Abstract
Gene flow from transgenic crops can introduce novel traits into related species, but the ecological importance of this process is unknown. Here, we report the first empirical evidence that wild plants can benefit from a bacterial transgene under uncaged, natural conditions. Cultivated sunflower (Helianthus annuus) is known to hybridize frequently with wild sunflower (H. annuus) in the western and midwestern United States. We studied a crop-developed Bacillus thuringiensis (Bt) transgene, cry1Ac, in backcrossed wild sunflower populations. Lepidopteran damage on transgenic plants was strongly reduced relative to control plants at our two study sites, while damage by several weevil and fly species was unaffected. Our results suggest that reduced herbivory caused transgenic plants to produce an average of 55% more seeds per plant relative to nontransgenic controls at the field site in Nebraska. A similar but nonsignificant trend was seen at the site in Colorado (14% more seeds per plant). In a greenhouse experiment the transgene had no effect on fecundity, suggesting that it was not associated with a fitness cost. If Bt sunflowers are released commercially, we expect that Bt genes will spread to wild and weedy populations, limit damage from susceptible herbivores on these plants, and increase seed production when these herbivores are common. Corresponding Editor: C. R. Linder.
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Claims 6
Claim · model-written summary
Lepidopteran damage was strongly reduced on Bt transgenic wild sunflowers relative to control plants at two study sites.
- Taxon
- Helianthus annuus
Helianthus annuuse0 - Treatment
- Bacillus thuringiensis (Bt) transgene, cry1Ace1
- Interactor
- Lepidopterane2herbivore
- Outcome
- Lepidopteran damagee2
- Direction
- strongly reducede2
- Comparator
- control plantse2
- Setting
- two study sitese2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cultivated sunflower (Helianthus annuus) is known to hybridize frequently with wild sunflower (H. annuus) in the western and midwestern United States”
e1“We studied a crop-developed Bacillus thuringiensis (Bt) transgene, cry1Ac, in backcrossed wild sunflower populations”
e2“Lepidopteran damage on transgenic plants was strongly reduced relative to control plants at our two study sites, while damage by several weevil and fly species was unaffected”
Claim · model-written summary
Damage by several weevil and fly species was unaffected by the Bt transgene.
- Taxon
- Helianthus annuusHelianthus annuuse0
- Treatment
- Bacillus thuringiensis (Bt) transgene, cry1Ace1
- Interactor
- weevil and fly speciese2herbivore
- Outcome
- damage by several weevil and fly speciese2
- Direction
- unaffectede2
- Comparator
- control plantse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cultivated sunflower (Helianthus annuus) is known to hybridize frequently with wild sunflower (H. annuus) in the western and midwestern United States”
e1“We studied a crop-developed Bacillus thuringiensis (Bt) transgene, cry1Ac, in backcrossed wild sunflower populations”
e2“Lepidopteran damage on transgenic plants was strongly reduced relative to control plants at our two study sites, while damage by several weevil and fly species was unaffected”
Claim · model-written summary
Transgenic wild sunflowers produced an average of 55% more seeds per plant than nontransgenic controls at the Nebraska field site.
- Taxon
- Helianthus annuusHelianthus annuuse0
- Treatment
- transgenic plantse3
- Outcome
- seeds per plante3
- Direction
- moree3
- Value
- 55%e3
- Comparator
- nontransgenic controlse3
- Setting
- field site in Nebraskae3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cultivated sunflower (Helianthus annuus) is known to hybridize frequently with wild sunflower (H. annuus) in the western and midwestern United States”
e3“reduced herbivory caused transgenic plants to produce an average of 55% more seeds per plant relative to nontransgenic controls at the field site in Nebraska”
Claim · model-written summary
A similar but nonsignificant trend showed 14% more seeds per plant at the Colorado site.
- Taxon
- Helianthus annuusHelianthus annuuse0
- Treatment
- transgenic plantse3
- Outcome
- seeds per plante4
- Direction
- moree4
- Value
- 14%e4
- Setting
- site in Coloradoe4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cultivated sunflower (Helianthus annuus) is known to hybridize frequently with wild sunflower (H. annuus) in the western and midwestern United States”
e3“reduced herbivory caused transgenic plants to produce an average of 55% more seeds per plant relative to nontransgenic controls at the field site in Nebraska”
e4“A similar but nonsignificant trend was seen at the site in Colorado (14% more seeds per plant)”
Claim · model-written summary
In a greenhouse experiment the transgene had no effect on fecundity.
- Taxon
- Helianthus annuusHelianthus annuuse0
- Treatment
- transgenee5
- Outcome
- fecunditye5
- Direction
- no effecte5
- Setting
- greenhouse experimente5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cultivated sunflower (Helianthus annuus) is known to hybridize frequently with wild sunflower (H. annuus) in the western and midwestern United States”
e5“In a greenhouse experiment the transgene had no effect on fecundity, suggesting that it was not associated with a fitness cost”
Claim · model-written summary
The transgene is not associated with a fitness cost in wild sunflowers.
- Taxon
- Helianthus annuusHelianthus annuuse0
- Treatment
- transgenee5
- Outcome
- fitness coste5
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cultivated sunflower (Helianthus annuus) is known to hybridize frequently with wild sunflower (H. annuus) in the western and midwestern United States”
e5“In a greenhouse experiment the transgene had no effect on fecundity, suggesting that it was not associated with a fitness cost”
The same questions in other papers
Bacillus thuringiensis · pest · Helianthus annuus (common sunflower)Positive and negative results
1 in the opposite direction
- positive
transgenic · pest · Helianthus annuus (common sunflower)Positive and negative results
3 in the opposite direction
- positive
- positive
- positive
transgenic · yield · Helianthus annuus (common sunflower)Positive and negative results
4 in the opposite direction
- positive
- positive
- positive
1 paper more in this group
See all 5 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.