Data from: Macroevolution of leaf defenses and secondary metabolites across the genus Helianthus

Leaf defenses are widely recognized as key adaptations and drivers of
plant evolution. Across environmentally diverse habitats, the
macroevolution of leaf defenses can be predicted by the univariate
trade-off model, which predicts that defenses are functionally redundant
and thus trade off, and the resource availability hypothesis, which
predicts that defense investment is determined by inherent growth rate and
that higher defense will evolve in lower resource environments. Here, we
examined the evolution of leaf physical and chemical defenses and
secondary metabolites in relation to environmental characteristics and
leaf economic strategy across 28 species of Helianthus (the sunflowers).
Using a phylogenetic comparative approach, we found few evolutionary
trade-offs among defenses and no evidence for defense syndromes. We also
found that leaf defenses are strongly related to leaf economic strategy,
with higher defense in more resource-conservative species, although there
is little support for the evolution of higher defense in low-resource
habitats. A wide variety of physical and chemical defenses predict
resistance to different insect herbivores, fungal pathogens, and a
parasitic plant, suggesting that most sunflower defenses are not redundant
in function and that wild Helianthus represents a rich source of variation
for the improvement of crop sunflower.

叶片防御被广泛认为是植物进化的关键适应性特征与驱动因素。在环境多样的栖息地中，叶片防御的宏进化可通过单变量权衡模型（univariate trade-off model）与资源可获得性假说（resource availability hypothesis）进行预测：前者认为防御功能冗余，因此存在权衡关系；后者指出防御投入由内在生长速率决定，且低资源环境中会进化出更高水平的防御。在此，我们研究了向日葵属（Helianthus）28个物种的叶片物理防御、化学防御及次生代谢产物的进化，分析其与环境特征及叶片经济策略的关联。通过系统发育比较方法（phylogenetic comparative approach），我们发现防御间的进化权衡极少，且无证据支持防御综合征（defense syndromes）的存在。我们还发现，叶片防御与叶片经济策略密切相关——资源保守型物种的防御水平更高；但低资源栖息地中进化出更高防御的观点缺乏支持。多种物理与化学防御可预测对不同昆虫食草动物、真菌病原体及寄生植物的抗性，这表明向日葵的多数防御功能并非冗余，且野生向日葵属是作物向日葵改良的丰富变异来源。