BioCassava Pro-vitamin A cassava | BCH-LMO-SCBD-263490 | Living Modified Organism | Biosafety Clearing-House


Living Modified Organism (LMO)

Decisions on the LMO Risk Assessments  
last updated: 10 Mar 2023
Living Modified Organism identity
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BioCassava Pro-vitamin A cassava
The cassava (Manihot esculenta) was modified for increased pro-vitamin A (trans beta-carotene) content through the expression of Pantoea ananas phytoene desaturase and Arabidopsis thaliana 1-deoxy-D-xylulose-5-phosphate synthase. Phytoene synthase directs the flux of geranylgeranyl diphosphate into carotenoid biosynthesis, while 1-deoxy-D-xylulose-5-phosphate synthase, which is a rate limiting step in the overall pathway, catalyzes the first step in isoprenoid and carotenoid biosynthesis. Overall, up-regulating the total flux in the isoprenoid pathway and to enhance the flux of isoprenoids into carotenoid synthesis results in a high accumulation of provitamin A in tuber tissues. The modified cassava also expresses Escherichia coli neomycin phosphotransferase II, which was a kanamycin or neomycin selectable marker during transformation.

Please note that the transformation event is tentatively assigned and is to be confirmed.
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.
Variety 60444
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-100273-4 B33 gene promotor | Solanum tuberosum (Potato, SOLTU)
  • BCH-GENE-SCBD-263476-1 Δ4 acyl-ACP desaturase transit peptide | Coriandrum sativum (Coriander, Cilantro, Dhania, Chinese parsley)
    Transit signal
  • BCH-GENE-SCBD-103621-3 Phytoene Desaturase gene | Erwinia uredovora (PANAN)
    Protein coding sequence | Changes in quality and/or metabolite content (Vitamins)
  • BCH-GENE-SCBD-100269-8 Nopaline Synthase Gene Terminator | Agrobacterium tumefaciens (Agrobacterium)
  • BCH-GENE-SCBD-263474-2 1-deoxy-D-xylulose-5-phosphate synthase | Arabidopsis thaliana (Thale cress, Mouse-ear cress, Arabidopsis, ARATH)
    Protein coding sequence | Changes in quality and/or metabolite content (Vitamins)
  • BCH-GENE-SCBD-100366-6 CaMV Enhanced 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-100290-6 CaMV 35S terminator | Cauliflower mosaic virus (CaMV)
The modified cassava contains three gene cassettes: Pantoea ananas phytoene desaturase (crtI), Arabidopsis thaliana 1-deoxy-D-xylulose-5-phosphate synthase (dxs) and Escherichia coli neomycin phosphotransferase II (nptII).

The crtI coding sequence is under control of a potato (Solanum tuberosum) patatin-1 (B33) promoter and an Agrobacterium tumefaciens nopaline synthase (nos) terminator. An N-terminal Coriandrum sativum palmitoyl-[acyl-carrier-protein] 4-desaturase transit peptide was added to localize the translated protein to the plastids. Due to the nature of the promoter, transcription from this gene cassette is expected to be restricted to the tuber and root tissues of the plant.

The dxs sequence is under control of a B33 promoter and a nos terminator. Due to the nature of the promoter, transcription from this gene cassette is expected to be restricted to the tuber and root tissues of the plant.

The nptII sequence is under control of a Cauliflower mosaic virus enhanced promoter and terminator. Due to the constitutive nature and duplicated enhancers, transcription is expected to occur at high levels in all plant tissues.

LMO characteristics
  • Food
Detection method(s)