Reciprocal complementation of movement function of potato viruses X and A

During isolation of strains of potato viruses X (PVX) and A (PVA) from indi genously collected potato germplasm, an inseparable association between the se viruses was discovered. As a result, all the hosts of PVX, used to fi ee PVX from PVA, also showed infection of PVA along with PVX. Furthermore, Ni candra physaloides, which is a host of PVA but not PVX, also did not free P VA from PVX. These results suggested a reciprocal complementation of moveme nt function of these viruses due to which they together infected various ho sts sensitive to PVX or PVA. Relative concentration of PVX, in all the host s tested was much higher than that of PVA.