Biological control of cucumber green mottle mosaic virus
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.
1. An attenuated strain of cucumber green mottle mosaic virus (CGMMV) comprising a genome, wherein the genome is a polyribonucleotide having a sequence functionally equivalent to a variant of SEQ ID NO:18, the sequence comprising at least one of the following options a), b) and c):
a) A at a position corresponding to position 4969 of SEQ ID NO:18;
b) U at a position corresponding to position 3334 of SEQ ID NO: 18; and
c) at least six nucleic acid bases selected from:
A at a position corresponding to position 315 of SEQ ID NO: 18;
G at a position corresponding to position 1498 of SEQ ID NO:18;
U at a position corresponding to position 1660 of SEQ ID NO: 18;
U at a position corresponding to position 3430 of SEQ ID NO: 18;
G at a position corresponding to position 3528 of SEQ ID NO:18;
U at a position corresponding to position 4144 of SEQ ID NO:18;
U at a position corresponding to position 4248 of SEQ ID NO:18; and
U at a position corresponding to position 6228 of SEQ ID NO:18.
2. The attenuated strain according to claim 1 wherein the sequence of the polyribonucleotide comprises one or more of A at the position corresponding to position 4969 of SEQ ID NO: 18 and U at the position corresponding to position 3334 of SEQ ID NO: 18.
3. The attenuated strain according to claim 1 wherein the sequence of the polyribonucleotide comprises:
A at the position corresponding to position 315 of SEQ ID NO: 18;
G at the position corresponding to position 1498 of SEQ ID NO: 18;
U at the position corresponding to position 1660 of SEQ ID NO:18;
U at the position corresponding to position 3430 of SEQ ID NO: 18;
G at the position corresponding to position 3528 of SEQ ID NO: 18;
U at the position corresponding to position 4144 of SEQ ID NO:18;
U at the position corresponding to position 4248 of SEQ ID NO: 18; and
U at the position corresponding to position 6228 of SEQ ID NO: 18.
4. The attenuated strain according to claim 3 , wherein the sequence of the polyribonucleotide further comprises one or more of A at the position corresponding to position 4969 of SEQ ID NO:18 and U at the position corresponding to position 3334 of SEQ ID NO:18.
5. A composition for preventing symptoms associated with infection by wild-type CGMMV in a plant or for increasing resistance of a plant to infection by wild-type CGMMV, wherein the composition comprises an attenuated strain of CGMMV according to claim 1 and an agriculturally acceptable carrier.
6. An attenuated strain of cucumber green mottle mosaic virus (CGMMV) comprising a genome, wherein the genome is a polyribonucleotide encoding a 186 kDa protein having an amino acid sequence comprising at least one of the following options a), b) and c):
a) histidine at the position corresponding to position 1637 of SEQ ID NO:64;
b) valine at the position corresponding to position 1092 of SEQ ID NO:64; and
c) at least five amino acid residues selected from:
serine at the position corresponding to position 86 of SEQ ID NO:64;
glycine at the position corresponding to position 480 of SEQ ID NO:64;
phenylalanine at the position corresponding to position 534 of SEQ ID NO:64;
valine at the position corresponding to position 1124 of SEQ ID NO:64;
aspartic acid at the position corresponding to position 1157 of SEQ ID NO:64;
leucine at the position corresponding to position 1362 of SEQ ID NO:64; and
serine at the position corresponding to position 1397 of SEQ ID NO:64.
7. The attenuated strain according to claim 6 , wherein the polyribonucleotide further encodes a coat protein having an amino acid sequence comprising valine at the position corresponding to position 156 of SEQ ID NO:65.
8. The attenuated strain according to claim 6 , wherein the amino acid sequence of the 186 kDa protein comprises at least one amino acid residue selected from histidine at the position corresponding to position 1637 of SEQ ID NO:64 and valine at the position corresponding to position 1092 of SEQ ID NO:64.
9. The attenuated strain according to claim 6 , wherein the amino acid sequence of the 186 kDa protein comprises at least five amino acid residues selected from:
serine at the position corresponding to position 86 of SEQ ID NO:64;
glycine at the position corresponding to position 480 of SEQ ID NO:64;
phenylalanine at the position corresponding to position 534 of SEQ ID NO:64;
valine at the position corresponding to position 1124 of SEQ ID NO:64;
aspartic acid at the position corresponding to position 1157 of SEQ ID NO:64;
leucine at the position corresponding to position 1362 of SEQ ID NO:64; and
serine at the position corresponding to position 1397 of SEQ ID NO:64.
10. The attenuated strain according to claim 9 , wherein the amino acid sequence of the 186 kDa protein further comprises at least one amino acid residue selected from histidine at the position corresponding to position 1637 of SEQ ID NO:64 and valine at the position corresponding to position 1092 of SEQ ID NO:64.