Abstract：
Plant domestication often alters plant traits, including chemical and physical defenses against herbivores. In squash, domestication leads to reduced levels of cucurbitacins and leaf trichomes, influencing interactions with insects. However, the impact of domestication on inducible defenses in squash remains poorly understood. Here, we investigated the chemical and physical defensive traits of wild and domesticated squash (Cucurbita argyrosperma), and compared their responses to belowground and aboveground infestation by the root-feeding larvae and the leaf-chewing adults of the banded cucumber beetle Diabrotica balteata (Coleoptera: Chrysomelidae). Wild populations contained cucurbitacins in roots and cotyledons but not in leaves, whereas domesticated varieties lacked cucurbitacins in all tissues. Belowground infestation by D. balteata larvae did not increase cucurbitacin levels in the roots but triggered the expression of cucurbitacin biosynthetic genes, irrespective of domestication status, although the response varied among different varieties. Conversely, whereas wild squash had more leaf trichomes than domesticated varieties, the induction of leaf trichomes in response to herbivory was greater in domesticated plants. Leaf herbivory varied among varieties but there was a trend of higher leaf damage on wild squash than domesticated varieties. Overall, squash plants responded to both belowground and aboveground herbivory by activating chemical defense-associated gene expression in roots and upregulating their physical defense in leaves, respectively. While domestication suppressed both chemical and physical defenses, our findings suggest that it may enhance inducible defense mechanisms by increasing trichome induction in response to herbivory.
摘要：
植物驯化经常改变植物性状，包括对食草动物的化学和物理防御。在壁球中，驯化导致葫芦素和叶毛状体的水平降低，影响与昆虫的相互作用。然而,驯化对壁球诱导防御的影响仍然知之甚少。这里,我们调查了野生和驯化南瓜（南瓜）的化学和物理防御特性，并比较了它们对带状黄瓜甲虫Diabroticabalteata（鞘翅目：Chrysomelidae）的根食幼虫和嚼叶成虫对地下和地上侵染的反应。野生种群在根和子叶中含有葫芦素，但在叶片中没有，而驯化品种在所有组织中都缺乏葫芦素。Balteata幼虫的地下侵染并未增加根中葫芦素的水平，但触发了葫芦素生物合成基因的表达，不管驯化状态如何，尽管不同品种的反应不同。相反，而野生南瓜比驯化品种有更多的叶片毛状体，在驯化植物中，叶毛对草食动物的诱导作用更大。叶片草食性因品种而异，但与驯化品种相比，野生南瓜的叶片损害趋势更高。总的来说,南瓜植物通过激活根中与化学防御相关的基因表达并上调其在叶片中的物理防御来响应地下和地上草食动物，分别。虽然驯化抑制了化学和物理防御，我们的发现表明，它可能通过增加对草食动物的毛状体诱导来增强可诱导的防御机制。
