Methods and DNA Constructs for Autoregulating Transgene Silencing

Abstract

This invention provides a method to autoregulate expression of a transgene susceptible to sRNA silencing by concomitantly transcribing RNA from DNA of a transgene and RNA from DNA from at least one sRNA silencing pathway gene. An aspect of the invention provides use of a recombinant DNA construct that includes DNA of a transgene and DNA of an sRNA silencing regulator. Also disclosed are transgenic cells and organisms having in their genome a recombinant DNA construct that includes DNA of a transgene and DNA of an sRNA silencing regulator.

What is claimed is: 
     
         1 . A method to autoregulate expression of a transgene susceptible to sRNA silencing by concomitantly transcribing RNA from DNA of said transgene and RNA from DNA from at least one sRNA silencing pathway gene. 
     
     
         2 . The method of  claim 1  wherein initiation of sRNA silencing of said transgene causes sRNA silencing of said at least one sRNA silencing pathway gene whereby expression of said transgene becomes less susceptible to sRNA silencing. 
     
     
         3 . The method of  claim 1 , wherein said at least one sRNA silencing pathway gene is selected from the group consisting of RDR6, SDE3, RDR2, WEX, SGS3, DCL2-4, UPF1, UPF3, HEN1, NRPD1A, NRPD2, DRD1, HDA6, MOP1, and AGO1. 
     
     
         4 . The method of  claim 1  wherein said transgene is DNA that transcribes to an mRNA encoding a protein or to a non-coding RNA. 
     
     
         5 . The method of  claim 1  wherein transcription occurs in a plant cell. 
     
     
         6 . The method of  claim 5  wherein said transgene comprises DNA encoding a protein that imparts herbicide tolerance or pest tolerance to a plant. 
     
     
         7 . The method of  claim 6  wherein said protein that imparts herbicide tolerance is selected from the group consisting of EPSP synthase, glyphosate oxido-reductase, phosphinothricin acetyltransferase, mutant acetolactate synthase, haloarylnitrilase, acetyl-coenzyme A carboxylase, modified dihydropteroate synthase, glyphosate-N-acetyl transferase, dicamba mono-oxygenase, glyphosate decarboxylase, and 2,2-dichloropropionic acid dehalogenase. 
     
     
         8 . The method of  claim 6  wherein said protein that imparts pest tolerance is selected from the group consisting of  Bacillus thuringiensis  Cry1A(b) endotoxin,  Bacillus thuringiensis  Cry2Aa endotoxin,  Bacillus thuringiensis  Cry3A endotoxin, ET29 and TIC810 endotoxins, RNA that becomes a dsRNA targeting a vacuolar ATPase gene of soybean cyst nematode, and RNA that becomes a dsRNA targeting a soybean cyst nematode major sperm protein. 
     
     
         9 . The method of  claim 5  wherein said transcribed RNA of said plant cell is in a pest having ingested part or all of said plant cell, or in a pathogen infecting part or all of said plant cell. 
     
     
         10 . A recombinant DNA construct comprising a transgene and an sRNA silencing regulator wherein said sRNA silencing regulator comprises DNA from at least one sRNA silencing pathway gene. 
     
     
         11 . The recombinant DNA construct of  claim 10  further comprising a promoter that concomitantly transcribes said transgene and said sRNA silencing regulator. 
     
     
         12 . The recombinant DNA construct of  claim 10  wherein said at least one sRNA silencing pathway gene is selected from the group consisting of RDR6, SDE3, RDR2, WEX, SGS3, DCL2-4, UPF1, UPF3, HEN1, NRPD1A, NRPD2, DRD1, HDA6, MOP1 and AGO1. 
     
     
         13 . The recombinant DNA construct of  claim 10  wherein said sRNA silencing regulator is located within at least one of:
 a) a region 5′ to said transgene, 
 b) a region 3′ to said transgene, and 
 c) a region within said transgene. 
 
     
     
         14 . A recombinant cell having in its genome the recombinant DNA construct of  claim 10 . 
     
     
         15 . The recombinant DNA construct of  claim 10  stably integrated into the genome of a cell. 
     
     
         16 . The recombinant DNA construct of  claim 10  in plant biomass, plant meal, plant seed, plant leaves, plant flour, plant stalk, or plant cell prepared from a transgenic plant having said recombinant DNA construct in its genome. 
     
     
         17 . A transgenic plant comprising a regenerated transgenic plant prepared from said recombinant cell of  claim 10 , or a progeny transgenic plant of said regenerated transgenic plant. 
     
     
         18 . A transgenic organism comprising a recombinant cell having in its genome the recombinant DNA construct of  claim 10 . 
     
     
         19 . A transgenic plant comprising a recombinant cell having in its genome the recombinant DNA construct of  claim 10 .