Method for transformation of grasses
The invention provides methods for transforming grass plants with Agrobacterium . The invention allows creation of transgenic grass plants without the need for callus as a target tissue for transformation, thus providing a rapid method for the production of transgenic grass plants. Transgenic grass plants produced by this method are also provided.
1. A method of transforming a grass plant cell comprising contacting a non-stolon or non-rhizome nodal explant, or an inflorescence explant, from a grass plant with an Agrobacterium comprising a DNA of interest, wherein the explant is contacted with the Agrobacterium without first forming a callus culture of cells from the explant, wherein at least a first cell of the explant is transformed with the DNA of interest; wherein the grass plant is switchgrass and wherein the explant is excised from the plant prior to contacting the explant with the Agrobacterium.
2. The method of claim 1 , further comprising regenerating a switchgrass plant from the cell.
3. The method of claim 2 , wherein regenerating a switchgrass plant comprises culturing the explant after contacting the explant with Agrobacterium to induce formation of roots or shoots; allowing roots or shoots to form from the explant; and cultivating the explant under plant growth conditions to produce a transgenic grass plant comprising the DNA of interest.
4. The method of claim 3 , further comprising growing said plant to sexual maturity and obtaining a transgenic seed therefrom.
5. The method of claim 1 , wherein said DNA of interest comprises a polynucleotide encoding a polypeptide, antisense construct or siRNA construct.
6. The method of claim 5 , wherein the polynucleotide is operably linked to a promoter functional in grass plants.
7. The method of claim 6 , wherein the promoter is a constitutive promoter, inducible promoter or tissue specific promoter.
8. The method of claim 5 , wherein the polynucleotide confers a trait selected from the group consisting of herbicide resistance, insect resistance, disease resistance, pest resistance, improved nutritional quality, modified carbohydrate metabolism, modified lipid metabolism, increased biomass, altered lignin content, increased plant digestibility, increased biomass digestibility, altered lignin biosynthesis and modified fermentable carbohydrate content.
9. The method of claim 5 , wherein the polypeptide comprises a selectable marker or a screenable marker.
10. The method of claim 9 , wherein the selectable marker confers resistance to a selective agent.
11. The method of claim 10 , further comprising contacting the explant with the selective agent and selecting an explant with tolerance to the agent.
12. A method of producing food, feed or biomass comprising (a) obtaining a plant by the method of claim 2 ; and (b) producing food, feed or biomass from the plant or part thereof.
13. A method of plant breeding comprising (a) obtaining a plant by the method of claim 2 ; and (b) crossing said plant with a second switchgrass plant.