An attenuated strain of cucumber green mottle mosaic virus (CGMMV) is useful to protect cucumber plants from infection with the wild-type infectious CGMMV strain. The genome of the attenuated virus contains at least one mutation or group of mutations selected from c.4969G>A, c.3334C>T, and a group of at least six of the mutations c.315G>A; c.1498A>G; c.1660C>T; c.3430C>T; c.3528A>G; c.4144C>T; c.4248C>T; and c.6228C>T. These mutated genomes encode one or more mutations selected from R163711 in the 186 kDa readthrough replication protein, A1092V in the 129 kDa replication protein and/or the 186 kDa readthrough replication protein, and at least six mutations selected from G86S, E480G, S534F, A1124V, N1157D, P1362L, P1397S in the 129 kDa replication protein and/or the 186 kDa readthrough replication protein, and the A156V mutation in the coat protein.

An attenuated strain of cucumber green mottle mosaic virus (CGMMV) is useful to protect cucumber plants from infection with the wild-type infectious CGMMV strain. The genome of the attenuated virus contains at least one mutation or group of mutations selected from c.4969G>A, c.3334C>T, and a group of at least six of the mutations c.315G>A; c.1498A>G; c.1660C>T; c.3430C>T; c.3528A>G; c.4144C>T; c.4248C>T; and c.6228C>T. These mutated genomes encode one or more mutations selected from R163711 in the 186 kDa readthrough replication protein, A1092V in the 129 kDa replication protein and/or the 186 kDa readthrough replication protein, and at least six mutations selected from G86S, E480G, S534F, A1124V, N1157D, P1362L, P1397S in the 129 kDa replication protein and/or the 186 kDa readthrough replication protein, and the A156V mutation in the coat protein.

An attenuated strain of cucumber green mottle mosaic virus (CGMMV) is useful to protect cucumber plants from infection with the wild-type infectious CGMMV strain. The genome of the attenuated virus contains at least one mutation or group of mutations selected from c.4969G>A, c.3334C>T, and a group of at least six of the mutations c.315G>A; c.1498A>G; c.1660C>T; c.3430C>T; c.3528A>G; c.4144C>T; c.4248C>T; and c.6228C>T. These mutated genomes encode one or more mutations selected from R1637H in the 186 kDa readthrough replication protein, A1092V in the 129 kDa replication protein and/or the 186 kDa readthrough replication protein, and at least six mutations selected from G86S, E480G, S534F, A1124V, N1157D, P1362L, P1397S in the 129 kDa replication protein and/or the 186 kDa readthrough replication protein, and the A156V mutation in the coat protein.

An attenuated strain of cucumber green mottle mosaic virus (CGMMV) is useful to protect cucumber plants from infection with the wild-type infectious CGMMV strain. The genome of the attenuated virus contains at least one mutation or group of mutations selected from c.4969G>A, c.3334C>T, and a group of at least six of the mutations c.315G>A; c.1498A>G; c.1660C>T; c.3430C>T; c.3528A>G; c.4144C>T; c.4248C>T; and c.6228C>T. These mutated genomes encode one or more mutations selected from R1637H in the 186 kDa readthrough replication protein, A1092V in the 129 kDa replication protein and/or the 186 kDa readthrough replication protein, and at least six mutations selected from G86S, E480G, S534F, A1124V, N1157D, P1362L, P1397S in the 129 kDa replication protein and/or the 186 kDa readthrough replication protein, and the A156V mutation in the coat protein.