RFLP (restriction fragment length polymorphism) analysis of PCR-amplified 16S rDNA sequences with restriction enzymes concluded that phytoplasma causing Illinois elm yellows is a new member of clover proliferation phytoplasma group, but not elm yellows phytoplasma strains which is attributable to elm yellows disease occurring elsewhere in the U.S.

PCR/RFLP assays and a comprehensive classification scheme were developed by us at MPPL and have been adopted worldwide as the standard procedure to identify unknown phytoplasmas associated with numerous emerging phytoplasmal diseases.