2 GROUPS OF PHYTOPLASMAS FROM JAPAN DISTINGUISHED ON THE BASIS OF AMPLIFICATION AND RESTRICTION ANALYSIS OF 16S RDNA

Phytoplasmas (mycoplasmalike organisms, MLOs) associated with mitsuba (Japanese honewort) witches'-broom (JHW), garland chrysanthemum witche s'-broom (GCW), eggplant dwarf (ED), tomato yellows (TY), marguerite y ellows (MY), gentian witches'-broom (GW), and tsuwabuki witches'-broom (TW) in Japan were investigated by polymerase chain reaction (PCR) am plification of DNA and restriction enzyme analysis of PCR products. Th e phytoplasmas could be separated into two groups, one containing stra ins JHW, GCW, ED, TY, and MY, and the other containing strains GW and TW, corresponding to two groups previously recognized on the basis of transmission by Macrosteles striifrons and Scleroracus flavopictus, re spectively. The strains transmitted by M. striifrons were classified i n 16S rRNA gene group 16SrI, which contains aster yellows and related phytoplasma strains. Strains GW and TW were classified in group 16SrII I, which contains phytoplasmas associated with peach X-disease, clover yellow edge, and related phytoplasmas. Digestion of amplified 16S rDN A with HpaII indicated that strains GW and TW were affiliated with sub group 16SrIII-B, which contains clover yellow edge phytoplasma. All se ven strains were distinguished from other phytoplasmas, including thos e associated with clover proliferation, ash yellows, elm yellows, and beet leafhopper-transmitted virescence in North America, and Malaysian periwinkle yellows and sweet potato witches'-broom in Asia.