Genetic complementation between natural strains of red clover mottle virus

Three strains of red clover mottle virus were purified and their components separated by density gradient and isopycnic centrifugation. The infectivity of the purified components and of homologous and heterologous mixtures of them was assayed using Phaseolus vulgaris. Infectivity enhancement occurred in all combinations of middle and bottom components. Local lesion isolates from heterologous combinations were propagated and their symptoms on Pisum sativum and Chenopodium quinoa are described. It was concluded that symptoms on both host species are determined by the middle component. Top component formation appeared to be influenced by both bottom and middle components.