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
1996-12-10
1999-06-08
Lau, Kawai
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
435419, 435423, 4353201, 536 232, C12N 510, C12N 1563, C07H 2104
Patent
active
059106328
DESCRIPTION:
BRIEF SUMMARY
This application claims benefit of international application PCT/GB95/00367, filed Feb. 25, 1995.
This application relates to novel DNA constructs, plant cells containing the constructs and plants derived therefrom. In particular it relates to the modification of cell wall metabolism in fruit using DNA constructs.
The modification of plant gene expression has been achieved by several methods. The molecular biologist can choose from a range of known methods to decrease or increase gene expression or to alter the spatial or temporal expression of a particular gene. For example, the expression of either specific antisense RNA or partial sense RNA has been utilised to reduce the expression of various target genes in plants (as reviewed by Bird and Ray, 1991, Biotechnology and Genetic Engineering Reviews 9:207-227). These techniques involve the incorporation into the genome of the plant of a synthetic gene designed to express either antisense or sense RNA. They have been successfully used to down-regulate the expression of a range of individual genes involved in the development and ripening of tomato fruit (Gray et al, 1992, Plant Molecular Biology, 19:69-87). Methods to increase the expression of a target gene have also been developed. For example, additional genes designed to express RNA containing the complete coding region of the target gene may be incorporated into the genome of the plant to "over-express" the gene product. Various other methods to modify gene expression are known; for example, the use of alternative regulatory sequences.
During fruit development and ripening, many biochemical changes occur that determine the composition and quality of the ripe fruit. The primary cell walls of the fruit are important constituents that influence the physical and eating properties of fresh fruit and processed products. Fruit cell walls are continually modified by both synthetic and degradative processes as the fruit expand and eventually ripen. Pectins are one of three classes of polysaccharide in the cell wall (the others being hemicelluloses and celluloses). Pectic polysaccharides in fruit consist mainly of an .alpha.1,4-galactuonan backbone with 2- and 2,4-linked rhamnosyl residues interspersed in the chain. The 2,4-linked rhamnosyl residues are thought to act as attachment points for .beta.1,4-galactosyl and .alpha.1,5-linked arabinosyl residues (Seymour et al, 1990, Phytochemistry, 29:725-731). During ripening of fruit, there is major degradation of the pectin fraction. This involves pectin solubilisation and a reduction in the molecular weight of the galacturonan backbone. In addition, there is substantial de-methylation of the C6 position of galacturonic acid residues in high molecular weight pectin. The degree of esterification has been found to fall from 90% in mature green tomato fruit, to 35% in ripe fruit (Koch and Nevins, 1990, Plant Physiology, 91:816-822).
The de-methylation (de-esterification) of pectin is catalysed by pectin esterase (hereinafter called PE). In tomato fruit, PE activity is present throughout fruit development, with activity increasing two- to three fold during ripening (Hobson, 1963, Biochemical Journal, 86:358-365). In addition, PE activity is present in other plant tissues including leaves and roots.
Two major PE isoenzymes (hereinafter called PE1 and PE2 respectively) have been identified in tomato fruit (Tucker et al, 1982, J Sci Food Agric, 33:396-400). The ratio of these isoenzymes changes during ripening, with PE2 becoming the more dominant as ripening progresses.
PE2 is the major fruit isoenzyme and several closely related cDNA clones encoding PE2 have been isolated (Ray et al, 1988, Eur J Biochem, 174:119-124; Harriman et al, 1991, Plant Physiol, 97:80-87; International patent application publication number WO93/13212). It has been reported that at least three closely related genes encode proteins of the PE2 class. The modification of PE2 gene expression has been described. For example, expression of the PE2 isoenzymes has been reduced by up to 93% in transgenic tom
REFERENCES:
Harriman, R.W. et al. "Identification and characterization of three pectin methylesterase genes in tomato" Plant Physiology (May, 1990), vol. 93, No. 1 Suppl., p. 44, Abstract 249.
Ticker et al: "Purification and changes in activities of tomato pectinesterase isoenzymes", J. Sci. Food Agric., vol. 33, 1982, pp. 396-1982.
Hall et al: "Antisense inhibition of pectin esterase gene expression in transgenic tomatoes", The Plant J., vol. 3, 1993, pp. 121-129.
Harriman et al: "Molecular cloning of tomato pectin methylesterase gene and its expression in Rutgers, ripening inhibitor, nonripening and never ripe tomato fruits", Plant Physiol., vol. 97, 1991, pp. 80-87.
Markovic et al: "Tomato and Aspergillus niger pectinesterases", Protein Seq. Data Anal., vol. 3, 1990, pp. 513-515.
Bird Colin Roger
Burridge Brett Eric
Tucker Gregory Alan
Zhang Jianliang
Lau Kawai
Zeneca Limited
LandOfFree
DNA encoding a pectin esterase, cells and plants derived therefr does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with DNA encoding a pectin esterase, cells and plants derived therefr, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and DNA encoding a pectin esterase, cells and plants derived therefr will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1684285