Progressive introgression between Brassica napus (oilseed rape) and B. rapa

Hansen, Lise Bach; Siegismund, Hans R.; Jørgensen, Rikke Bagger

doi:10.1038/sj.hdy.6800335

Cited by 69 publications

(64 citation statements)

References 19 publications

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“…Although we detected no transgene introgression into B. rapa or B. juncea in the present investigation, such introgression may occur in areas such as roadsides where plants of these species grow side by side, spontaneously or artificially, and hybridization or introgression has been reported to occur between B. napus and these species under natural conditions (Bing et al, 1996;Hansen et al, 2003;Jørgensen et al, 1996;Warwick et al, 2004). The fitness of the resulting hybrids or backcrossed plants is typically reduced in early generations; the F 1 and BC 1 generations usually exhibit reduced pollen fertility and seed production (Brown and Brown, 1996;Frello et al, 1995;Mikkelsen et al, 1996b).…”

Section: Resultscontrasting

confidence: 64%

Monitoring the escape of transgenic oilseed rape around Japanese ports and roadsides

Saji

Nakajima

Aono

et al. 2005

Environ. Biosafety Res.

100

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An investigation was carried out to monitor the escape and spread of oilseed rape (Brassica napus) transgenic plants and the introgression of transgenes to its closely related feral species in Japan. We screened a total of about 7500 feral B. napus, 300 B. rapa, and 5800 B. juncea seedlings from maternal plants in 143 locations at several ports, roadsides, and riverbanks. The presence of glufosinate-resistance or glyphosate-resistance transgenes in these seedlings was confirmed by means of herbicide treatments and also immunochemical and DNA analyses. B. napus plants with herbicide-resistant transgenic seeds were found at five of six major ports and along two of four sampled roadsides in the Kanto District. Transgenic oilseed rape plants have not been commercially cultivated in Japan, suggesting that the transgenes would probably have come from imported transgenic seeds that were spilled during transportation to oilseed processing facilities. No transgenes were detected in seeds collected from B. napus plants growing along riverbanks in the Kanto District or in seeds from closely related species (B. rapa and B. juncea). To our knowledge, this is the first published example of feral, transgenic populations occurring in a nation where the transgenic crop has not been cultivated commercially.

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Section: Resultscontrasting

confidence: 64%

Monitoring the escape of transgenic oilseed rape around Japanese ports and roadsides

Saji

Nakajima

Aono

et al. 2005

Environ. Biosafety Res.

100

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“…The higher photosynthetic capability suggests that F 1 hybrids may have enhanced vegetative vigor compared to their parents, and may present a larger potential for transgene spread than formerly expected. The compounded fitness estimate suggests a high seed set per F 1 plant, and spontaneous introgression of genes from B. napus × B. rapa hybrids to wild species has been reported (Hansen et al, 2001;Hansen et al, 2003). BC 1 hybrids form the next step of transgene introgression into wild species, but our results suggest that the vegetative vigor of the BC 1 plants is limited.…”

Section: Resultscontrasting

confidence: 52%

“…In addition, B. napus can hybridize with at least eight related species, B. rapa being the most likely hybridization partner. A high degree of spontaneous hybridization between oilseed rape and the weedy and wild relative B. rapa can occur under field conditions (Jørgensen and Andersen, 1994), and there is a well documented possibility of gene exchange between these species (Hansen et al, 2001;Hansen et al, 2003). We used two transgenic B. napus lines to produce the first hybrid generation (F 1 ) and the first backcross generation (BC 1 ) with two populations of B. rapa.…”

Section: Introductionmentioning

confidence: 99%

Transgene expression and fitness of hybrids between GM oilseed rape andBrassica rapa

Ammitzbøll

Mikkelsen

Jørgensen

2005

Environ. Biosafety Res.

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Oilseed rape (Brassica napus) is sexually compatible with its wild and weedy relative B. rapa, and introgression of genes from B. napus has been found to occur over a few generations. We simulated the early stages of transgene escape by producing F 1 hybrids and the first backcross generation between two lines of transgenic B. napus and two populations of weedy B. rapa. Transgene expression and the fitness of the hybrids were examined under different environmental conditions. Expression of the transgenes was analyzed at the mRNA level by quantitative PCR and found to be stable in the hybrids, regardless of the genetic background and the environment, and equal to the level of transcription in the parental B. napus lines. Vigor of the hybrids was measured as the photosynthetic capability; pollen viability and seed set per silique. Photosynthetic capability of first generation hybrids was found to be at the same level, or higher, than that of the parental species, whereas the reproductive fitness was significantly lower. The first backcross generation had a significantly lower photosynthetic capability and reproductive fitness compared to the parental species. This is the first study that examines transgene expression at the mRNA level in transgenic hybrids of B. napus of different genetic background exposed to different environmental conditions. The data presented clarify important details of the overall risk assessment of growing transgenic oilseed rape.

