Proposed subgroups of spiroplasmas of high guanine plus cytosine content, group IV.

The plant surface and insect-inhabiting spiroplasmas of group IV, unlike other spiroplasmas, have not been demonstrated to utilize arginine. They require cholesterol for growth, produce spots and films on some media, and do not hydrolize arbutin. Electrophoretic and serological comparisons of strains from North America and Europe indicate the existence of strain differences within group IV. This study provides evidence for the existence of three discrete subgroups, group IV-(1) represented by temperate American strains, group IV-(2) represented by subtropical American strain PPS1, and group IV-(3) represented by Mediterranean and French strains.