Cereals with Altered Dormancy

• US 20090291193A1
• Filed: 10/19/2006
• Published: 11/26/2009
• Est. Priority Date: 10/20/2005
• Status: Active Grant

• Current Assignee: Commonwealth Scientific & Industrial Research Organisation (Commonwealth Of Australia As Represented By Department Of Industry, Innovation, Climate Change, Science, Research And Tertiary Education)
• Original Assignee: Commonwealth Scientific & Industrial Research Organisation (Commonwealth Of Australia As Represented By Department Of Industry, Innovation, Climate Change, Science, Research And Tertiary Education)
• Inventors: Millar, Anthony Alan, Jacobsen, John Viggo, Gubler, Franz Jacques Marie
• Granted Patent: US 8,269,082 B2
• Time in Patent Office: Days
• US Class Current: 426/661
• CPC Class Codes: A01H 5/10 Seeds
• CPC Class Codes: A01H 6/4678 Triticum sp. [wheat]
• CPC Class Codes: C12N 15/8267 Seed dormancy, germination or sprouting
• CPC Class Codes: C12N 15/8293 Abscisic acid [ABA]
• CPC Class Codes: C12N 9/0071 acting on paired donors with incorporation of molecular oxygen (1.14)
• CPC Class Codes: C12N 9/0077 with a reduced iron-sulfur protein as one donor (1.14.15)

Abstract

The present invention relates to polypeptides, and polynucleotides encoding therefor, which influence seed dormancy in cereals such as wheat and barley. In particular, the present invention relates to polypeptides with ABA 8′-hydroxylase activity, and polynucleotides encoding these proteins. Also provided are cereal plants which produce seeds that have altered rates of germination, and/or levels of dormancy, when compared to seeds from wild-type plants, as well as methods of producing such plants.

Claims

1. A cereal plant comprising a genetic variation which modifies ABA 8′

-hydroxylase activity in the seed of said cereal plant, wherein said variation is an introduced mutation in a gene encoding a ABA 8′

-hydroxylase, a combination of mutations in at least two ABA 8′

-hydroxylase genes, a transgene encoding wheat or barley ABA 8′

-hydroxylase or mutant thereof, or a transgene encoding a molecule which down-regulates the level of ABA 8′

-hydroxylase activity in the seed.

48. A method of producing seed, the method comprising;

a) growing a plant of claim 1, and

b) harvesting the seed.

49. A seed of a plant of claim 1.

50. A method of producing flour, wholemeal, starch or other product obtained from seed, the method comprising;

a) obtaining seed according to claim 49, and

b) extracting the flour, wholemeal, starch or other product.

58. A method of preparing a food product, the method comprising mixing the seed of claim 49, or flour, wholemeal or starch produced from said seed, with another ingredient.

2-8. -8. (canceled)

9. An isolated polynucleotide comprising a sequence which is:

i) a sequence of nucleotides as provided in SEQ ID NO;

1,

ii) a sequence of nucleotides as provided in SEQ ID NO;

3,

iii) a sequence of nucleotides as provided in SEQ ID NO;

6,

iv) a sequence of nucleotides as provided in SEQ ID NO;

9,

v) a sequence of nucleotides as provided in SEQ ID NO;

11,

vi) a sequence of nucleotides encoding a polypeptide comprising a sequence which is;

a) an amino acid sequence as provided in SEQ ID NO;

4,

b) an amino acid sequence as provided in SEQ ID NO;

7,

c) an amino acid sequence as provided in SEQ ID NO;

10,

d) an amino acid sequence which is at least 88% identical to a),

e) an amino acid sequence which is at least 72% identical to b),

f) an amino acid sequence which is at least 89% identical to c), or a polypeptide which is a biologically active fragment thereof, wherein the polypeptide has ABA 8′

-hydroxylase activity,

vii) a sequence of nucleotides which is at least 89% identical to ii),

viii) a sequence of nucleotides which is at least 80% identical to iii),

ix) a sequence of nucleotides which is at least 89% identical to iv), or a polynucleotide which hybridises to any one of i) to viii) under stringent conditions.

23. A vector comprising or encoding the polynucleotide of claim 9.

26. A host cell comprising the polynucleotide of claim 9.

10-13. -13. (canceled)

14. An isolated polynucleotide which, when present in a cell of a cereal plant, down-regulates the level of ABA 8′

-hydroxylase activity in the cell when compared to a cell that lacks said polynucleotide.

15. The polynucleotide of claim 14 which is operably linked to a promoter capable of directing expression of the polynucleotide in a cell of a cereal plant.

16. The polynucleotide of claim 14 which down-regulates expression of at least one ABA 8′

-hydroxylase gene, or at least one ABA 8′

-hydroxylase-1 and at least one ABA 8′

-hydroxylase-2 gene.

17. The polynucleotide of claim 14, wherein the polynucleotide is selected from:

an antisense polynucleotide, a sense polynucleotide, a catalytic polynucleotide, a microRNA and a double stranded RNA.

21. The polynucleotide of claim 17 which is a double stranded RNA (dsRNA) molecule comprising an oligonucleotide which comprises at least 19 contiguous nucleotides of a polynucleotide, wherein the portion of the molecule that is double stranded is at least 19 basepairs in length and comprises said oligonucleotide.

22. The polynucleotide of claim 21 which is expressed from a single promoter, wherein the strands of the double stranded portion are linked by a single stranded portion.

64. A vector comprising or encoding the polynucleotide of claim 14.

65. A host cell comprising the polynucleotide of claim 14.

18-20. -20. (canceled)

24-25. -25. (canceled)

27. A genetically modified plant, wherein the modified plant has decreased or increased expression of a polypeptide having ABA 8′

-hydroxylase activity relative to a corresponding non-modified plant.

66. A method of producing seed, the method comprising;

a) growing a plant of claim 27, and

b) harvesting the seed.

67. A seed of a plant of claim 27.

68. A method of preparing a food product, the method comprising mixing the seed of claim 67, or flour, wholemeal or starch produced from said seed, with another ingredient.

28-34. -34. (canceled)

35. A method of altering the rate of germination and/or dormancy of a seed of a cereal plant, the method comprising genetically manipulating said plant such that the production of a polypeptide is modified when compared to a wild-type plant, wherein the polypeptide has ABA 8′

-hydroxylase activity.

36-37. -37. (canceled)

38. A method of genotyping a cereal plant, the method comprising detecting a nucleic acid of the plant or a polypeptide encoded thereby, wherein the nucleic acid molecule is linked to, and/or comprises at least part of, an ABA 8′

-hydroxylase gene.

41. A method of selecting a cereal plant from a population of cereal plants, the method comprising;

i) genotyping said population of plants using a method of claim 38, wherein said population of plants was obtained from a cross between two plants of which at least one plant comprises an allele of an ABA 8′

-hydroxylase gene which confers upon seed of said plant an altered rate of germination or dormancy and/or an altered level of ABA 8′

-hydroxylase activity, when compared to seed of the cereal plant lacking said allele, and

ii) selecting said cereal plant on the basis of the presence or absence of said allele.

39-40. -40. (canceled)

42-47. -47. (canceled)

51-57. -57. (canceled)

59-63. -63. (canceled)