DOWNY MILDEW RESISTANT LETTUCE PLANTS

• US 20170064918A1
• Filed: 08/31/2016
• Published: 03/09/2017
• Est. Priority Date: 09/03/2015
• Status: Active Grant

• Current Assignee: Seminis Vegetable Seeds Incorporated (Bayer AG)
• Original Assignee: Seminis Vegetable Seeds Incorporated (Bayer AG)
• Inventors: Brugmans, Bart Willem, Koorevaar, Gerard N., van der Laan, Hieronymus J.M., Weber, Rosa I.
• Granted Patent: US 10,448,595 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A01H 1/045 using molecular markers
• CPC Class Codes: A01H 5/12 Leaves
• CPC Class Codes: A01H 6/1472 Lactuca sativa [lettuce]
• CPC Class Codes: C12N 15/82 for plant cells , e.g. plant artificial chromosomes (PACs)
• CPC Class Codes: C12Q 1/6895 for plants, fungi or algae
• CPC Class Codes: C12Q 2600/13 Plant traits
• CPC Class Codes: C12Q 2600/156 Polymorphic or mutational markers
• CPC Class Codes: C12Q 2600/158 Expression markers

Abstract

The present disclosure provides lettuce plants exhibiting resistance to downy mildew. Such plants may comprise novel introgressed genomic regions associated with disease resistance from L. virosa. In certain aspects, compositions, including novel polymorphic markers and methods for producing, breeding, identifying, and selecting plants or germplasm with a disease resistance phenotype are provided.

Claims

1. An elite lettuce plant comprising an introgression from Lactuca virosa on chromosome 7, wherein said introgression comprises a single gene conferring improved resistance to Bremia lactucae relative to a plant lacking said introgression.

4. The elite lettuce plant of claim 1, wherein said introgression from Lactuca virosa is about 250 kb or less.

5. The elite lettuce plant of claim 1, wherein the plant comprises a Lactuca virosa allele at locus NLSAT009419770 (SEQ ID NO:

6) and a Lactuca sativa allele at locus NLSAT005132975 (SEQ ID NO;

1).

6. The elite lettuce plant of claim 1, wherein the plant comprises a Lactuca virosa allele at locus NLSAT009419770 (SEQ ID NO:

6) and a Lactuca sativa allele at locus ND0229340 (SEQ ID NO;

     11).

7. The elite lettuce plant of claim 1, wherein a sample of seed comprising said introgression was deposited under ATCC Accession Number PTA-121598.

8. A plant part of the plant of claim 1.

9. The plant part of claim 8, wherein the plant part is a cell, a seed, a root, a stem, a leaf, a head, a flower, or pollen.

2. An elite lettuce plant comprising an introgression from Lactuca virosa on chromosome 7, wherein said introgression comprises a first allele conferring improved resistance to Bremia lactucae relative to a plant lacking said introgression, and wherein said introgression lacks a second allele genetically linked to said first allele and conferring stunted growth.

3. The elite lettuce plant of claim 2, wherein said introgression from Lactuca virosa is located between locus NLSAT009419770 (SEQ ID NO:

6) and locus NLSAT005132975 (SEQ ID NO;

1) in said plant.

10. A method for producing a lettuce plant with improved resistance to Bremia lactucae, comprising:

a) crossing the elite lettuce plant of claim 2 with itself or with a second lettuce plant of a different genotype to produce one or more progeny plants; and

b) selecting a progeny plant comprising said introgression.

11. The method of claim 10, wherein selecting the progeny plant comprises identifying a progeny plant that (1) comprises a Lactuca virosa allele at a locus genetically linked to said first allele and/or lacks an elite allele present at the corresponding locus in the elite lettuce plant, and (2) lacks a Lactuca virosa allele at a locus genetically linked to said second allele, and/or comprises an allele present at the corresponding locus from in the elite lettuce plant.

12. The method of claim 11, wherein selecting a progeny plant comprises detecting at least one allele at a locus selected from the group consisting of NLSAT009419770 (SEQ ID NO:

6), ND0229340 (SEQ ID NO;

     11) and NLSAT005132975 (SEQ ID NO;

1).

13. The method of claim 12, wherein (a) the allele(s) are detected by a PCR-based method using oligonucleotide primer pair(s);

and (b) the allele at locus NLSAT009419770 is detected using the primer pair comprising SEQ ID NO;

7 and SEQ ID NO;

8;

or the allele at locus ND0229340 is detected using the primer pair comprising SEQ ID NO;

12 and SEQ ID NO;

13;

or the allele at locus NLSAT005132975 is detected using the primer pair comprising SEQ ID NO;

2 and SEQ ID NO;

3.

