Additive transgene expression and genetic introgression in multiple green-fluorescent protein transgenic crop × weed hybrid generations

Halfhill, Matthew D.; Millwood, Reginald J.; Weissinger, Arthur K.; Warwick, S. I.; Stewart, C. Neal

doi:10.1007/s00122-003-1397-7

Cited by 49 publications

(52 citation statements)

References 30 publications

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“…Canola is considered an annual, but secondary seed dormancy has now been confirmed [27]. Mature plants can overwinter as rosettes [17] and volunteers are routinely reported years after a canola harvest [21]. A substantial portion (1%-30%) of each crop is lost during harvest [27,28] and mature crops are frequently left unharvested because of unfavorable harvest conditions [29].…”

Section: Plant Materialsmentioning

confidence: 99%

Benefits of Transgenic Insect Resistance in Brassica Hybrids under Selection

et al. 2015

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Field trials of transgenic crops may result in unintentional transgene flow to compatible crop, native, and weedy species. Hybridization outside crop fields may create novel forms with potential negative outcomes for wild and weedy plant populations. We report here the outcome of large outdoor mesocosm studies with canola (Brassica napus), transgenic canola, a sexually compatible weed B. rapa, and their hybrids. Brassica rapa was hybridized with canola and canola carrying a transgene for herbivore resistance (Bt Cry1Ac) and grown in outdoor mesocosms under varying conditions of competition and insect herbivory. Treatment effects differed significantly among genotypes. Hybrids were larger than all other genotypes, and produced more seeds than the B. rapa parent. Under conditions of heavy herbivory, plants carrying the transgenic resistance were larger and produced more seeds than non-transgenic plants. Pollen derived gene flow from transgenic canola to B. rapa varied between years (5%-22%) and was not significantly OPEN ACCESSAgronomy 2015, 5 22 impacted by herbivory. These results confirm that canola-weed hybrids benefit from transgenic resistance and are aggressive competitors with congeneric crops and ruderals. Because some crop and crop-weed hybrids may be competitively superior, escapees may alter the composition and ecological functions of plant communities near transgenic crop fields.

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Section: Plant Materialsmentioning

confidence: 99%

Benefits of Transgenic Insect Resistance in Brassica Hybrids under Selection

et al. 2015

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“…In contrast, both weedy species, B. rapa and B. nigra, are highly selfincompatible and require pollinators for seed production. One thousand generalist pollinators (Musca domestica L.) (Rincon-Vitova Insectories, Ventura, CA, USA) were added to each mesocosm 5 days after selective treatments were applied (following Halfhill et al, 2003). Pollinators remained active throughout the course of the experiment in all mesocosms until harvest, at which time insect populations were terminated using electronic insect control (Flowtron Insect Killer, Malden, MA, USA).…”

Section: Jp Londo Et Almentioning

confidence: 99%

Changes in fitness-associated traits due to the stacking of transgenic glyphosate resistance and insect resistance in Brassica napus L.

et al. 2011

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Increasingly, genetically modified crops are being developed to express multiple 'stacked' traits for different types of transgenes, for example, herbicide resistance, insect resistance, crop quality and tolerance to environmental stresses. The release of crops that express multiple traits could result in ecological changes in weedy environments if feral crop plants or hybrids formed with compatible weeds results in more competitive plants outside of agriculture. To examine the effects of combining transgenes, we developed a stacked line of canola (Brassica napus L.) from a segregating F 2 population that expresses both transgenic glyphosate resistance (CP4 EPSPS) and lepidopteran insect resistance (Cry1Ac). Fitness-associated traits were evaluated between this stacked genotype and five other Brassica genotypes in constructed mesocosm plant communities exposed to insect herbivores (Plutella xylostella L.) or glyphosate-drift. Vegetative biomass, seed production and relative fecundity were all reduced in stacked trait plants when compared with non-transgenic plants in control treatments, indicating potential costs of expressing multiple transgenes without selection pressure. Although costs of the transgenes were offset by selective treatment, the stacked genotype continued to produce fewer seeds than either single transgenic line. However, the increase in fitness of the stacked genotype under selective pressure contributed to an increased number of seeds within the mesocosm community carrying unselected, hitchhiking transgenes. These results demonstrate that the stacking of these transgenes in canola results in fitness costs and benefits that are dependent on the type and strength of selection pressure, and could also contribute to changes in plant communities through hitchhiking of unselected traits.

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“…Several markers have been used in other crops to detect pollen-mediated gene flow in donor-receptor experiments including molecular markers based on quantitative PCR (Weekes et al, 2005(Weekes et al, , 2007Pla et al, 2006;Weber et al, 2007) or micro-satellite markers (Chaix et al, 2003;Dje et al, 2004;Isagi et al, 2004). Other techniques like green fluorescent protein (Halfhill et al, 2003) and blue aleurone seed color in wheat (Hanson et al, 2005) and triticale (Hills et al, 2007) ) (Kenaschuk and Rashid, 1994) and low ALA 'Solin' (o3% ALA) cultivars have been developed (Dribnenki et al, 2003). Two independently inherited genes, LuFA-D3A and LuFAD3B control the ALA trait in flax (Vrinten et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Pollen-mediated gene flow in flax (Linum usitatissimum L.): can genetically engineered and organic flax coexist?

et al. 2010

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Coexistence allows growers and consumers the choice of producing or purchasing conventional or organic crops with known standards for adventitious presence of genetically engineered (GE) seed. Flax (Linum usitatissimum L.) is multipurpose oilseed crop in which product diversity and utility could be enhanced for industrial, nutraceutical and pharmaceutical markets through genetic engineering. If GE flax were released commercially, pollen-mediated gene flow will determine in part whether GE flax could coexist without compromising other markets. ) to the low ALA trait. Seeds were harvested from the pollen recipient plots up to a distance of 50 m in eight directions from the pollen donor. High ALA seeds were identified using a thiobarbituric acid test and served as a marker for gene flow. Binomial distribution and power analysis were used to predict the minimum number of seeds statistically required to detect the frequency of gene flow at specific a (confidence interval) and power (1Àb) values. As a result of the low frequency of gene flow, approximately 4 million seeds were screened to derive accurate quantification. Frequency of gene flow was highest near the source: averaging 0.0185 at 0.1 m but declined rapidly with distance, 0.0013 and 0.00003 at 3 and 35 m, respectively. Gene flow was reduced to 50% (O 50 ) and 90% (O 90 ) between 0.85 to 2.64 m, and 5.68 to 17.56 m, respectively. No gene flow was detected at any site or year 435 m distance from the pollen source, suggesting that frequency of gene flow was p0.00003 (P ¼ 0.95). Although it is not possible to eliminate all adventitious presence caused by pollen-mediated gene flow, through harvest blending and the use of buffer zones between GE and conventional flax fields, it could be minimized. Managing other sources of adventitious presence including seed mixing and volunteer populations may be more problematic.

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Additive transgene expression and genetic introgression in multiple green-fluorescent protein transgenic crop × weed hybrid generations

Cited by 49 publications

References 30 publications

Benefits of Transgenic Insect Resistance in Brassica Hybrids under Selection

Benefits of Transgenic Insect Resistance in Brassica Hybrids under Selection

Changes in fitness-associated traits due to the stacking of transgenic glyphosate resistance and insect resistance in Brassica napus L.

Pollen-mediated gene flow in flax (Linum usitatissimum L.): can genetically engineered and organic flax coexist?

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