Regulatory sequences for modulating transgene expression in plants
The invention relates to gene expression regulatory sequences, specifically introns that act as enhancers of gene expression, the promoter and terminator sequences endogenously associated with these introns. Presence of these intronic enhancer sequences in proximity to promoter sequences leads to enhancement of gene expression. Methods of finding such new intronic enhancer sequences and using them to generate transgenic plants are also described.
1. A recombinant DNA construct comprising: (a) an intron operably linked to a promoter, (b) a heterologous polynucleotide, and (c) a terminator, wherein the intron comprises a nucleotide sequence that has at least 98% sequence identity to SEQ ID NO: 13, and wherein the intron comprises at least one copy of a nucleotide sequence of SEQ ID NO: 100.
2. The recombinant DNA construct of claim 1 , wherein the intron comprises the nucleotide sequence of SEQ ID NO: 13.
3. The recombinant DNA construct of claim 1 , wherein the intron enhances expression of the heterologous polynucleotide in a plant.
4. The recombinant DNA construct of claim 1 , wherein the intron is capable of enhancing expression of a heterologous polynucleotide in a monocotyledonous plant when compared to a corresponding recombinant DNA construct without the intron.
5. A plant comprising the recombinant DNA construct of claim 3 .
6. A seed comprising the recombinant DNA construct of claim 3 .
7. A method for modulating transgene expression in a plant comprising the steps of:
(a) introducing into a regenerable plant cell the recombinant DNA construct of claim 1 ;
(b) regenerating a transgenic plant from the regenerable plant cell after step (a) wherein the transgenic plant comprises the recombinant DNA construct; and
(c) obtaining a progeny plant derived from the transgenic plant of step (b), wherein the progeny plant comprises the recombinant DNA construct and exhibits enhanced transgene expression when compared to a plant comprising in its genome the recombinant DNA construct without the corresponding intron sequence.
8. The method of claim 7 wherein said plant is a monocot.
9. The recombinant DNA construct of claim 1 , wherein said promoter is a constitutive promoter, a tissue-preferred promoter, an inducible promoter, or a developmentally regulated promoter.