Multicellular living organisms and unmodified parts thereof and – Method of introducing a polynucleotide molecule into or... – The polynucleotide contains a tissue – organ – or cell...
Reexamination Certificate
1998-04-28
2001-03-06
Fox, David T. (Department: 1638)
Multicellular living organisms and unmodified parts thereof and
Method of introducing a polynucleotide molecule into or...
The polynucleotide contains a tissue, organ, or cell...
C435S069100, C435S320100, C435S419000, C435S468000, C536S023600, C536S024100, C800S278000, C800S290000, C800S306000
Reexamination Certificate
active
06198024
ABSTRACT:
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The present invention relates generally to plant molecular biology and genetic engineering and more specifically to the production of genetically modified seed plants in which the natural process of dehiscence is delayed.
BACKGROUND INFORMATION
Rapeseed is one of the most important oilseed crops after soybeans and cottonseed, representing 10% of the world oilseed production in 1990. Rapeseed contains 40% oil, which is pressed from the seed, leaving a high-protein seed meal of value for animal feed and nitrogen fertilizer. Rapeseed oil, also known as canola oil, is a valuable product, representing the fourth most commonly traded vegetable oil in the world.
The production of oilseeds, meal and oil from rapeseed plants has been increasing continuously for the last 30 years for food and feed grains, mainly by expansion of the area under cultivation. Most northern European countries produce rapeseed as their main edible oil crop. By the year 2000, China is expected to be the leading producer with 9.2 metric tons (Mt; 26%); followed by India with 7.8 Mt (22%); the European Community (12 countries), with 7.6 Mt (21%); Canada, 3.8 Mt (11%) and eastern Europe with 2.6 Mt (7%).
Unfortunately, the yield of seed from rapeseed and related plants is limited by pod dehiscence, which is a process that occurs late in fruit development whereby the pod is opened and the enclosed seeds released. Degradation and separation of cell walls along a discrete layer of cells dividing the two halves of the pod, termed the “dehiscence zone,” result in separation of the two halves of the pod and release of the contained seeds. Seed “shattering,” whereby seeds are prematurely shed through dehiscence before the crop can be harvested, is a significant problem faced by commercial seed producers and represents a loss of income to the industry. Adverse weather conditions can exacerbate the process of dehiscence, resulting in greater than 50% loss of seed yield.
Attempts to solve this problem over the past 20 years have focused on the breeding of shatter-resistant varieties. However, these plant hybrids are frequently sterile and lose favorable characteristics that must be regained by backcrossing, which is both time-consuming and laborious. Other strategies to alleviate pod shattering include the use of chemicals such as pod sealants or mechanical techniques such as swathing to reduce wind-stimulated shattering. To date, however, a simple method for producing genetically modified seed plants that do not open and release their seeds prematurely has not been described.
Thus, a need exists for identifying genes that regulate the dehiscence process and for developing genetically modified seed plant varieties in which the natural seed dispersal process is delayed. The present invention satisfies this need and provides related advantages as well.
SUMMARY OF THE INVENTION
The present invention provides a non-naturally occurring seed plant that is characterized by delayed seed dispersal due to ectopic expression of a nucleic acid molecule encoding an AGL8-like gene product. The AGL8-like gene product can have, for example, substantially the amino acid sequence of an AGL8 ortholog such as Arabidopsis AGL8 (SEQ ID NO:2). Particularly useful seed plants of the invention, which are characterized by delayed seed dispersal, include members of the Brassicaceae, such as rapeseed, and members of the Fabaceae, such as soybeans, peas, lentils and beans.
In one embodiment, the invention provides a transgenic seed plant that is characterized by delayed seed dispersal due to ectopic expression of a nucleic acid molecule encoding an AGL8-like gene product. In a transgenic seed plant of the invention, the nucleic acid molecule encoding the AGL8-like gene product can be operatively linked to an exogenous regulatory element. Useful exogenous regulatory elements include constitutive regulatory elements and dehiscence zone-selective regulatory elements. In particular, the exogenous regulatory element can be a dehiscence zone-selective regulatory element that is an AGL1 regulatory element or an AGL5 regulatory element.
