By organism › Green plants › Apocynaceae › Asclepias

Associationobservedoriginal resultpositivemeasured

Claim · model-written summary

An N,S heterocycle in substituted cardenolides restored toxicity against coevolved natural enemies.

Taxon: Asclepias speciesAsclepiast0
Interactor: monarch butterflyDanaus plexippuse0herbivore
Outcome: toxicity against coevolved natural enemiese0
Direction: restorese0
Qualifier: nitrogen–sulfur (N,S) heterocyclee0

Verbatim

e0
“We identify the addition of a nitrogen–sulfur (N,S) heterocycle in highly substituted cardenolides as a major structural innovation that restores toxicity against coevolved natural enemies, such as the monarch butterfly.”
✓ located verbatim in the source · abstract, characters 551–771

t0
“59 Asclepias species examined here”
✓ located verbatim in the source · abstract, characters 1585–1619

Title

Structural innovation in the evolution of plant chemical defense

Paola Rubiano-Buitrago; Amy P. Hastings; Masaaki Uematsu; et al. Proceedings of the National Academy of Sciences 2026. doi:10.1073/pnas.2535853123

Other claims from this paper (10)

Mechanism The authors proposed that scaffold rigidification and extra binding interactions enhance affinity despite resistance.
Observation Uscharin ranked among the most complex cardenolides.
Observation Labriformin ranked among the most complex cardenolides.
Observation Uscharin was inferred ancestral with repeated losses.
Observation Labriformin evolved independently multiple times.
Observation N,S cardenolides occurred in over 75% of 59 Asclepias species.
Association Species producing N,S cardenolides had greater cardenolide abundance.
Association Species producing N,S cardenolides had greater cardenolide richness.
Association Species producing N,S cardenolides had greater metabolomic space.
Association Species producing N,S cardenolides had greater toxicity against adapted organisms.

Mechanismauthor interpretationoriginal resultsimulated

Claim · model-written summary

The authors proposed that scaffold rigidification and extra binding interactions enhance affinity despite resistance.

Taxon: Asclepias speciesAsclepiast0
Outcome: binding affinitye0
Qualifier: rigidifying the cardenolide scaffold and creating additional nonelectrostatic interactions within the Na + /K + -ATPase binding pockete0

Verbatim

e0
“This toxicity is likely achieved by rigidifying the cardenolide scaffold and creating additional nonelectrostatic interactions within the Na + /K + -ATPase binding pocket, thereby enhancing binding affinity despite target-site resistance.”
✓ located verbatim in the source · abstract, characters 772–1010

t0
“59 Asclepias species examined here”
✓ located verbatim in the source · abstract, characters 1585–1619

Title

Structural innovation in the evolution of plant chemical defense

Paola Rubiano-Buitrago; Amy P. Hastings; Masaaki Uematsu; et al. Proceedings of the National Academy of Sciences 2026. doi:10.1073/pnas.2535853123

Other claims from this paper (10)

Association An N,S heterocycle in substituted cardenolides restored toxicity against coevolved natural enemies.
Observation Uscharin ranked among the most complex cardenolides.
Observation Labriformin ranked among the most complex cardenolides.
Observation Uscharin was inferred ancestral with repeated losses.
Observation Labriformin evolved independently multiple times.
Observation N,S cardenolides occurred in over 75% of 59 Asclepias species.
Association Species producing N,S cardenolides had greater cardenolide abundance.
Association Species producing N,S cardenolides had greater cardenolide richness.
Association Species producing N,S cardenolides had greater metabolomic space.
Association Species producing N,S cardenolides had greater toxicity against adapted organisms.

Observationobservedoriginal resultmeasured

Claim · model-written summary

Uscharin ranked among the most complex cardenolides.

