FILAMENTOUS FLEXUOUS PARTICLES AND SEROLOGICALLY RELATED PROTEINS OF VARIABLE SIZE ASSOCIATED WITH CITRUS PSOROSIS AND RINGSPOT DISEASES

Filamentous flexuous particles of unusual morphology, previously assoc iated with several ringspot isolates, were detected also in psorosis A and psorosis B isolates by serologically specific electron microscopy using an antiserum to citrus ringspot. Upon partial purification of s ix ringspot, six psorosis A, and three psorosis B isolates, a specific protein of 47 kDa was detected in most cases, but two isolates (one p sorosis A and one ringspot) had a 46 and a 48 kDa-protein, respectivel y. These differences in molecular masses were observed when purificati on was done from different host species or from plants co-inoculated w ith two isolates differing by their protein size. The three types of p rotein were serologically related in Western blots. Our results indica te that a common virus with different strains may be involved in psoro sis A, psorosis B, and ringspot diseases.