Properties of Two Inhibitors of Plant Virus Infection from Fruiting Bodies of Lentinus edodes and from Leaves of Yucca recurvifolia Salisb.

One of the inhibitors, named “fruiting body protein (FBP),” was purified from fruiting bodies of Lentinus edodes, and the other, named “yucca leaf protein (YLP),” from leaves of Yucca recurvifolia Salisb. The properties of these inhibitors were investigated, and the concentration of substances for a 50% inhibition ratio of TMV infection were measured. The inhibition ratios of YLP, FBP, Poly-Lys, Poly-Orn, Poly-Arg and cytochrome c were 0.6, 6.3, 14.1, 31.6, 44.7 and 100 ppm, respectively. Two inhibitors had no RNA hydrolyzing activity and no activity to TMV aggregation. FBP and YLP prevented infection of the plant by TMV when treated within 3 days before TMV inoculation, but not when treated within 1 hr for FBP or 3 hr for YLP after TMV inoculation. It seems that these two inhibitors had a preventive effect on plant virus infection, but no curative effect.