Overexpression of starch synthase in plants
AssigneeBayer Intellectual Property GmbH
InventorsClaus Frohberg, Ralf-Christian Schmidt
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Abstract
The present invention relates to a process for increasing the phosphate content of starches of genetically modified plant cells in comparison with starches from corresponding wild-type plant cells by introducing a foreign nucleic acid molecule which codes for a soluble starch synthase II. The present invention furthermore relates to the overexpression of this soluble starch synthase II in the genetically modified plant cells. Furthermore, the present invention relates to rice starch and rice flour with improved quality characteristics, to rice grains comprising this rice starch, and to rice plants on which these rice grains grow.
Claims37
A process for increasing the phosphate content of starches of genetically modified rice plant cells to 150 to 380% in comparison with starches from corresponding wild-type rice plant cells (100%), comprising overexpressing a foreign nucleic acid molecule coding for a soluble starch synthase II in a genetically modified rice plant cell, wherein expression of soluble starch synthase II in said genetically modified rice plant cell is increased six to ten times compared to expression of soluble starch synthase II in a corresponding wild-type rice plant cell.
A rice starch comprising a DSC T-onset temperature of between 70° C. and 80° C. and a phosphate content at position C6 between 0.9 and 2.5 nmol phosphate per milligram of starch, wherein said rice starch is obtained from a genetically modified rice plant cell that overexpresses a foreign nucleic acid molecule coding for a soluble starch synthase II, and wherein said expression of soluble starch synthase II in said genetically modified rice plant cell is increased six to ten times compared to expression of soluble starch synthase II in a corresponding wild-type rice plant cell.
A genetically modified rice grain comprising an overexpressed foreign nucleic acid molecule coding for a soluble starch synthase II, wherein starch from said rice grain comprises:
- (a) a phosphate content at position C6 between 0.9 and 2.5 nmol phosphate per milligram of starch;
- and/or
- (b) a content of amylopectin side chains with a DP of 6-10 decreased by 20-60% in comparison with rice starch from corresponding wild-type rice plants,
- wherein expression of soluble starch synthase II in said genetically modified rice grain is increased six to ten times compared to expression of soluble starch synthase II in a corresponding wild-type rice grain.
Rice grains obtained from a genetically modified rice plant comprising an overexpressed foreign nucleic acid molecule coding for a soluble starch synthase II, wherein expression of soluble starch synthase II in said genetically modified rice plant is increased six to ten times compared to expression of soluble starch synthase II in a corresponding wild-type rice plant, and
- wherein said rice grains, when cooked, comprise:
- (a) a stickiness of −10 to −130 g measured in grams of tensile force;
- (b) an elongation rate increased by 14% to 18% compared to cooked rice grains from corresponding wild-type rice plants;
- and/or
- (c) a coefficient of dimensional changes (CDC) value of 3.5 to 5.5.
A process for increasing the phosphate content of starches of genetically modified rice plant cells to 150 to 380% in comparison with starches from corresponding wild-type rice plant cells (100%), comprising overexpressing a foreign nucleic acid molecule coding for a wheat soluble starch synthase II in a genetically modified rice plant cell.
A rice starch comprising a DSC T-onset temperature of between 70° C. and 80° C. and a phosphate content at position C6 between 0.9 and 2.5 nmol phosphate per milligram of starch, wherein said rice starch is obtained from a genetically modified rice plant cell that overexpresses a foreign nucleic acid molecule coding for a wheat soluble starch synthase II.
A genetically modified rice grain comprising an overexpressed foreign nucleic acid molecule coding for a wheat soluble starch synthase II, wherein starch from said rice grain comprises:
- (a) a phosphate content at position C6 between 0.9 and 2.5 nmol phosphate per milligram of starch;
- and/or
- (b) a content of amylopectin side chains with a DP of 6-10 decreased by 20-60% in comparison with rice starch from corresponding wild-type rice plants.
Rice grains obtained from a genetically modified rice plant comprising an overexpressed foreign nucleic acid molecule coding for a soluble starch synthase II,
- wherein said rice grains, when cooked, comprise:
- (a) a stickiness of −10 to −130 g measured in grams of tensile force;
- (b) an elongation rate increased by 14% to 18% compared to cooked rice grains from corresponding wild-type rice plants;
- and/or
- (c) a coefficient of dimensional changes (CDC) value of 3.5 to 5.5.
Dependencies are inferred from the claim text.