Multicellular living organisms and unmodified parts thereof and – Plant – seedling – plant seed – or plant part – per se – Higher plant – seedling – plant seed – or plant part
Patent
1997-07-28
2000-01-04
McElwain, Elizabeth F.
Multicellular living organisms and unmodified parts thereof and
Plant, seedling, plant seed, or plant part, per se
Higher plant, seedling, plant seed, or plant part
4353201, 536 236, A01H 500, C12N 1582
Patent
active
060112018
DESCRIPTION:
BRIEF SUMMARY
This invention relates to the .beta.-ketoacyl ACP reductase genes from Brassica napus and uses thereof.
The overall pathway of fatty acid synthesis from malonyl CoA is the same in all organisms. However the structural organisation of the participating enzymes varies widely among different kingdoms. A single multifunctional fatty acid synthase (FAS) polypeptide is found in mammals, whereas two interacting multifunctional polypeptides function in yeast. In contrast, in prokaryotes and plants each step in the FAS pathway is catalysed by a separate monofunctional enzyme. The enzyme activities which make up this pathway include "condensing enzymes" which catalyse the reaction of malonyl ACP with an acyl ACP (or acetyl CoA in the case of KASIII which initiates the pathway) producing a .beta.-ketoacyl ACP (with a chain length 2 carbon atoms longer than the initial acceptor). These molecules are then reduced by .beta.-ketoacyl ACP reductase to a .beta.-hydroxyacyl ACP. A dehydratase enzyme then converts this intermediate to an enoyl ACP which is subsequently reduced by enoyl reductase to generate a fatty acyl ACP. In plants evidence from cellular fractionation and immunolocalisation studies suggests that fatty acid synthesis takes place in plastids. In leaves these are chloroplasts, in seeds these are leucoplasts.
This invention is principally concerned with genes encoding the FAS pathway enzyme NADPH linked .beta.-ketoacyl ACP reductase (.beta.-ketoreductase). Two forms of this enzyme, one NADPH-linked, the other NADH-linked, have been reported to be localised in plastids. The function of the NADH-linked enzyme is unknown. It is the NADPH-linked enzyme that functions in fatty acid biosynthesis. This NADPH-linked .beta.-ketoreductase is coordinately induced with other fatty acid biosynthetic enzymes, just before and during lipid accumulation in developing oil seeds.
Partial length cDNA clones encoding .beta.-ketoreductase, of chain length 0.32 kb and 0.1 kb have already been isolated from a cDNA library from developing seed of Brassica napus, and a full length cDNA within a 1.2 kb clone has already been isolated from a cDNA library from Arabidopsis leaf (Slabas et al (1992)).
An object of this invention is to provide gene sequences encoding .beta.-ketoacyl ACP reductase.
According to the present invention there are provided: pJGR27.11.
The cDNA of rape seed .beta.-ketoreductase, according to the invention, may be used as a heterologous probe to select clones of .beta.-ketoreductase genes from other oilseeds eg soya, sunflower, maize, coconut, oil palm.
Also, the genomic DNA of rape seed .beta.-ketoreductase may be used to recover the promoter of this gene. This promoter can be used to generate RNA in a tissue specific and developmentally regulated way. The RNA so generated may promote expression of .beta.-ketoreductase or may encode another protein, for example another enzyme, which will then be expressed specifically in the developing oilseed.
Additionally, the cDNAs of rape seed ketoreductase can be used to make expression cassettes (sense or antisense) to transform rape to down regulate production of the seed .beta.-ketoreductase enzyme. This will produce rape plants with low or modified oil content. Down-regulation will divert metabolism of assimilates into alternative storage compounds eg starch, protein or other polymers inserted by genetic engineering, such as PHB.
Further according to the invention full length cDNAs of rape .beta.-ketoreductase can be used to create expression cassettes either with a powerful promoter, or by inserting extra copies of the gene, to promote over-expression of .beta.-ketoreductase, leading to rape plants with enhanced oil content.
The full length cDNAs of rape seed and leaf ketoreductase genes contain "transit peptide" sequences which direct the ketoreductase proteins to chloroplasts or leucoplasts, the transit peptide being cleaved of during import of the protein into the plastid. These transit peptides can therefore be used in gene fusions to direct other proteins to the pla
REFERENCES:
patent: 5110728 (1992-05-01), Kridl et al.
Napoli et al. Introduction of a chimeric chalcone synthase gene into petunia results in reversible co-suppression of homologous genes in trans. The Plant Cell. 2:279-280, Apr. 1990.
Smith et al. Antisense RNA inhibition of polygalacturonase gene expression in transgenic tomatoes. Nature. 334:724-726, Aug. 1988.
Slabas et al. The biochemistry and molecular biology of plant lipid biosynthesis. Plant Molecular Biology. 19:169-191, May 1992.
Thomas, Neil C., et al., (1995) Plant Lipid Metab., meeting date, Jun. 26-Jul. 1, 1994 11:99-101.
Martinez-Rivas, J.M., et al. (1993) Grasas Y Aceites 44;119-120.
Sheldon, P.S., et al. (1992) Biochim Biophys Acta 1120:151-159.
Klein, B., et al. (1992) Molecular and General Genetics 233:122-128.
Kapff, M., et al. (1993) Biol. Chem. Hoppe-Seyler, 374:528.
Chase Dianne
Elborough Keiran
Fentem Philip Anthony
Slabas Antoni Ryszard
White Andrew
Bond Gary M.
McElwain Elizabeth F.
Zeneca Limited
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