ABSTRACT
Phytoplasmas and spiroplasmas are bacteria that lack rigid cell walls. They belong to the class Mollicutes. Phytoplasmas cannot be cultured, whereas some spiroplasmas can be cultured. Both mollicutes are phloem limited in plants and can be transmitted by leafhoppers. Spiroplasmas are helical in shape. The structure of phytoplasmas and spiroplasmas, classification of phytoplasmas based on their 16S rRNA gene sequences, and diseases caused by them are described.