Taxon: Asclepias speciesAsclepiast0
Outcome: uscharine0
Direction: most complexe0

Verbatim

e0
“Two biosynthetically distinct N,S-cardenolides, uscharin and labriformin, rank among the most complex structures in this chemical class”
✓ located verbatim in the source · abstract, characters 1011–1146

t0
“59 Asclepias species examined here”
✓ located verbatim in the source · abstract, characters 1585–1619

Title

Structural innovation in the evolution of plant chemical defense

Paola Rubiano-Buitrago; Amy P. Hastings; Masaaki Uematsu; et al. Proceedings of the National Academy of Sciences 2026. doi:10.1073/pnas.2535853123

Other claims from this paper (10)

Observationobservedoriginal resultmeasured

Claim · model-written summary

Labriformin ranked among the most complex cardenolides.

Taxon: Asclepias speciesAsclepiast0
Outcome: labriformine0
Direction: most complexe0

Verbatim

e0
“Two biosynthetically distinct N,S-cardenolides, uscharin and labriformin, rank among the most complex structures in this chemical class”
✓ located verbatim in the source · abstract, characters 1011–1146

t0
“59 Asclepias species examined here”
✓ located verbatim in the source · abstract, characters 1585–1619

Title

Structural innovation in the evolution of plant chemical defense

Paola Rubiano-Buitrago; Amy P. Hastings; Masaaki Uematsu; et al. Proceedings of the National Academy of Sciences 2026. doi:10.1073/pnas.2535853123

Other claims from this paper (10)

Association An N,S heterocycle in substituted cardenolides restored toxicity against coevolved natural enemies.
Mechanism The authors proposed that scaffold rigidification and extra binding interactions enhance affinity despite resistance.
Observation Uscharin ranked among the most complex cardenolides.
Observation Uscharin was inferred ancestral with repeated losses.
Observation Labriformin evolved independently multiple times.
Observation N,S cardenolides occurred in over 75% of 59 Asclepias species.
Association Species producing N,S cardenolides had greater cardenolide abundance.
Association Species producing N,S cardenolides had greater cardenolide richness.
Association Species producing N,S cardenolides had greater metabolomic space.
Association Species producing N,S cardenolides had greater toxicity against adapted organisms.

Observationobservedoriginal resultmeasured

Claim · model-written summary

Uscharin was inferred ancestral with repeated losses.

Taxon: Asclepias speciesAsclepiast0
Outcome: ancestral character state with repeated lossese0
Qualifier: uscharine0

Not reportedDirection

Verbatim

e0
“uscharin represents an ancestral character state with repeated losses”
✓ located verbatim in the source · abstract, characters 1195–1264

t0
“59 Asclepias species examined here”
✓ located verbatim in the source · abstract, characters 1585–1619

Title

Structural innovation in the evolution of plant chemical defense

Paola Rubiano-Buitrago; Amy P. Hastings; Masaaki Uematsu; et al. Proceedings of the National Academy of Sciences 2026. doi:10.1073/pnas.2535853123

Other claims from this paper (10)

Observationobservedoriginal resultmeasured

Claim · model-written summary

Labriformin evolved independently multiple times.

Taxon: Asclepias speciesAsclepiast0
Outcome: independently evolved multiple timese0
Qualifier: labriformine0

Not reportedDirection

Verbatim

e0
“labriformin has independently evolved multiple times in later-diverging lineages.”
✓ located verbatim in the source · abstract, characters 1274–1355

t0
“59 Asclepias species examined here”
✓ located verbatim in the source · abstract, characters 1585–1619

Title

Structural innovation in the evolution of plant chemical defense

Paola Rubiano-Buitrago; Amy P. Hastings; Masaaki Uematsu; et al. Proceedings of the National Academy of Sciences 2026. doi:10.1073/pnas.2535853123

Other claims from this paper (10)

Observationobservedoriginal resultmeasured

Claim · model-written summary

N,S cardenolides occurred in over 75% of 59 Asclepias species.