In another embodiment, the invention provides a non-naturally occurring seed plant that is characterized by delayed seed dispersal due to suppression of both AGL1 and AGL5 expression in the seed plant. Such a non-naturally occurring seed plant characterized by delayed seed dispersal can be, for example, an agl1 agl5 double mutant.
The present invention further provides a tissue derived from a non-naturally occurring seed plant of the invention. In one embodiment, the invention provides a tissue derived from a non-naturally occurring seed plant that has an ectopically expressed nucleic acid molecule encoding an AGL8-like gene product and is characterized by delayed seed dispersal. In another embodiment, the invention provides a tissue derived from a non-naturally occurring seed plant in which AGL1 expression and AGL5 expression each are suppressed, where the seed plant is characterized by delayed seed dispersal.
Methods of producing a non-naturally occurring seed plant characterized by delayed seed dispersal also are provided herein. Such methods entail ectopically expressing a nucleic acid molecule encoding an AGL8-like gene product in the seed plant, whereby seed dispersal is delayed due to ectopic expression of the nucleic acid molecule.
The invention also provides a substantially purified dehiscence zone-selective regulatory element, comprising a nucleotide sequence that confers selective expression upon an operatively linked nucleic acid molecule in the valve margin or dehiscence zone of a seed plant, provided that the dehiscence zone-selective regulatory element does not have a nucleotide sequence consisting of nucleotides 1889 to 2703 of SEQ ID NO:4. The dehiscence zone-selective regulatory element can be, for example, an AGL1 regulatory element or AGL5 regulatory element.
Further provided is a plant expression vector containing a dehiscence zone-selective regulatory element that confers selective expression upon an operatively linked nucleic acid molecule in the valve margin or dehiscence zone of a seed plant, provided that the dehiscence zone-selective regulatory element does not have a nucleotide sequence consisting of nucleotides 1889 to 2703 of SEQ ID NO:4. If desired, a plant expression vector can contain a nucleic acid molecule encoding an AGL8-like gene product in addition to the dehiscence zone-selective regulatory element.
The invention also provides a kit for producing a transgenic seed plant characterized by delayed seed dispersal, such kit containing a dehiscence zone-selective regulatory element that confers selective expression upon an operatively linked nucleic acid molecule in the valve margin or dehiscence zone of a seed plant, provided that said dehiscence zone-selective regulatory element does not have a nucleotide sequence consisting of nucleotides 1889 to 2703 of SEQ ID NO:4. In a kit of the invention, the dehiscence zone-selective regulatory element can be, if desired, operatively linked to a nucleic acid molecule encoding an AGL8-like gene product.
REFERENCES:
patent: WO 94/23043 (1994-10-01), None
patent: WO 97/13865 (1997-04-01), None
patent: WO 98/22592 (1998-05-01), None
Kim et al, Plant Mol. Biol., vol. 24, pp. 105-117, 1994.
Savidge et al, Plant Cell, vol. 7, pp. 721-733, 1995.
Coupe et al., “Identification and characterization of a proline-rich mRNA that accumulates during pod development in oilseed rape (Brassica napusL.),”Plant Mol. Biol.23:1223-1232 (1993).
Erskine, “Selection for Pod Retention and Pod Indehiscence in Lentils,”Euphytica34:105-112 (1985).
Flanagan et al., “Specific expression of the AGL1 MADS-box gene suggests regulatory functions inArabidopsis gynoeciumand ovule development,”The Plant Journal10:343-353 (1996).
Gillaspy et al., “Fruits: A Development Perspective,”The Plant Cell5:1439-1451 (1993).
Gu et al., “The Fruitfull MADS-box gene mediates cell differentiation during Arabidopsis fruit development,”Development125:1
Ferrandiz Cristina
Yanofsky Martin F.
Fox David T.
Mehta Ashwin D.
The Regents of the University of California
Townsend & Townsend & Crew LLP
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