Insect viruses and their uses in protecting plants

Abstract

The present invention relates to an isolated small RNA virus capable of infecting insect species including Heliothis species, and to the nucleotide sequences and proteins encoded thereby. The invention contemplates uses of the virus in controlling insect attack in plants.

1 - 32 . (canceled)  
     
     
         33 . A capsovector comprising a capsid protein of a small RNA insect virus wherein said capsid protein is assembled into a viral capsid encapsidating an exogenous nucleic acid, wherein following ingestion of the capsovector by an insect, the assembled capsid protects the exogenous nucleic acid from inactivation in the insect gut, and wherein said small RNA insect virus belongs to the family of Picornaviridae, Tetraviridae or Nodaviridae and which possesses a gene encoding a capsid protein that provides all of the sequence information required for viral capsid assembly, encapsidation of viral RNA, binding of viral capsid to host insect cells, and release of viral RNA for translation in-host insect cells.  
     
     
         34 . A capsovector as claimed in  claim 33  in which the small RNA insect virus is  Helicoverpa armigera  stunt virus.  
     
     
         35 . A capsovector as claimed in  claim 33  in which the capsid protein is P71 (SEQ ID NO:50).  
     
     
         36 . A capsovector as claimed in  claim 33  in which the capsovector comprises a further nucleic acid sequence, the further nucleic acid sequence encoding the capsid protein.  
     
     
         37 . A capsovector as claimed in  claim 33  in which the small RNA insect virus belongs to the family Tetraviridae.  
     
     
         38 . A capsovector as claimed in  claim 33  in which the exogenous nucleic acid is RNA.  
     
     
         39 . A capsovector as claimed in  claim 38  in which the RNA is partly or completely double stranded RNA.  
     
     
         40 . A capsovector as claimed in  claim 33  in which the exogenous nucleic acid can act as a template for the production of double stranded RNA.  
     
     
         41 . A capsovector as claimed in  claim 39  or  claim 40  in which the double stranded RNA has a stem-loop structure.  
     
     
         42 . A capsovector as claimed in  claim 33  which is produced by a transgenic plant.  
     
     
         43 . A plant cell comprising a capsovector as claimed in  claim 33 .  
     
     
         44 . A transgenic plant comprising a plant cell as claimed in  claim 33 .  
     
     
         45 . A method of delivering an exogenous nucleic acid to an insect, the method comprising feeding or otherwise contacting an insect with a capsovector of  claim 33 .  
     
     
         46 . A method of producing a capsovector as claimed in  claim 33 , the method comprising; 
 i) providing an expression system comprising a first polynucleotide sequence encoding the capsid protein and a second polynucleotide sequence comprising the exogenous nucleic acid,    ii) expressing the first polynucleotide sequence resulting in the production of capsid proteins,    iii) allowing the capsid proteins to assemble into viral capsids encapsidating the exogenous nucleic acid, thereby producing said capsovector.    
     
     
         47 . The method as claimed in  claim 46 , wherein the first polynucleotide sequence and the second polynucleotide sequence form part of a single nucleic acid molecule.  
     
     
         48 . The method as claimed in  claim 46 , wherein the first polynucleotide sequence does not form part of the capsovector.  
     
     
         49 . The method as claimed in  claim 46 , wherein the exogenous nucleic acid is RNA.  
     
     
         50 . The method as claimed in  claim 46 , wherein the exogenous nucleic acid can act as a template for the production of double stranded RNA.