Organisms resembling Mycoplasma (Class Mollicutes), first implicated by Japanese workers as the etiological agents of some “yellows” group of plant diseases (6,10), have been shown to be associated with many diseases that inflict damage to a variety of crops of economic importance (11,12). Most of these pleomorphic microbes are non-helical and are commonly referred to as mycoplasma-1ike organism(s) (MLO) because they have not yet been characterized through cultivation in a cell-free medium. Mycoplasmal etiology of about 100 plant diseases still remains to be demonstrated because Koch’s postulates cannot be satisfied. However, a few plant pathogenic mycoplasmas have been cultured in vitro, Koch’s poltulates fulfilled, and placed in a new genus Spiroplasma because they produce helical and motile filaments (7,14,15). Rapid progress has since been made on immunological, microbiological, biochemical, biophysical, and ultrastructural characterization of these mycoplasmas, especially of S. citri -- the etiological agent of citrus stubborn disease (1,3, 5,13,29,30).

R. C. Sinha

Papers

Purification and Properties of Mycoplasma-Like Organisms from Diseased Plants