Taxon: Asclepias speciesAsclepiase0
Outcome: N,S-cardenolides occure0
Value: over 75%e0

Verbatim

e0
“N,S-cardenolides occur in over 75% of the 59 Asclepias species examined here”
✓ located verbatim in the source · abstract, characters 1543–1619

Title

Structural innovation in the evolution of plant chemical defense

Paola Rubiano-Buitrago; Amy P. Hastings; Masaaki Uematsu; et al. Proceedings of the National Academy of Sciences 2026. doi:10.1073/pnas.2535853123

Other claims from this paper (10)

Association An N,S heterocycle in substituted cardenolides restored toxicity against coevolved natural enemies.
Mechanism The authors proposed that scaffold rigidification and extra binding interactions enhance affinity despite resistance.
Observation Uscharin ranked among the most complex cardenolides.
Observation Labriformin ranked among the most complex cardenolides.
Observation Uscharin was inferred ancestral with repeated losses.
Observation Labriformin evolved independently multiple times.
Association Species producing N,S cardenolides had greater cardenolide abundance.
Association Species producing N,S cardenolides had greater cardenolide richness.
Association Species producing N,S cardenolides had greater metabolomic space.
Association Species producing N,S cardenolides had greater toxicity against adapted organisms.

Associationobservedoriginal resultmeasured

Claim · model-written summary

Warmer mean spring temperatures generally advanced phenology of milkweed species.

Taxon: Asclepias spp.Asclepiase0
Treatment: Warmer mean spring temperaturese1
Outcome: phenologye1
Direction: advancede1

Verbatim

e0
“in five species of milkweeds ( Asclepias spp.)”
✓ located verbatim in the source · abstract, characters 260–306

e1
“Warmer mean spring temperatures generally advanced phenology, while wetter rain‐years generally delayed phenology”
✓ located verbatim in the source · abstract, characters 738–851

Title

Temperature and precipitation explain species‐specific phenological patterns in five native California milkweed species ( Asclepias spp.)

Dylan J. MacArthur‐Waltz; Dylan S. Sommer; Prabhjot Singh; et al. Journal of Ecology 2025. doi:10.1111/1365-2745.70185

Other claims from this paper (6)

Associationobservedoriginal resultmeasured

Claim · model-written summary

Wetter rain-years generally delayed phenology of milkweed species.

Taxon: Asclepias spp.Asclepiase0
Treatment: wetter rain‐yearse1
Outcome: phenologye1
Direction: delayede1

Verbatim

e0
“in five species of milkweeds ( Asclepias spp.)”
✓ located verbatim in the source · abstract, characters 260–306

e1
“Warmer mean spring temperatures generally advanced phenology, while wetter rain‐years generally delayed phenology”
✓ located verbatim in the source · abstract, characters 738–851

Title

Temperature and precipitation explain species‐specific phenological patterns in five native California milkweed species ( Asclepias spp.)

Dylan J. MacArthur‐Waltz; Dylan S. Sommer; Prabhjot Singh; et al. Journal of Ecology 2025. doi:10.1111/1365-2745.70185

Other claims from this paper (6)

Associationobservedoriginal resultmeasured

Claim · model-written summary

Spring mean temperature advanced phenology by 2.56 ± 1.71 days per °C across milkweed species and phenophases.

Taxon: Asclepias spp.Asclepiase0
Treatment: spring mean temperaturee2
Outcome: phenologye2
Direction: advancede2
Value: 2.56 ± 1.71 days × spring temp°C −1e2

Verbatim

e0
“in five species of milkweeds ( Asclepias spp.)”
✓ located verbatim in the source · abstract, characters 260–306

e2
“spring mean temperature advanced phenology by 2.56 ± 1.71 days × spring temp°C −1 (mean ± SD)”
✓ located verbatim in the source · abstract, characters 908–1001

Title

Temperature and precipitation explain species‐specific phenological patterns in five native California milkweed species ( Asclepias spp.)

Dylan J. MacArthur‐Waltz; Dylan S. Sommer; Prabhjot Singh; et al. Journal of Ecology 2025. doi:10.1111/1365-2745.70185

Other claims from this paper (6)

Asclepias 201 claims

201 claims