Crop Genebank Knowledge Base

Transgenes in maize genetic resources

Contributors to this page: CIMMYT, Mexico (Suketoshi Taba), with inputs also received from IITA, Nigeria (Dominique Dumet), EMBRAPA, Brazil (Flavia Teixeira), USDA/ARS/NC7, ISU, USA (Mark Millard).

Transgene detection in seed banks is generally only important for those crops that are known to have undergone transgenic events, and where transgenic varieties were used in the area of collection or donation. However, transgenic maize has been detected inadvertently in many countries that officially have no transgenic maize.

List of current transgenes

The list below was compiled from AGBIOS.

• Glyphosate tolerant herbicide.
  • Representative event: NK603, GA21.
  • Gene: CP4 EPSPS
  • Region(s): Argentina, Brazil, Canada, EU, USA, others.

• Glufosinate ammonium herbicide tolerant.
  • Representative event: B16 (DLL25) and T14,T25.
  • Gene: PAT.
  • Region(s): Argentina, Brazil, Canada, EU, USA, others.

• Insect resistance (ECB).
  • Representative event: Mon810, 176.
  • Gene: Cry 1Ab gene from Bacillus thuringiensis spp.
  • Region(s): Argentina, Brazil, Canada, EU, USA, others.

• Insect resistance (CRW).
  • Representative event: Mon 863.
  • Gne: Cry3Bb1 from Bacillus thuringiensis spp.
  • Region(s): Argentina, Brazil, Canada, EU, USA, others.

• Insect (ECB) and herbicide tolerance (glufosinate ammonium).
  • Representative event: Bt11 (x4334CBR, x4734CBR).
  • Genes: Cry1Ab + PAT.
  • Region(s): Argentina, Brazil, Canada, EU, USA, others.

• Insect resistant and glufosinate ammonium herbicide tolerant.
  • Representative event: CBH-351.
  • Gene: Cry9C +PAT.
  • Region(s): USA.

• Lepidopteran insect and herbicide (glufocinate ammonium) resistant.
  • Representative event: DAS-06275-8, TC1507.
  • Genes: Cry1F +PAT.
  • Region(s): Brazil, Canada, EU, USA, others. 

Determination methods

All germplasm coming into the genebank should receive clearance by seed health laboratories, including the presence of any GMO. The following tests can be carried out for each specific type of potential transgene.

• Herbicide bioassay for the presence or absence of the herbicide resistance trait (NK603, GA21, PAT).
• ELISA assay for presence or absence and measurement of protein produced from the transgenes (Cry1Ab, Cry3Bb1, CP4ERSPS, Cry1F).
• PCR assay for presence or absence of 35 S and NOS- common promoter and terminator of inserted transgenic DNA (for all non regulated GMO genes).

More details about molecular protocols can be found at: CIMMYT's website (1.9MB)

Recording information during transgene detection

See also specific details about transgenes on this website.

The following information should be recorded for each step:

• Accession number (number).
• Introduction ID number (number).
• Collection name, pedigree (name, pedigree).
• Seed origin (field book, year, site, plot number).
• Sample size used and remaining (seed number, grams).
• Date tested (date).
• Traits tested for GMO presence (traits: gene, event).
• Results of the GMO detection (positive and negative).
• Recommendation (follow up, re-testing etc).
• Date released by the seed health department (date).
• Seed exchange policy (MLS, other to specify).

References and further reading

AGBIOS GM crop database [online]. Available from: http://cera-gmc.org/index.php?action=gm_crop_database. Date accessed: 15 September 2010.

CIMMYT. 2005. Laboratory Protocols: CIMMYT Applied Molecular Genetics Laboratory. Third Edition. Mexico, D.F.: CIMMYT.
ISBN: 9686923306

Position Statement on Genetically Modified Crop Varieties, CIMMYT. 

Scott MP, editor. 2009. Transgenic maize. Methods and protocols. Series Methods in Molecular Biology, Vol. 526. 200pp.

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