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Bt-transgenic oilseed rape hybridization with its weedy relative, Brassica rapa

Published online by Cambridge University Press:  15 October 2002

Matthew D. Halfhill
University of North Carolina at Greensboro, Department of Biology, 312 Eberhart Bldg. Greensboro, NC 27402, USA
Reginald J. Millwood
University of North Carolina at Greensboro, Department of Biology, 312 Eberhart Bldg. Greensboro, NC 27402, USA
Paul L. Raymer
University of Georgia, Georgia Experiment Station, Griffin, GA 20223, USA
C. Neal Stewart Jr.
Dept. of Plant Science and Landscape Systems, University of Tennessee, Knoxville, TN 37996, USA


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The movement of transgenes from crops to weeds and the resulting consequences are concerns of modern agriculture. The possible generation of “superweeds” from the escape of fitness-enhancing transgenes into wild populations is a risk that is often discussed, but rarely studied. Oilseed rape, Brassica napus (L.), is a crop with sexually compatible weedy relatives, such as birdseed rape (Brassica rapa (L.)). Hybridization of this crop with weedy relatives is an extant risk and an excellent interspecific gene flow model system. In laboratory crosses, T3 lines of seven independent transformation events of Bacillus thuringiensis (Bt) oilseed rape were hybridized with two weedy accessions of B. rapa. Transgenic hybrids were generated from six of these oilseed rape lines, and the hybrids exhibited an intermediate morphology between the parental species. The Bt transgene was present in the hybrids, and the protein was synthesized at similar levels to the corresponding independent oilseed rape lines. Insect bioassays were performed and confirmed that the hybrid material was insecticidal. The hybrids were backcrossed with the weedy parent, and only half the oilseed rape lines were able to produce transgenic backcrosses. After two backcrosses, the ploidy level and morphology of the resultant plants were indistinguishable from B. rapa. Hybridization was monitored under field conditions (Tifton, GA, USA) with four independent lines of Bt oilseed rape with a crop to wild relative ratio of 1200:1. When B. rapa was used as the female parent, hybridization frequency varied among oilseed rape lines and ranged from 16.9% to 0.7%.

Research Article
© ISBR, EDP Sciences, 2002


Chevre, AM, Eber, F, Baranger, A, Renard, M (1997) Gene flow from transgenic crops. Nature 389: 924 CrossRef
Chevre, A, Eber, F, Darmency, H, Fleury, A, Picault, H, Letanneur, J, Renard, M (2000) Assessment of interspecific hybridization between transgenic oilseed rape and wild radish under normal agronomic conditions. Theor. Appl. Genet. 100: 1233-1239
Cho, HS, Cao, J, Ren, JP, Earle, ED (2001) Control of Lepidopteran insect pests in transgenic Chinese cabbage (Brassica rapa ssp. pekinensis) transformed with a synthetic Bacillus thuringiensis Cry1C gene. Plant Cell Rep. 20: 1-7 CrossRef
Darmency, H, Lefol, E, Fleury, A (1998) Spontaneous hybridizations between oilseed rape and wild radish. Mol. Ecol. 7: 1467-1473 CrossRef
Eber, F, Chevre, AM, Baranger, A, Vallee, P, Tanguy, X, Renard, M (1994) Spontaneous hybridization between a male-sterile oilseed rape and two weeds. Theor. Appl. Genet. 88: 362-368
Galbraith, DW, Harkins, KR, Maddox, JM, Ayres, NM, Sharma, DP, Firoozabady, E (1983) Rapid flow cytometric analysis of the cell cycle in intact plant tissues. Science 220: 1049-1051 CrossRef
Halfhill MD, Richards HA, Mabon SA, Stewart CN Jr. (2001) Expression of Bt transgenes in Brassica napus and hybridization with Brassica rapa. Theor. Appl. Genet. 103: 659-667
Harper, BK, Mabon, SA, Leffel, SM, Halfhill, MD, Richards, HA, Moyer, KA, Stewart, CN Jr. (1999) Green fluorescent protein as a marker for expression of a second gene in transgenic plants. Nat. Biotechnol. 17: 1125-1129
Hauser, T, Shaw, RG, Ostergard, H (1998a) Fitness of F1 hybrids between weedy Brassica rapa and oilseed rape (B. napus). Heredity 81: 429-435 CrossRef
Hauser, T, Jorgensen, R, Ostergard, H (1998b) Fitness of backcross and F2 hybrids between weedy Brassica rapa and oilseed rape (B. napus). Heredity 81: 436-443 CrossRef
Holm L, Doll J, Holm E, Pancho J, Herberger J (1997) Brassica campestris L. In World Weeds: Natural Histories and Distribution. John Wiley & Sons, Inc., New York, pp 117-124
Jorgensen, RB, Andersen, B (1994) Spontaneous hybridization between oilseed rape (Brassica napus) and weedy B. campestris (Brassicaceae): a risk of growing gentically modified oilseed rape. Am. J. Bot. 81: 1620-1626 CrossRef
Lefol, E, Danielou, V, Darmency, H (1996) Predicting hybridization between transgenic oilseed rape and wild mustard. Field Crops Res. 45: 153-161 CrossRef
Metz, PLJ, Jacobsen, E, Nap, JP, Pereira, A, Stiekema, WJ (1997) The impact of biosafety of the phosphinothricin-tolerance transgene in inter-specific B. rapa $\times$ B. napus hybrids and their successive backcrosses. Theor. Appl. Genet. 95: 442-450 CrossRef
Mikkelsen, TR, Andersen, B, Jorgensen, RB (1996) The risk of crop transgene spread. Nature 380: 31 CrossRef
Murashige, T, Skoog, F (1962) A revised medium for rapid growth and bioassays with tobacco tissue cultures. Physiol. Plant. 15: 476-497 CrossRef
Paul, EM, Thompson, C, Dunwell, JM (1995) Gene dispersal from genetically modified oil seed rape in the field. Euphytica 81: 283-289 CrossRef
Pratt LH, McCurdy DW, Shimazaki Y, Cordonnier MM (1986) Immunodetection of phytochrome: Immunocytochemistry, immunoblotting, and immunoquantitation. In Linskens HF, Jackson JF, eds, Modern Methods of Plant Analysis. Springer-Verlag, New York, pp 50-74
Ramachandran, S, Buntin, GD, All, JN, Raymer, PL, Stewart, CN Jr. (2000) Intraspecific competition of an insect-resistant transgenic canola in seed mixtures. Agron. J. 92: 368-374 CrossRef
Raybould, AF, Gray, AJ (1993) Genetically modified crops and hybridization with wild relatives: a UK perspective. J. Appl. Ecol. 30: 199-219 CrossRef
Rieger, MA, Preston, C, Powles, SB (1999) Risks of gene flow from transgenic herbicide-resistant oilseed rape (Brassica napus) to weedy relatives in southern Australian cropping systems. Aust. J. Agric. Res. 50: 115-128 CrossRef
Snow AA, Andersen B, Jorgensen RB (1999) Costs of transgenic herbicide resistance introgressed from Brassica napus into weedy B. rapa. Mol. Ecol. 8: 605-615
Stewart, CN Jr., Adang, MJ, All, JN, Boerma, HR, Cardineau, G, Tucker, D, Parrott, WA (1996a) Genetic transformation, recovery, and characterization of fertile soybean transgenic for a synthetic Bacillus thuringiensis cryIAc gene. Plant Physiol. 112: 121-129 CrossRef
Stewart, CN Jr., Adang, MJ, All, JN, Raymer, PL, Ramachandran, S, Parrott, WA (1996b) Insect control and dosage effects in transgenic oilseed rape, Brassica napus L. (Brassicaceae) containing a synthetic Bacillus thuringiensis cryIAc gene. Plant Physiol. 112: 115-120 CrossRef
Stewart, CN Jr., All, JN, Raymer, PL, Ramachandran, S (1997) Increased fitness of transgenic insecticidal rapeseed under insect selection pressure. Mol. Ecol. 6: 773-779 CrossRef
Tomiuk J, Hauser TP, Bagger-Jorgensen R (2000) A- or C- chromosomes, does it matter for the transfer of transgenes from Brassica napus. Theor. Appl. Genet. 100: 750-754
Warwick, SI, Beckie, HJ, Small, E (1999) Transgenic crops: new weed problems for Canada? Phytoprotection 80: 71-84 CrossRef
Xiang, Y, Wong, WKR, Ma, MC, Wong, RSC (2000) Agrobacterium-mediated transformation of Brassica campestris ssp. Parachinensis with synthetic Bacillus thuringiensis cry1Ab and cry1Ac genes. Plant Cell Rep. 19: 251-256 CrossRef