Virus-like particles associated with the mycoplasmas of clover phyllody in the plant and in the insect vector.

Abstract

SUMMARY: In a few phloem cells in root nodules of clover (Trifolium repens L.) and salivary glands of Euscelis lineolatus Brullé, which were naturally or experimentally infected by the mycoplasmas of clover phyllody, rod-shaped virus-like particles were found which had at least one rounded end. These particles had a diameter of 27 ± 3 nm, a dense core of diameter 16 ± 2nm and a clear axis. Their mean length was between 50 and 90 nm. Even when they were free in the phloem sap of the plant or in the haemolymph of the insect they were in the vicinity of some mycoplasmas. Sometimes they were crowded in a monolayer inside the cytoplasm of the plant cell. They were also found in the form of a rosette around some mycoplasmas which seemed degenerated. The occurrence, size, shape, internal structure and position of these virus-like particles is illustrated; their nature and pathogenicity in comparison with Mycoplasmatales Virus laidlawii 1 and the virus-like particles sometimes associated with plant pathogenic mycoplasmas is discussed.