Abstract:

The molecular taxonomy of Phytoplasmas achieved the tremendous progress due to DNA-based method was introduced from 1990s,the Phytoplasma was determined as a candidatus genus of the Mullicutes.At present,through combining DNA molecular data such as RFLP patterns,DNA sequences,nearly three hundred Phytoplasmas were classified into 14 or 20 major phylogenetic groups according to the Lee or Semmuller identification scheme,respectively.Every group or subgroup was representative of candidatus species of Phytoplasma,totally five candidatus species of Phytoplasma were published,i.e.“Candidatus Phytoplasma aurantifolia”,“Candidatus P.australiense”,“Candidatus P.australasia”,“Candidatus P.fraxini” and “Candidatus P.japonicum”.The Lee's identification scheme was listed.The problems of candidatus species concept in Phytoplasmas were discussed in detail.

Key words: Phytoplasmas, Candidatus species, Molecular taxonomy