POLYNUCLEOTIDES AND METHODS FOR ENHANCING SALINITY TOLERANCE IN PLANTS

• US 20100313289A1
• Filed: 07/12/2007
• Published: 12/09/2010
• Est. Priority Date: 07/12/2006
• 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), Grains Research & Development Corporation, New South Wales Department of Primary Industry
• Inventors: Platten, John Damien, Munns, Rana Ellen, James, Richard Alexander, Byrt, Caitlin, Lagudah, Evans, Spielmeyer, Wolfgang
• Granted Patent: US 8,536,429 B2
• Time in Patent Office: Days
• US Class Current: 800/266
• CPC Class Codes: A01H 5/10 Seeds
• CPC Class Codes: A01H 6/4678 Triticum sp. [wheat]
• CPC Class Codes: C07K 14/415 from plants
• CPC Class Codes: C12N 15/8273 for drought, cold, salt resistance

Abstract

The present invention relates to polypeptides, and polynucleotides encoding therefor, with cation transporter activity. In particular, the present invention relates to methods for producing, identifying, and/or breeding transgenic or non-transgenic plants, especially wheat or barley plants, with enhanced tolerance to saline and/or sodic soils, and/or reduced sodium accumulation in an aerial part of the plant. Also provided are plants produced using these methods.

Claims

1-59. -59. (canceled)

60. A wheat or barley plant which is homozygous for a Nax2 gene that confers enhanced tolerance to saline and/or sodic soils, and/or reduced sodium accumulation in an aerial part of the plant.

61. The plant of claim 60 which is durum wheat.

62. The plant of claim 61 which has a genetic background comprising less than 50% of the genetic complement of durum Line 149, 5049 or of the cultivar Tamaroi.

63. The plant of claim 60 which is hexaploid wheat.

64. The plant of claim 60, wherein the gene is on chromosome 5A or chromosome 4A.

65. The plant of claim 60, wherein the gene encodes a polypeptide which comprises a cysteine residue at a position corresponding to amino acid number 232 of SEQ ID NO:

1 and/or an aspartic acid residue at a position corresponding to amino acid number 294 of SEQ ID NO;

1.

66. The plant of claim 60 which further comprises an allele of a Nax1 gene, and/or an allele of a Kna1 gene, which confers enhanced tolerance to saline and/or sodic soils, and/or reduced sodium accumulation in an aerial part of the plant.

67. The plant of claim 66 which is characterized by a sheath:

blade ratio of Na⁺ concentration in leaf 3 of at least about 1.5 when grown for at least 10 days in a hydroponic system using a growth medium having a NaCl concentration of 50 mM.

72. The plant of claim 60, wherein the gene encodes a polypeptide that transports sodium across a cell membrane and out of the xylem of a plant to a greater extent than it transports potassium.

68-71. -71. (canceled)

73-76. -76. (canceled)

77. A method of identifying a wheat or barley plant with enhanced tolerance to saline and/or sodic soils, and/or having a phenotype of reduced sodium accumulation in an aerial part of the plant, the method comprising detecting a nucleic acid molecule of the plant, wherein the nucleic acid molecule is linked to, and/or comprises at least a part of, a Nax2 locus in the plant that comprises an allele that confers enhanced tolerance to saline and/or sodic soils, and/or that confers reduced sodium accumulation in an aerial part of the plant.

79. The method of claim 77 which comprises:

i) hybridising a second nucleic acid molecule to said nucleic acid molecule which is obtained from said plant,

ii) optionally hybridising at least one other nucleic acid molecule to said nucleic acid molecule which is obtained from said plant; and

iii) detecting a product of said hybridising step(s) or the absence of a product from said hybridising step(s).

81. The method of claim 77, wherein the nucleic acid is detected using a technique selected from the group consisting of:

restriction fragment length polymorphism analysis, amplification fragment length polymorphism analysis, microsatellite amplification and/or nucleic acid sequencing.

82. The method of claim 77 which comprises nucleic acid amplification.

83. The method of claim 82, wherein the amplification is performed using primers pairs comprising the sequences selected from:

85. A method of obtaining a wheat or barley plant, the method comprising;

i) crossing two plants of the same species of which at least one plant comprises a Nax2 locus comprising an allele which confers enhanced tolerance to saline and/or sodic soils, and/or which confers reduced sodium accumulation in an aerial part of the plant, and

ii) screening progeny plants from the cross for the presence or absence of said Nax2 locus by the method of claim 77,

wherein progeny with said allele have enhanced tolerance to saline and/or sodic soils, and/or have reduced sodium accumulation in an aerial part of the plant, when compared to progeny lacking said allele.

87. The method of claim 77, wherein the method further comprises the step of selecting a plant with the desired genotype or of analysing the plant for at least one other genetic marker.

88. The method of claim 85, wherein at least one of the wheat plants of step i) is a hexaploid wheat plant.

89. The method of claim 88, wherein the cross is between a durum wheat plant comprising said allele and a hexaploid wheat plant lacking said allele.

90. The method of claim 85, wherein one of the wheat plants is durum wheat Line 149, T. monococcum C68-01, or a progenitor or progeny plant thereof comprising said allele.

112. The method of claim 85, wherein step i) comprises crossing a first parent plant with a second parent plant, wherein the second plant comprises a Nax2 locus which comprises the allele, and wherein the method further comprises backcrossing the progeny of the cross of step i) with plants of the same genotype as the first parent plant for a sufficient number of times to produce a plant with a majority of the genotype of the first parent but comprising said allele.

78. (canceled)

80. (canceled)

84. (canceled)

86. (canceled)

91-111. -111. (canceled)