MYROBALAN LATENT RINGSPOT, A BIPARTITE GENOME VIRUS AND A STRAIN OF TOMATO BLACK RING VIRUS

Myrobalan latent ringspot virus was observed in 1970. In the last years its properties have been investigated. On the basis of the sedimentation constants, the virus shows three components; one consists in the empty capsid (Top), the two others (Middle and Bottom) are nucleoprotein components. Middle component contains two RNA species, RNA₂ with estimated molecular weight of 1.9x10⁶ and RNA₃ (0.45x10⁶). Bottom component contains three RNA species, RNA₃, RNA₂ and RNA₁ (2.6x10⁶). RNA₃ appears as a minor RNA. RNAI infectivity is low and greatly enhanced by addition of RNA₂. Coat protein consists in a single subunit with a Mol wt of 53,000.

These properties suggest that MLRV could be a member of the NEPO virus group and a distant serological relationship was pointed out to some strains of tomato black ring virus.