Genome properties and relationships of Indian peanut clump virus

RNA extracted from the rod-shaped particles of Indian peanut clump virus (IPCV), strain L, consisted predominantly of two single-stranded species with mol. wt., estimated by gel electrophoresis of glyoxal-denatured samples, of 1.83 × 106 (RNA-1) and 1.35 × 106 (RNA-2). Both RNA-1 and RNA-2 were needed for lesion production in leaves of Phaseolus vulgaris cv. Topcrop. Strong nucleotide sequence homologies were detected among three strains of IPCV by nucleic acid hybridization tests. Less strong homologies were found between these Indian isolates and peanut clump virus (PCV) from West Africa. These results, together with similarities in symptomatology, particle size and mode of natural spread, indicate that the Indian isolates are best considered to be strains of PCV. However, no relationship was detected by immunosorbent electron microscopy either between the three Indian strains or between these and the West African strain. Although PCV has properties typical of the proposed furovirus group, no serological relationship was detected between any of the four strains and beet necrotic yellow vein, potato mop-top or soil-borne wheat mosaic viruses