Ultrastructure of mixed plant virus infection: bean yellow mosaic virus with cowpea severe mosaic virus or cowpea mosaic virus in bean.
Ultrastructural responses of bean leaf cells simultaneously infected with two morphologically distinct RNA viruses, cowpea mosaic virus (CPMV) and bean yellow mosaic virus (BYMV), or cowpea severe mosaic virus (CSMV) and BYMV, were studied in situ. The major effects on cells infected with two viruses included: (1) association of virus group-specific cytoplasmic inclusions characteristic of each virus; (2) close association of virions into specifically arranged aggregates in which CPMV or CSMV icosahedra were aligned along the long axes of the BYMV rods; and (3) the induced formation of intranuclear inclusions, spheres (22-26 nm in diameter) and filaments (10-14 nm wide and of variable length) in mixed infections of CSMV and BYMV. Intracellular serological testing using ferritin conjugated with CSMV antibodies revealed no relationship between the spherical intranuclear inclusions and CSMV capsids. We conclude that the ultrastructure of mixed infections could be used as another tool for identifying related plant viruses.
Carr
R J
RJ
Department of Plant Pathology, University of Arkansas, Fayetteville, Arkansas 72701, USA.
Kim
K S
KS