Expression of the cry9Aa2 B.t. gene in tobacco chloroplasts confers resistance to potato tuber moth.
We report here the control of potato tuber moth (Phthorimaea operculella) by incorporating a truncated Bacillus thuringiensis cry9Aa2 gene in the plastid genome. Plasmids pSKC84 and pSKC85 are derivatives of a new polycistronic plastid transformation vector, pPRV312L, that carries spectinomycin resistance (aadA) as a selective marker and targets insertions in the trnI-trnA intergenic region. The Cry9Aa2 N-terminal region (82.1 kDa; 734 amino acids) was expressed in a cassette, which consists of 49 nucleotides of the cry9Aa2 leader and the 3'-untranslated region of the plastid rbcL gene (TrbcL), and relies on readthrough transcription from the plastid rRNA operon. In a tobacco leaf bioassay, expression of Cry9Aa2 conferred resistance to potato tuber moth. In accordance, the Cry9Aa2 insecticidal protein accumulated to high levels, approximately 10% of the total soluble cellular protein and approximately 20% in the membrane fraction. However, high-level Cry9Aa2 expression significantly delayed plant development. Thus, a practical system to control potato tuber moth by Cry9Aa2 expression calls for down-regulation of its expression.
Chakrabarti
Swarup Kumar
SK
Central Potato Research Institute, Shimla, 171001 HP, India.
Lutz
Kerry Ann
KA
Lertwiriyawong
Benjawan
B
Svab
Zora
Z
Maliga
Pal
P
D000818:Animals; D001413:Bacillus thuringiensis / Q000235:genetics*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001427:Bacterial Toxins / Q000235:genetics* / Q000378:metabolism; D001681:Biological Assay; D002736:Chloroplasts / Q000378:metabolism*; D004731:Endotoxins / Q000235:genetics* / Q000378:metabolism; D005821:Genetic Techniques; D005822:Genetic Vectors; D006460:Hemolysin Proteins / Q000235:genetics* / Q000378:metabolism; D007313:Insecta; D009036:Moths / Q000378:metabolism*; D010572:Pest Control, Biological / Q000379:methods*; D010935:Plant Diseases / Q000235:genetics*; D030821:Plants, Genetically Modified; D018087:Plastids / Q000378:metabolism; D011198:Solanum tuberosum; D014026:Nicotiana / Q000235:genetics* / Q000378:metabolism
D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis