Testing Grain for Transgenic Traits

October 17, 2003  10(25):182-184

Joe Lauer, Corn Agronomist

I have been receiving calls regarding where grain can be tested for transgenic traits. More and more, the grain handling industry is treating transgenic grain as an identity preserved (IP) commodity. In order to segregate non-transgenic corn and soybean grain, grain elevator managers want to know whether an incoming load of grain has any transgenic grain mixed with non-transgenic grain. Ideally a qualitative transgenic detection test is needed that will provide reliable results in the time it takes a truckload of grain to move from the scale and probe to the dump pit. Perfecting such a test with statistically accurate results is a monumental task. The grain industry is not there yet, and can only provide specific tests for specific transgenic traits.

A number of tests methods are available for testing each having pros and cons associated with the methodology (Table 2). In general there are two scientific methods for detecting transgenic field crops. One method involves testing for specific protein that has been incorporated through biotechnology into a crop; the other is based on detection of DNA sequences inserted in the crop.

Farmer testing of transgenic traits can easily be accomplished using lateral flow strips (Table 3). Results with Lateral flow test strips are qualitative (yes or no for presence of transgenic trait). A number of companies produce these strips and they can be easily obtained (Table 4). Currently, there is no single, rapid or inexpensive test to verify whether a crop or crop sample is free of transgenic traits. Before purchasing a commercial test kit, it is best to know the specific crop and transgene to be tested.

Table 1. Wisconsin laboratories that conduct tests for transgenic traits (websites verified 15 October 2003).
Bioassays only Wisconsin Crop Improvement Association
1575 Linden Drive Madison, WI 53706  
(608) 262-1341
Fax: (608) 262-0210
www.wisc.edu/wcia/ 
All Methods BioDiagnostics, Inc.
507 Highland Drive
River Falls, Wisconsin 54022  
(715) 426-0246
Fax: (715) 426-0251
 www.biodiagnostics.net/index.html

 

Table 2. Methods to test for transgenic traits, their cost, duration ease of use and expected results.
Method Tests for Cost/Sample Duration Ease of Use Results
Bioassay
(For herbicide resistant traits)
Tolerance to chemical $10-12 5-7 days Moderate; requires familiarity with laboratory practices Quantitative measure for presence of herbicide resistance
ELISA
(Enzyme-Linked Immunosorption Assay)
Protein $75-100 a 2-4 days d Moderate; requires familiarity with laboratory practices and some specialized equipment Quantitative measurement of protein levels
Lateral Flow Strip Protein $8-10 b 10-20 minutes Little training and no sophisticated lab equipment required Qualitative measurement of presence or absence of target protein analyte
PCR
(Polymerase Chain Reaction)
DNA $200-600 ac 5-14 days d Difficult; requires specialized equipment and training Qualitative/semi-quantitative measurement of levels of target sequence
Southern Blot DNA $100-300 4-6 days Difficult; requires specialized training and equipment including radioactive materials Identifies specific DNA sequences
a Estimated cost of analysis performed by a commercial testing laboratory b Estimate cost of material to perform on-site analysis, excluding labor c Prices for PCR tests vary widely and depend on the nature of the test being performed (e.g., screening versus quantitative assessment) d Estimate of time required to have samples analyzed by a commercial testing laboratory. Sources: Gene Amberson and www.croplifeamerica.org/public/issues/biotech/detecta.pdf  (website verified 15 October 2003)

 

