REVISED GROUP CLASSIFICATION OF THE GENUS SPIROPLASMA

Significant changes have been made in the systematics of the genus Spi roplasma (class Mollicutes) since it was expanded by revision in 1987 to include 23 groups and eight sub-groups. Since that time, two additi onal spiroplasmas have been assigned group numbers and species names. More recently, specific epithets have been assigned to nine previously designated groups and three sub-groups. Also, taxonomic descriptions and species names have been published for six previously ungrouped spi roplasmas. These six new organisms are: Spiroplasma alleghenense (stra in PLHS-1(T)) (group XXVI), Spiroplasma lineolae (strain TALS-2(T) (gr oup XXVII), Spiroplasma platyhelix (strain PALS-1(T)) (group XXVIII), Spiroplasma montanense (strain HYOS-1(T) (group XXXI). Spiroplasma hel icoides (strain TABS-2(T) (group XXXII) and Spiroplasma tabanidicola ( strain TAUS-1(T)) (group XXXIII). Also, group XVII, which became vacan t when strain DF-1(T) (Spiroplasma chrysopicola) was transferred to gr oup VIII, has been filled with strain Tab 4c. The discovery of Laborat ory, US these strains reflects continuing primary search in insect res ervoirs, Department of particularly horse flies and deer flies (Dipter a :Tabanidae). In the current revision, new group designations for 10 spiroplasma strains, including six recently named organisms, are propo sed. Three unnamed but newly grouped spiroplasmas are strain TIUS-1 (g roup XXIX; ATCC 51751) from a typhiid wasp (Hymenoptera: Tiphiidae), s train BIUS-1 (group XXX; ATCC 51750) from floral surfaces of the ticks eed sunflower (Bidens sp.) and strain BARC 1901 (group XXXIV; ATCC 700 283). Strain BARC 2649 (ATCC 700284) from Tabanus lineola has been pro posed as a new sub-group of group VIII. Strains TIUS-1 and BIUS-1 have unusual morphologies, appearing as helices at only certain stages in culture. In this revision, potentially important intergroup serologica l relationships observed between strain DW-1 (group II) from a neotrop ical Drosophila species and certain sub-group representatives of group I spiroplasmas are also reported.