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
Reexamination Certificate
1998-06-22
2001-03-27
Fox, David T. (Department: 1638)
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
C800S274000, C800S278000, C800S287000, C536S023600, C536S024100, C435S069100, C435S320100, C435S419000, C435S468000
Reexamination Certificate
active
06207883
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to recombinant, isolated and other synthetic DNA useful in male-sterility systems for plants. In particular, the invention relates to a gene associated with male fertility, labelled Ms41-A, and a recessive mutant form thereof, labelled ms41-A, which confers male sterility. Male-sterile plants are useful for the production of hybrid plants by sexual hybridisation.
Hybrid plants have the advantages of higher yield and better disease resistance than their parents, because of heterosis or hybrid vigour. Crop uniformity is another is advantage of hybrid plants when the parents are extensively homozygous; this leads to improved crop management. Hybrid seed is therefore commercially important and sells at a premium price.
Producing a hybrid plant entails ensuring that the female parent does not self-fertilise. There have been many prior proposals, mechanical, chemical and genetic, for preventing self-pollination. Among the genetic methods is the use of anther-specific genes or their promoters to disrupt the normal production of pollen grains. An anther-specific promoter, for example, can be used to drive a “male-sterility DNA” at the appropriate time and in the right place. Male sterility DNAs include those coding for lytic enzymes, including those that lyse proteins, nucleic acids and carbohydrates. Glucanases are enzymes which break down carbohydrates.
WO-A-9302197 describes recombinant or isolated DNA encoding a glucanase called callase.
Aarts et al, (
Nature
, 363:715-717 (7993)) have described a gene required for male fertility, isolated from Arabidopsis, which has been labelled Ms2.
We have now identified and isolated from Arabidopsis another gene linked to male fertility. This gene has been labelled Ms41-A. Its mutant , recessive, form is labelled ms41-A and is capable of conferring male sterility. This gene would appear to offer advantages over Ms2 when used to produce male sterile plants.
SUMMARY OF THE INVENTION
Thus, in a first aspect the present invention provides recombinant or isolated Nucleic acid which:
a) encodes the Ms41-A protein from Arabidopsis;
b) encodes a Ms41-A like protein;
c) encodes the ms41-A protein from Arabidopsis;
d) encodes a ms41-A like protein;
e) comprises a promoter sequence which regulates expression of the Ms41-A protein from Arabidopsis or a promoter sequence which regulates expression of a Ms41-A like protein; or
f) hybridises under stringent conditions to Nucleic acid a), b), c), d) or e) or would do so but for the degeneracy of the genetic code.
In one embodiment of a) above, the Nucleic acid encodes a protein having an amino acid squence as shown in FIG.
4
. Although
FIG. 4
relates only to a protein of
Arabidopsis, those skilled in the art will readily be able to identify equivalent proteins from other members of the family Brassicaceae or indeed similar proteins from other commercially important plant families, ie Ms41-A like proteins.
In turn the equivalent genes may be identified by hybridisation studies, restriction fragment length polymorphism (RFLP), degenerate PCR and other methods known in the art. Genes or other DNA sequences, whether natural, engineered or synthetic, encoding closely equivalent proteins may for example hybridise under stringent conditions (such as at approximately 35° C. to 65° C. in a salt solution of approximately 0.9 molar) to the Arabidopsis gene, or fragments of it of, for example, 10, 20, 50 or 100 nucleotides. A 15-20 nucleotide probe would be appropriate under many circumstances.
In the context of the present invention, “Nucleic acid which encodes” includes all nucleic acid, eg DNA sequences which will, when expressed, give rise to the protein. Examples of such DNA sequences include, but are not limited to, ones which comprise non-coding regions, e.g introns, sequences which include leader sequences and/or signal sequences, or simply comprise a coding sequence for the protein. The skilled person will also appreciate that, due to codon degeneracy, there will, for example, be a number of DNA sequences capable of coding for the Ms41-A protein or a Ms41-A like protein.
In general, the Nucleic acid of the invention will comprise at least a direct coding sequence for the protein as well as a promoter and transcription termination sequence. The promoter can itself comprise only chose sequences, or elements, necessary for the correct initiation of transcription (which regions can be described as transcription initiation regions, or instance), or, alternatively, it can include regions or sequence which are not directly involved in the initiation of transcription, i.e. a complete promoter can be employed.
A preferred coding sequence described in this specification is from Arabidopsis and can be isolated by methods known in the art, for example by (a) synthesising cDNA from mRNA isolated from Arabidopsis, (b) isolating this cDNA. This cDNA can, in turn, be used (c) as a probe to identify regions of the plant genome of a chosen member of another plant species, eg Maize, that encode mRNA of interest and (d) identifying the upstream (5′) regulatory regions that contain the promoter of this DNA.
A particularly preferred DNA sequence is that shown in
FIG. 3
, and more particularly, the sequence shown in
FIG. 3
which commences with the base pair labelled 1, as will subsequently be described in the examples. Those skilled in the art will, with the information given in this specification, be able to identify with sufficient precision the coding regions and to isolate and/or recombine DNA containing them.
The Nucleic acid of the invention can be used to confer male sterility on plants. For instance, the recessive form of the gene, ie ms41-A can be used to transform a plant. Alternatively, the dominant form, ie Ms41-A can be downregulated in some way.
As discussed herein, the Nucleic acid can include a promoter, and to increase the likelihood of male sterility being conferred it is possible to use promoters which drive expression in particular plant tissues which are involved in the control of fertility. Examples of such promoters are those which are tapetum-specific, for example a Brassicaceae A3 or A9 promoter, described in WO-A-9211379, and the A6 promoter described in WO-A-9302197. Both WO-A-9211379 and WO-A-9302197 are hereby incorporated by reference.
Because of the natural specificity of the regulation of expression of the Ms41-A or Ms41-A like gene, it is not necessary for the Ms41-A promoter to be linked to specific disrupter DNA to provide a useful male-sterility system (although it can be); non-specific disrupter DNA can be used.
Ms41-A like promoters from other plant species, eg from Maize, and modified Ms41-A promoters can be used, and if necessary located or identified and isolated as described above or the Ms41-A coding sequences, mutatis murandis. Ms41-A or Ms41-A like promoter-containing DNA in accordance with the invention can, as indicated above, be used to confer male sterility on plants, particularly those belonging to the family Brassicaceae, in a variety of ways as will be discussed below. In an important embodiment of the invention, therefore, a promoter as described above is operatively linked to DNA which, when expressed, causes male sterility.
Since an effective sterility system is complete, propagation of the seed parent must proceed either by asexual means or via the pollination of the male-sterile by an isogenic male-fertile line, and the subsequent identification or selection of male sterile plants among the offspring. Where vegetative propagation is practical, the present invention forms a complete system for hybrid production. Where fertility restoration is necessary to produce a seed crop, the present invention forms the basis of a new male sterility system. In some seed crops where the level of cross pollination is high, seed mixtures may enable restoration to be bypassed. The male sterility will be particularly useful in crops where restoration of fertility is not required, such as in the vegetable Brassica spp., and such other edib
Baudot Gaelle
Garcia Denise
Hodge Rachel
Perez Pascual
Cooper & Dunham LLP
Fox David T.
Gene Shears Pty. Ltd.
White John P.
LandOfFree
DNA sequences coding for a protein conferring male sterility 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 sequences coding for a protein conferring male sterility, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and DNA sequences coding for a protein conferring male sterility will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2544591