Spiroplasma associated with flowers of the tulip tree (Liriodendron tulipifera L.)

Abstract

Spiroplasmas were isolated and cultivated from nonsurface-sterilized petals and bracts excised from flowers of Liriodendron tulipifera L. (tulip tree) in Anne Arundel, Charles, and Prince George's Counties in Maryland, and East Lyme County, Connecticut. All isolates grew at 30 and at 37 °C. Morphology of colonies on solid agar (1%) medium containing serum differed among isolates: some isolates formed highly diffuse, barely visible colonies; others formed distinct colonies with granular centers surrounded by minute surface or submerged 'satellite' colonies. Cellular morphology and motility of organisms in broth and in agar culture were typical of the spiroplasmas pathogenic in plants and insects. In viscous media containing methylcellulose, spiroplasmas freely suspended in the medium swam, and organisms in contact with glass slide or coverslip "crawled" across the solid surface. Growth inhibition, metabolic inhibition, and organism deformation tests failed to reveal a serologic relationship between spiroplasma strain 23-6 from tulip tree flowers and spiroplasma strain AS 576 from honey bee.