Assembled database of wild-crop comparisons from Domestication impacts on plant-herbivore interactions: a meta-analysis

For millennia, humans have imposed strong selection on domesticated crops, resulting in drastically altered crop phenotypes compared with wild ancestors. Crop yields have increased, but a long-held hypothesis is that domestication has also unintentionally decreased plant defences against herbivores. To test this hypothesis, we conducted a phylogenetically controlled meta-analysis comparing insect herbivore resistance and putative plant defence traits between crops and their wild relatives. Our database included 2098 comparisons made across 73 crops in 89 studies. We found that domestication consistently reduced plant resistance to herbivores, although the magnitude of the effects varied across plant organs and depending on how resistance was measured. However, domestication had no consistent effects on the specific plant defence traits underlying resistance, including secondary metabolites and physical feeding barriers. The values of these traits sometimes increased and sometimes decreased during domestication. Consistent negative effects of domestication were observed only when defence traits were measured in reproductive organs or in the plant organ that was harvested. These results highlight the complexity of evolution under domestication and the need for an improved theoretical understanding of the mechanisms through which agronomic selection can influence the species interactions that impact both the yield and sustainability of our food systems.This article is part of the themed issue 'Human influences on evolution, and the ecological and societal consequences'.

数千年来，人类对驯化作物施加了强烈的选择压力，使得驯化作物的表型相较于野生祖先发生了剧烈改变。尽管作物产量得以提升，但长期以来存在一个假说：驯化过程也会在无意间降低植物对植食性昆虫的防御能力。为验证该假说，我们开展了一项系统发育控制元分析，对比了作物与其野生近缘种之间的昆虫植食性抗性以及推定的植物防御性状。本研究的数据库涵盖了89项研究中针对73种作物的2098组对比数据。研究发现，驯化作用整体上会降低植物对植食性昆虫的抗性，不过该效应的强弱因植物器官类型以及抗性测定方式的不同而存在差异。然而，驯化对抗性背后的特定植物防御性状并未产生一致的影响，这些性状包括次生代谢物与物理取食屏障。在驯化过程中，这些性状的表现水平有时会上升，有时则会下降。仅当在生殖器官或人类收获的植物器官中测定防御性状时，才能观察到驯化带来的显著负向效应。上述结果凸显了驯化演化过程的复杂性，也表明我们需要进一步完善理论认知，阐明农艺选择如何影响那些同时影响作物产量与食物系统可持续性的物种互作机制。本文属于专题特刊“人类对演化的影响及其生态与社会后果”的组成部分。