Down-regulating gene expression in insect plants

Abstract

The present invention relates to the prevention and/or control of infestation by insect pest species. In particular, the invention relates to down-regulation of expression of target genes in insect pests using interfering ribonucleic acid (RNA) molecules. Also described are transgenic plants that (i) express or are capable of expressing interfering RNAs of the invention and (ii) are resistant to infestation by insect pest species. Compositions containing the interfering RNAs of the invention are also provided.

What is claimed: 
     
         1 . An interfering ribonucleic acid (RNA) molecule which comprises at least one double-stranded region, wherein said double-stranded region comprises a sense RNA strand annealed by complementary basepairing to an antisense RNA strand, wherein the interfering RNA molecule upon uptake by an insect pest species is toxic to the insect pest species, wherein the interfering RNA molecule is encoded by a nucleic acid molecule comprising:
 (i) a nucleotide sequence that is at least 85% identical to any of SEQ ID NOs: 1, 21, or the complement thereof;   (ii) a nucleotide sequence comprising at least 21 contiguous nucleotides of any of SEQ ID NOs: 1, 21, or the complement thereof;   (iii) a nucleotide sequence that is at least 21 contiguous nucleotides and encodes an amino acid sequence that is encoded by al least 21 contiguous nucleotides of any of SEQ ID NOs: 1 or 21; or   (iv) a nucleotide sequence that is at least 21 contiguous nucleotides and encodes an amino acid sequence that is at least 7 contiguous amino acids and is represented in SEQ ID NO: 206.   
     
     
         2 . The interfering RNA of  claim 1 , wherein the RNA comprises at least one silencing element, wherein the silencing element comprises a sequence of nucleotides which is at least partially complementary to a target nucleotide sequence within the tetraspanin 2A protein target gene. 
     
     
         3 . The interfering RNA of  claim 2 , wherein the silencing element comprises a sequence of al least 21 contiguous nucleotides which is at least partially complementary to a target nucleotide sequence within the tetraspanin 2A protein target gene. 
     
     
         4 . The interfering RNA of  claim 2 , wherein the silencing element is a region of double-stranded RNA comprising annealed complementary strands, one strand of which comprises a sequence of nucleotides which is al least partially complementary to a target nucleotide sequence within the tetraspanin 2A protein target gene. 
     
     
         5 . The interfering RNA of  claim 2  wherein the RNA comprises at least two silencing elements, wherein each silencing element comprises a sequence of nucleotides which is at least partially complementary to a target nucleotide sequence within a tetraspanin 2A protein target gene. 
     
     
         6 . The interfering RNA of  claim 5  wherein each of the silencing elements comprises a different sequence of nucleotides which is complementary to a different target nucleotide sequence. 
     
     
         7 . The interfering RNA of  claim 6  wherein the different target nucleotide sequences originate from a single tetraspanin 2A protein target gene. 
     
     
         8 . The interfering RNA of  claim 6  wherein the different target nucleotide sequences originate from different target genes. 
     
     
         9 . The interfering RNA of  claim 8  wherein the different target genes originate from the same insect pest species. 
     
     
         10 . The interfering RNA of  claim 8  wherein the different target genes originate from different insect pest species. 
     
     
         11 . The interfering RNA of  claim 1  wherein the insect pest species is a plant pest. 
     
     
         12 . The interfering RNA of  claim 11  wherein the plant pest is selected from the  Lygus  genus or the  Leptinotarsa  genus. 
     
     
         13 . The interfering RNA of  claim 12  wherein the plant pest is from the  Lygus  genus and is  Lygus hesperus , or wherein the plant pest is from the  Leptinotarsa  genus and is  Leptinotarsa decemlineata.    
     
     
         14 . The interfering RNA of  claim 1  wherein the tetraspanin 2A protein target gene is an essential pest gene such that down-regulating expression causes decreased growth, development, reproduction, or survival of the pest as compared with pest species exposed to an interfering ribonucleic acid targeting a non-essential gene or an interfering ribonucleic acid that does not down-regulate any genes within the pest species. 
     
     
         15 . An isolated polynucleotide encoding the interfering RNA of  claim 1 . 
     
     
         16 . A DNA construct comprising the polynucleotide of  claim 15 . 
     
     
         17 . The DNA construct of  claim 16  wherein the construct is an expression construct and wherein the polynucleotide is operably linked to at least one regulatory sequence capable of driving expression of the polynucleotide. 
     
     
         18 . A host cell comprising an interfering RNA of  claim 1 , a polynucleotide encoding the interfering RNA of  claim 1 , or a DNA construct comprising a polynucleotide encoding the interfering RNA of  claim 1 . 
     
     
         19 . The host cell of  claim 18  wherein the host cell is a prokaryotic or a eukaryotic cell.