often have CAG and/or CTG methylation leading to MTG and/or MAG sites. Where M is 5mC. Pst I is blocked by this type of methylation. This is not the same as CpG methylation(MG as opposed to MTG and MAG). Specific examples with references can be found on REBASE. Pst I will also not cut AGCTGCAG when methylated by AluI methylase.