Multicellular living organisms and unmodified parts thereof and – Method of introducing a polynucleotide molecule into or... – The polynucleotide alters carbohydrate production in the plant
Reexamination Certificate
2001-10-19
2004-05-11
Fox, David T. (Department: 1638)
Multicellular living organisms and unmodified parts thereof and
Method of introducing a polynucleotide molecule into or...
The polynucleotide alters carbohydrate production in the plant
C800S278000, C800S287000, C800S320000, C800S320100, C800S320200, C800S320300, C435S069100, C435S101000, C435S194000, C435S412000, C435S419000, C435S424000
Reexamination Certificate
active
06734340
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to monocotyledon plant cells and plants which are genetically modified, wherein the genetic modification consists of the introduction of an extraneous nucleic acid molecule which codes for a protein with the biological activity of an R1 protein. The present invention further relates to means and methods for the production thereof. Plant cells and plants of this type synthesise a modified starch which is characterised in that it has an increased phosphate content and/or a modified phoshorylation pattern and/or an increased final viscosity in an RVA profile and/or a reduced peak temperature in DSC analysis and/or an increased gel strength in the texture analysis compared with starch from corresponding non-genetically modified monocotyledon plants. Therefore, the present invention also relates to the starch which is synthesised from the plant cells and plants according to the invention, and to methods of producing said starch. The present invention further relates to wheat flours which contain said modified starches, and to food products and bakery products which contain said wheat flours and/or starch.
With regard to the increasing importance which has recently been attached to substances of plant content as renewable sources of raw materials, one of the tasks of biotechnological research is to endeavour to adapt these plant raw materials to the requirements of the industry which processes them. To facilitate the use of renewable raw materials in as many fields of use as possible, it is also necessary to provide a considerable multiplicity of substances.
Apart from oils, fats and proteins, polysaccharides constitute the important renewable raw materials from plants. In addition to cellulose, starch, which is one of the most important storage materials in higher plants, assumes a central position in polysaccharides.
Polysaccharide starch is a polymer of chemically uniform basic components, namely glucose molecules. However, it is a very complex mixture of different forms of molecules, which differ with regard to their degree of polymerisation and the occurrence of branched region in the glucose chains. Starch therefore does not constitute a uniform raw material. A distinction is made between two chemically different components of starch: amylose and amylopectin. In typical plants which are used for starch production, such as maize, wheat or potatoes, the synthesised starch consists of up to about 20%-30% of amylose starch and up to about 70%-80% of amylopectin starch.
Amylose was for a long time considered to be a linear polymer consisting of &agr;-1,4-glycosidically bonded &agr;-D-glucose monomers. In more recent studies, however, the presence of about 0.1% of &agr;-1,6-glycosidic branching sites has been detected (Hizukuri and Takagi, Carbohydr. Res. 134, (1984), 1-10; Takeda et al., Carbohydr. Res. 132, (1984), 83-92). Basically, however, achieving a complete separation of amylose from amylopectin very difficult, so that the quality of the amylose is strongly dependent on the type of separation method selected. In contrast to amylose, amylopectin is more strongly branched and comprises about 4% of branching sites which are formed due to the occurrence of additional &agr;-1,6-glycoside linkages. Amylopectin constitutes a complexes mixture of differently branched glucose chains. A further significant difference between these two molecules is their molecular weight. Whereas amylose, depending on the origin of the starch, has a molecular weight of 5×10
5
-10
6
Da, that of amylopectin ranges between 10
7
and 10
8
Da. These two macromolecules can be by distinguished by their molecular weight and by their different physicochemical properties, which are most readily manifested by their different iodine bonding properties.
A further significant difference between amylose and amylopectin is the relative amounts of trace substances which can exist in association with these macromolecules. Amylose has a high affinity for hydrophobic molecules. In cereals in particular, amylose can be complexed with relatively high amounts of lipids (Morrison, Cereal Foods World 40, (1995), 437-446). On the other hand, amylopectin can contain covalently bonded inorganic phosphate in the form of starch phosphate monoesters, which has not hitherto been described for amylose. High contents of phosphate monoesters are found in particular in starches which are obtained from tubers. Amongst commercially available starches, potato starch has the highest phosphate content, which can range between 10-30 nmol mg
−1
starch. In some types of Curcuma the phosphate content can even be 2 to 4 times higher (Bay-Smidt et al., 5th ISPMP Meeting Proceedings, (1997), 741), whilst it is about 100 times less in cereals (Kasemsuwan and Jane, Cereal Chem. 73, (1996), 702-707). In contrast to starches from tubers, roots and legumes, the detectable phosphate in cereal starches (monocotyledon plants) rarely occurs in the form of starch monoester derivatives, but mainly occurs in the form of phospholipids (Jane et al., Cereal Foods World 41, (1996), 827-832).
Apart from its amylose/amylopectin ratio and phosphate content, the functional properties of starch are influenced by its molecular weight, its pattern of side chain distribution, its content of ions, its lipid and protein content, etc. Important functional properties which should be cited here are the solubility, the retrogradation behaviour, the water absorption capacity, the film-forming properties, the viscosity, the conglutination properties, the freeze-thaw stability, the stability in relation to acids, the gel strength, etc. The starch grain size can also be important for various applications.
In principle, the phosphate content can be modified either by genetic engineering approaches or by the subsequent chemical phoshorylation of native starches (see, for example: Starch Chemistry and Technology. Eds. R. L. Whistler, J. N. BeMiller and E. F. Paschall. Academic Press, New York, 1988, 349-364). Chemical modifications are generally costly and time-consuming, however, and result in starches, the physicochemical properties of which can differ from those of starches modified in vivo.
Since starches from monocotyledon wild-type plants, particularly from cereal plants (wheat, rice, maize, oats, millet, rye), only have a very low content of phosphate in the form of starch phosphate monoesters (Lim et al. Cereal Chem. 71, (1994), 488), one object of the present invention is to provide monocotyledon plants which synthesise starches with an increased phosphate content (content of starch phosphate monoesters) and modified physicochemical properties compared with corresponding wild-type plant cells and plants.
The underlying object of the present invention is thus to provide genetically modified monocotyledon plant cells and plants which synthesise starches with modified structural and/or functional properties compared with corresponding non-genetically modified wild-type plant cells and plants, and is also to provide starch, the structural and/or functional properties of which differ from those of starch from corresponding non-genetically modified wild-type plant cells and plants and from those of chemically modified starch, and which is thus more suitable for general and/or special industrial purposes of use.
This object is achieved by the provision of the embodiments described in the claims, because it has surprisingly been found that the introduction of an extraneous nucleic acid molecule into the genome of monocotyledon plant cells and plants results in a modification of the structural and/or functional properties of the starch which is synthesised in said monocotyledon plant cells and plants.
Expression of the extraneous nucleic acid molecule is primarily advantageous in starch-storing organs of monocotyledon plants, particularly of wheat plants, and leads to an increase of the phosphate content and modification of the viscosity properties of the starch which can be isolated from the starch-storing organs com
Amati Simeone Franceska
Becker Drik
Knies Petra
Landschutze Volker
Lorz Horst
Bayer CropScience GmbH
Fox David T.
Frommer & Lawrence & Haug LLP
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