Table 3. Transgenic detection kits submitted to Grain Inspection, Packers and Stockyards Administration (GIPSA) of the Federal Grain Inspection Service by kit manufacturers. Kit performance as claimed by the manufacturer was verified by GIPSA.
Company Test Kit Part Number Event/Protein Analyte Test Sensitivity Test Format
Agdia, Inc. Roundup Ready® ImmunoStrip(TM) STX- 74000 Roundup Ready Protein CP4EPSPS 1 in 800
corn kernels
Lateral Flow Strip
EnviroLogix Inc. Cry9C 
ELISA Plate Kit, High Sensitivity Protocol
AP 008 StarLink/Cry9C 1 in 10,000 corn kernels Microtiter Well Plate Assay
EnviroLogix Inc. Cry9C 
ELISA Plate Kit, Rapid Protocol
AP 008 StarLink/Cry9C 1 in 2,400 corn kernels Microtiter Well Plate Assay
EnviroLogix Inc. QuickStix (TM) Strips for Cry9C (StarLink) AS 008 BG StarLink/Cry9C 1 in 800 corn kernels Lateral Flow Strip
EnviroLogix, Inc. QuickStix (TM) Strips for Roundup Ready® in Soybeans AS 010 BG  Roundup Ready® protein,CP4 EPSPS 1 in 1,000 soybeans  Lateral Flow Strip
EnviroLogix, Inc. QuickStix (TM) Strips for Roundup Ready® in Corn AS 010 BG  Roundup Ready® protein,CP4 EPSPS 1 in 200 corn kernels  Lateral Flow Strip
EnviroLogix Inc. QuickStix (TM) Kit for YieldGard® Rootworm Bulk Seed AS015BG Cry3Bb 1 in 200 corn kernels Lateral Flow Strip
Neogen Corporation  Agri-Screen CP4 Strip Test 8005 CP4 EPSPS protein of Roundup Ready soybean and Roundup Ready corn (NK603) 1 in 800 corn kernels 1 in 1,000 soybeans Lateral Flow Strip
Neogen Corporation Agri-Screen Qualitative Cry9C Test 8002a StarLink/Cry9C 1 in 800 corn kernels Microtiter Well Plate Assay
Neogen Corporation Agri-Screen Cry9C Strip Test 8003 StarLink/Cry9C 1 in 800 corn kernels Lateral Flow Strip
Strategic 
Diagnostics, Inc.
GMO TM Bt9 Maize Kit   7110030 StarLink/Cry9C 1 in 10,000 corn kernels Microtiter Well Plate Assay
Strategic 
Diagnostics Inc.
GMO Quick TM Bt9 Test Kit 7110020 StarLink/Cry9C 1 in 800 corn kernels Microtiter Well Plate Assay
Strategic 
Diagnostics Inc.
Trait  Bt9TM 7000034 StarLink/Cry9C 1 in 800 corn kernels1 Lateral Flow Strip
Strategic 
Diagnostics Inc.
Trait  Bt9TM 7000003 StarLink/Cry9C 1 in 800 corn kernels Lateral Flow Strip
Strategic 
Diagnostics Inc.
Trait  Bt9TM 7000012 StarLink/Cry9C 1 in 800 corn kernels Lateral Flow Strip
Strategic Diagnostics, Inc. TraitTM Cry3Bb Corn Grain Test kit 7000041 Cry3Bb (YieldGard Rootworm®) 1 in 800 corn kernels Lateral Flow Strip
Strategic
Diagnostics, Inc.
Trait RUR Bulk Soybeans 5-Minute Test Kit 7000014 Roundup Ready Soybeans/CP4 EPSPS 1 in 1,000 soybeans Lateral Flow Strip
Strategic
Diagnostics, Inc.
Trait RUR NK603 Corn Grain 5-Minute Test Kit 7000011 Roundup Ready Protein CP4 EPSPS 1 in 800 corn kernels Lateral Flow Strip
Strategic 
Diagnostics Inc.
TraitTM Bt1F
Corn Grain Test Kit
7000018 Cry1F
(HerculexTM)
1 in 600 corn kernels Lateral Flow Strip
1/   Sensitivity of 1 in 400 kernels requires a 10-minute development time. Sensitivity of 1 in 800 kernels requires a 20-minute development time.  Source: http://www.usda.gov/gipsa/  Click on "Tech Services/Support" (website verified 15 October 2003)/

 

Table 4.  Sources for Lateral flow test strips (websites verified 15 October 2003):
Envirologix, Inc.
500 Riverside Industrial Parkway
Portland, ME 04103  
(866) 408-4597
www.envirologix.com 
Strategic Diagnostic, Inc. (SDI)
111 Pencader Drive
Newark, Delaware 19702  
(800) 544-8881
www.sdix.com 
Neogen, Inc.
620 Lesher Place
Lansing MI 48912  
(800) 234-5333
www.neogen.com 
Agdia, Inc.
30380 County Road 6
Elkhart, IN 46514  
(800) 62-AGDIA
www.agdia.com/ 

University of Wisconsin, 1575 Linden Drive - Agronomy, Madison WI  53706    (608) 262-1390
If you would like to subscribe (or unsubscribe) to updates during the growing season, click here.
For a list of website updates, click here. Send comments about this website to Joe Lauer.
©  1994-2017 Board of Regents of the University of Wisconsin, Division of Cooperative Extension of UWEX.