mycoplasma Definition

any of a genus (Mycoplasma of the family Mycoplasmataceae) of pleomorphic gram-negative chiefly nonmotile bacteria that lack a cell wall and are mostly parasitic usually in mammals —called also pleuropneumonia-like organism

phytoplasma

any of a group of bacteria that are related to mycoplasmas, cause plant diseases (such as aster yellows or elm yellows) by infecting phloem tissue, and are transmitted especially by homopteran insect vectors —called also mycoplasma-like organism