Insect resistant tomato | BCH-LMO-SCBD-15396 | Living Modified Organism | Biosafety Clearing-House


Living Modified Organism (LMO)

Decisions on the LMO Risk Assessments  
last updated: 15 Apr 2013
Living Modified Organism identity
The image below identifies the LMO through its unique identifier, trade name and a link to this page of the BCH. Click on it to download a larger image on your computer. For help on how to use it go to the LMO quick-links page.
Insect resistant tomato
Tomato was modified for resistance against certain tomato feeding Lepidopteran insects via the insertion of a copy of the Cry1Ac gene.
The term “Recipient organism” refers to an organism (either already modified or non-modified) that was subjected to genetic modification, whereas “Parental organisms” refers to those that were involved in cross breeding or cell fusion.
Characteristics of the modification process
  • Agrobacterium-mediated DNA transfer
Some of these genetic elements may be present as fragments or truncated forms. Please see notes below, where applicable.
  • BCH-GENE-SCBD-14986-6 Cry1Ac | Bacillus thuringiensis (Bt, Bacillus, BACTU)
    Protein coding sequence | Resistance to diseases and pests (Insects, Lepidoptera (butterflies and moths))
  • BCH-GENE-SCBD-100287-7 CaMV 35S promoter | Cauliflower mosaic virus (CaMV)
  • BCH-GENE-SCBD-15001-5 Neomycin Phosphotransferase II | Escherichia coli (ECOLX)
    Protein coding sequence | Resistance to antibiotics (Kanamycin)
  • BCH-GENE-SCBD-100269-8 Nopaline Synthase Gene Terminator | Agrobacterium tumefaciens (Agrobacterium)
  • BCH-GENE-SCBD-100366-6 CaMV Enhanced 35S promoter | Cauliflower mosaic virus (CaMV)
  • BCH-GENE-SCBD-103856-6 α' subunit of β-conglycinin gene terminator | Glycine max (Soybean, Soya bean, Soya, SOYBN)
The Cry1Ac coding sequence was modified for plant optimised codons and resulted in a single amino acid change at L766S.

Southern blot analysis indicated that a single intact copy of the T-DNA was inserted into the host genome
LMO characteristics
  • Food
Detection method(s)
Additional Information
Insect-resistant tomato line 5345 was developed using recombinant DNA techniques to express the insecticidal protein, Cry1Ac, encoded by the cry1Ac gene from the soil bacterium Bacillus thuringiensis subsp. kurstaki strain HD73.

Insecticidal activity is caused by the selective binding of Cry1Ac protein to specific sites localized on the brush border midgut epithelium of susceptible lepidopteran species. Following binding, cation-specific pores are formed that disrupt midgut ion flow thereby causing gut paralysis and eventual death from bacterial sepsis.

Delta-endotoxins, such as the Cry1Ac protein expressed in tomato line 5345, exhibit highly selective insecticidal activity against a narrow range of lepidopteran pests. The specificity of action is directly attributable to the presence of specific receptors in the target insects. There are no receptors for delta-endotoxins of B. thuringiensis on the surface of mammalian intestinal cells, therefore, livestock animals and humans are not susceptible to these proteins.