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“…This is not surprising, as B. rapa (AA genome, 2n 020 chromosomes) is one of the progenitor species of B. napus (AACC genome, 2n 038 chromosomes). Spontaneous hybridization and introgression between weedy B. rapa and B. napus was reported in Danish studies (Jørgensen and Andersen 1994;Jørgensen et al 1996;Landbo et al 1996;Hansen et al 2001Hansen et al , 2003,United States field studies (Halfhill et al 2002, and United Kingdom studies (Wilkinson et al 2003); and between cultivated lines of B. rapa and B. napus in field experiments in Canada (Bing et al 1996b). Based on the distribution of herbarium specimens, weedy B. rapa has a limited distribution as an agricultural and/or ruderal weed in B. napus growing areas in Quebec ).…”

Section: Female Parent)male Parent Citationmentioning

confidence: 99%

The Biology of Canadian Weeds. 137. Brassica napus L. and B. rapa L.

Gulden¹,

Warwick²,

Thomas³

2008

Can. J. Plant Sci.

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. 2008. The Biology of Canadian Weeds. 137. Brassica napus L. and B. rapa. Can. J. Plan Sci. 88: 951Á996. Brassica napus and B. rapa are native to Eurasia. In Canada, these species are commonly referred to as volunteer canola, while feral populations of B. rapa are referred to as birdrape. Brassica napus and B. rapa have been grown commercially for their seed oil content in western Canada since the middle of the last century and volunteer populations are common in fields. Escaped populations of both species are also found along roadways, railways and in waste areas; however, only B. rapa is known to have naturalized, self-sustaining feral populations in these habitats in eastern Canada. Despite these escaped and feral populations, B. napus and B. rapa are mainly a concern in agricultural fields where their combined relative abundance has increased over the past few decades. In the mid 1990s, herbicideresistant genotypes of B. napus were released for commercial production. Herbicide-resistance and the stacking of genes in volunteer populations conferring resistance to multiple herbicides have contributed to increased difficulties in controlling volunteer B. napus in some crops. However, yield loss resulting from volunteer populations is not well documented in Canada.Key words: Brassica napus, Brassica rapa, herbicide resistance, transgene escape, volunteer canola, weed biology Gulden, R. H., Warwick, S. I. et Thomas, A. G. 2008. La biologie des mauvaises herbes au Canada. 137. Brassica napus L. et B. rapa L. Can. J. Plant Sci. 88: 951Á996. Brassica napus et B. rapa sont des plantes originaires d'Eurasie. Au Canada, on les de´signe souvent sous l'expression « canola spontane´», tandis que les peuplements sauvages de B. rapa sont appele´s « navette ». Dans l'Ouest canadien, Brassica napus et B. rapa sont cultive´s commercialement pour l'huile que renferment leurs graines depuis le milieu du sie`cle dernier et les repousses spontane´es sont devenues monnaie courante dans les champs. On observe des peuplements des deux espe`ces le long des routes et des voies ferre´es ainsi que dans les terrains vagues, cependant on sait que seule B. rapa s'est acclimate´e pour donner des populations sauvages et stables dans les meˆmes habitats, dans l'est du pays. Malgre´cela, B. napus et B. rapa demeurent surtout pre´occupants dans les cultures, oul eur abondance relative, une fois combine´s, s'est accrue au cours des dernie`res de´cennies. Au milieu des anne´e 1990, des ge´notypes de B. napus re´sistants aux herbicides ont e´te´homologue´s pour la culture commerciale. Cette re´sistance et l'accumulation des ge`nes qui la codent dans les peuplements spontane´s ont concouru a`compliquer la lutte contre les repousses de B. napus dans certaines cultures. Quoi qu'il en soit, les pertes de rendement qui en re´sultent sont mal e´taye´es au Canada.

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Progressive introgression between Brassica napus (oilseed rape) and B. rapa

Cited by 69 publications

References 19 publications

Monitoring the escape of transgenic oilseed rape around Japanese ports and roadsides

Monitoring the escape of transgenic oilseed rape around Japanese ports and roadsides

Transgene expression and fitness of hybrids between GM oilseed rape andBrassica rapa

The Biology of Canadian Weeds. 137. Brassica napus L. and B. rapa L.

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