Rhizomania-resistant gene

1. A plant cell comprising a nucleotide sequence selected from the group consisting of:

a) a nucleotide sequence that encodes a polypeptide comprising the amino acid sequence of SEQ ID NO: 2 or SEQ ID NO: 3,

b) a nucleotide sequence comprising the sequence of SEQ ID NO: 1,

c) a nucleotide sequence that comprises at least 80% sequence identity to the sequence of SEQ ID NO: 1,

d) a nucleotide sequence that encodes a polypeptide which comprises an amino acid sequence at least 85% identical to SEQ ID NO: 2 or SEQ ID NO: 3, or a polypeptide encoded by SEQ ID NO: 1, and

e) a nucleotide sequence that encodes a polypeptide comprising at least one nucleotide-binding domain (NBS) comprising amino acid positions 168-227 of SEQ ID NO: 2 or amino acid positions 182-241 of SEQ ID NO: 3, at least one leucine-rich domain (LRR) comprising amino acid positions 591-613 of SEQ ID NO: 2 or amino acid positions 605-627 of SEQ ID NO: 3, and optionally at least one internal repetitive domain (IR) comprising amino acid positions 1013-1072 of SEQ ID NO: 2 or amino acid positions 1027-1086 of SEQ ID NO: 3;

wherein the plant cell is of a plant which is of a subspecies selected from the group consisting of Beta vulgaris ssp. vulgaris var. conditiva and Beta vulgaris ssp. vulgaris var. crassa/alba , and wherein the plant cell is a modified plant cell or wherein the nucleotide sequence is introgressed into the plant cell.

2. A plant or part thereof comprising the plant cell of claim 1 .

3. A seed of a plant of claim 2 comprising the plant cell.

4. The plant of claim 2 wherein the plant is resistant to at least one herbicide.

5. The plant of claim 4 wherein the herbicide is selected from the group consisting of glyphosate, glufosinate and ALS inhibitors.

6. An isolated cDNA of a nucleic acid molecule comprising a nucleotide sequence selected from the group consisting of:

a) a nucleotide sequence that encodes a polypeptide comprising the amino acid sequence of SEQ ID NO: 2 or SEQ ID NO: 3,

b) a nucleotide sequence that encodes a polypeptide which comprises an amino acid sequence at least 80% identical to SEQ ID NO: 2 or SEQ ID NO: 3, and

c) a nucleotide sequence that encodes a polypeptide comprising at least one nucleotide-binding domain (NBS) comprising amino acid positions 168-227 of SEQ ID NO: 2 or amino acid positions 182-241 of SEQ ID NO: 3, at least one leucine-rich domain (LRR) comprising amino acid positions 591-613 of SEQ ID NO: 2 or amino acid positions 605-627 of SEQ ID NO: 3, and optionally at least one internal repetitive domain (IR) comprising amino acid positions 1013-1072 of SEQ ID NO: 2 or amino acid positions 1027-1086 of SEQ ID NO: 3.

7. A method for modifying a nucleic acid sequence as defined in claim 1 wherein the method comprises the following steps:

a) providing the plant cell of claim 1 or a plant or part thereof comprising the cell, and

b) subjecting the cell or the plant to a tilling treatment.

8. A method for producing a resistance allele wherein the method comprises the following steps:

a) providing the cell of claim 1 , a plant or part thereof comprising the cell, or a nucleic acid sequence selected from the group consisting of:

i. a nucleotide sequence that encodes a polypeptide comprising the amino acid sequence SEQ ID NO: 2 or SEQ ID NO: 3,

ii. a nucleotide sequence comprising the sequence of SEQ ID NO: 1,

iii. a nucleotide sequence that comprises at least 80% sequence identity to the sequence of SEQ ID NO: 1,

iv. a nucleotide sequence that encodes a polypeptide which comprises an amino acid sequence at least 85% identical to SEQ ID NO: 2 or SEQ ID NO: 3 or to a polypeptide encoded by SEQ ID NO: 1, and

v. a nucleotide sequence that encodes a polypeptide comprising at least one nucleotide-binding domain (NBS) comprising amino acid positions 168-227 of SEQ ID NO: 2 or amino acid positions 182-241 of SEQ ID NO: 3, at least one leucine-rich domain (LRR) comprising amino acid positions 591-613 of SEQ ID NO: 2 or amino acid positions 605-627 of SEQ ID NO: 3, and optionally at least one internal repetitive domain (IR) comprising amino acid positions 1013-1072 of SEQ ID NO: 2 or amino acid positions 1027-1086 of SEQ ID NO: 3; and

b) subjecting the cell, the plant or the nucleic acid sequence to a tilling treatment or selective engineering.

9. A method for combatting rhizomania wherein the method comprises the following steps:

a) providing the plant of claim 2 , or a seed of the plant of claim 2 , and

b) cultivating the plant or the seed.

10. A method for breeding a plant comprising an RZ-3 locus, wherein the plant belongs to the genus Beta , and wherein the method comprises the following steps:

a) extracting genomic DNA of a cell, plant or seed of a plant of the Beta genus,

b) detecting the RZ-3 locus in the genomic DNA by using a molecular marker on a DNA sequence according to SEQ ID NO: 4 or on a DNA sequence according to SEQ ID NO: 5, and

c) introgressing the plant comprising the RZ-3 locus detected using the molecular marker with a second plant belonging to the genus Beta.

11. The plant of claim 2 , wherein the plant is a crop plant.

12. The plant cell of claim 1 , wherein the plant cell comprises the nucleotide sequence comprising at least 80% sequence identity to the sequence of SEQ ID NO: 1.

13. The plant cell of claim 1 , wherein the plant cell comprises the nucleotide sequence that encodes the polypeptide which comprises an amino acid sequence at least 85% identical to SEQ ID NO: 2 or SEQ ID NO: 3, or a polypeptide encoded by SEQ ID NO: 1.

14. The plant cell of claim 1 , wherein the plant cell is modified.

15. The plant cell of claim 1 , wherein the nucleotide sequence is introgressed into the plant cell.