14. The method of claim 12, wherein selecting a progeny plant comprises detecting an allele at locus NLSAT009419770 and an allele at locus ND0229340.

15. The method of claim 10, wherein the progeny plant is an F2-F6 progeny plant.

16. The method of claim 10, wherein producing the progeny plant comprises backcrossing.

17. The method of claim 16, wherein backcrossing comprises from 2-7 generations of backcrosses.

18. The method of claim 10, wherein a sample of seed comprising said introgression was deposited under ATCC Accession Number PTA-121598.

19. A method for obtaining an elite lettuce plant exhibiting improved resistance to Bremia lactucae, comprising:

a) obtaining an elite lettuce plant heterozygous for a first allele from Lactuca virosa that confers quantitative resistance to Bremia lactucae and that is genetically linked in the plant to a second allele from Lactuca virosa that confers stunted growth, wherein the plant is heterozygous relative to a corresponding locus in said elite plant;

(b) obtaining progeny of the plant; and

(c) selecting at least a first progeny plant in which recombination has occurred such that the progeny comprises said first allele that confers quantitative resistance to Bremia lactucae but not said second allele.

20. The method of claim 19, wherein selecting the progeny plant comprises identifying a progeny plant that (1) comprises a Lactuca virosa allele at a locus genetically linked to said first allele and/or lacks an allele present at the corresponding locus in the elite lettuce plant, and (2) lacks a Lactuca virosa allele at a locus genetically linked to said second allele, and/or comprises an allele present at the corresponding locus from in the elite lettuce plant.

21. The method of claim 20, wherein selecting a progeny plant comprises detecting at least one allele at a locus selected from the group consisting of NLSAT009419770 (SEQ ID NO:

6), ND0229340 (SEQ ID NO;

     11) and NLSAT005132975 (SEQ ID NO;

1).

22. The method of claim 21, wherein (a) the allele(s) are detected by a PCR-based method using oligonucleotide primer pair(s);

and (b) the allele at locus NLSAT009419770 is detected using the primer pair comprising SEQ ID NO;

7 and SEQ ID NO;

8;

or the allele at locus ND0229340 is detected using the primer pair comprising SEQ ID NO;

12 and SEQ ID NO;

13;

or the allele at locus NLSAT005132975 is detected using the primer pair comprising SEQ ID NO;

2 and SEQ ID NO;

3.

23. The method of claim 21, wherein selecting a progeny plant comprises detecting an allele at locus NLSAT009419770 and an allele at locus ND0229340.

24. A plant produced by the method of claim 19.

25. A part of the plant of claim 24, selected from the group consisting of a cell, a seed, a root, a stem, a leaf, a head, a flower, and pollen.

26. A lettuce plant comprising an introgression from Lactuca virosa on chromosome 7, wherein said introgression comprises a single gene conferring improved resistance to Bremia lactucae relative to a plant lacking said introgression and wherein a sample of seed comprising said introgression was deposited under ATCC Accession Number PTA-121598.

27. The plant of claim 26, further defined as a plant of lettuce line CHCG413-0099.

28. A seed that produces the plant of claim 26.

29. A method for producing a lettuce plant with improved resistance to Bremia lactucae, comprising:

a) crossing the elite lettuce plant of claim 26 with itself or with a second lettuce plant of a different genotype to produce one or more progeny plants; and

b) selecting a progeny plant comprising an introgression from Lactuca virosa on chromosome 7, wherein said introgression comprises a first allele conferring improved resistance to Bremia lactucae relative to a plant lacking said first allele, and wherein said introgression lacks a second allele genetically linked to said first allele and conferring stunted growth.

30. The method of claim 29, wherein selecting a progeny plant comprises detecting at least one allele at a locus selected from the group consisting of NLSAT009419770 (SEQ ID NO:

6), ND0229340 (SEQ ID NO;

     11) and NLSAT005132975 (SEQ ID NO;

1).

31. The method of claim 30, wherein (a) the allele(s) are detected by a PCR-based method using oligonucleotide primer pair(s);

and (b) the allele at locus NLSAT009419770 is detected using the primer pair comprising SEQ ID NO;

7 and SEQ ID NO;

8;

or the allele at locus ND0229340 is detected using the primer pair comprising SEQ ID NO;

12 and SEQ ID NO;

13;

or the allele at locus NLSAT005132975 is detected using the primer pair comprising SEQ ID NO;

2 and SEQ ID NO;

3.

32. The method of claim 31, wherein selecting a progeny plant comprises detecting an allele at locus NLSAT009419770 and an allele at locus ND0229340.

33. A plant produced by the method of claim 29.