Thompson M N, Cohen Z P, Merrell D, Helms A M
Department of Entomology, Texas A&M University, College Station, TX, USA.
USDA-ARS, Southern Plains Agricultural Research Center, College Station, TX, USA.
Plant Biol (Stuttg). 2024 Aug 20. doi: 10.1111/plb.13709.
When attacked by insect herbivores, plants emit blends of chemical compounds known as herbivore-induced plant volatiles (HIPVs). Although HIPVs are produced both aboveground and belowground, how HIPVs vary across plant tissues remains unresolved, as do the selective forces shaping interspecific HIPV emission patterns. Here, we compared foliar and root HIPVs within and among closely related plant species and evaluated if different eco-evolutionary forces, including plant domestication, coexistence histories with herbivores, or phylogenetic relatedness, explain HIPV blends. To examine aboveground and belowground patterns in HIPVs, we compared leaf and root volatile profiles for six species in the Cucurbitaceae that differed in domestication status and coexistence history with specialist insect herbivores. We predicted that within-species HIPVs from different tissues would be more similar than HIPV blends among different species, and that plant volatile chemodiversity was reduced by domestication and enhanced by coexistence histories with herbivores. We found that herbivory induced both quantitative and qualitative changes in volatile emissions across all plant species, which were more pronounced aboveground than belowground. Each species produced tissue-specific HIPVs, and foliar and root HIPVs differed among species. Contrary to our predictions, plant domestication enhanced foliar volatile diversity, while coexistence histories with herbivores reduced foliar and root volatile diversity. Additionally, phylogenetic relatedness did not correlate with aboveground or belowground volatiles. Overall, this work furthers our understanding of the eco-evolutionary forces driving patterns in aboveground and belowground HIPV emissions, elucidating an important and previously undescribed component of within-plant variation in chemodiversity.
当受到昆虫食草动物攻击时，植物会释放出被称为食草动物诱导植物挥发物（HIPVs）的化合物混合物。尽管地上和地下都会产生HIPVs，但HIPVs在不同植物组织中的差异以及塑造种间HIPV排放模式的选择力仍未得到解决。在这里，我们比较了近缘植物物种内部和之间的叶片和根系HIPVs，并评估了不同的生态进化力量，包括植物驯化、与食草动物的共存历史或系统发育相关性，是否能解释HIPV混合物。为了研究HIPVs的地上和地下模式，我们比较了葫芦科六个物种的叶片和根系挥发物谱，这些物种在驯化状态以及与专食性昆虫食草动物的共存历史方面存在差异。我们预测，同一物种不同组织的HIPVs比不同物种的HIPV混合物更相似，并且植物挥发物化学多样性会因驯化而降低，因与食草动物的共存历史而增加。我们发现，食草作用在所有植物物种中都诱导了挥发性排放的数量和质量变化，地上变化比地下更明显。每个物种都产生组织特异性的HIPVs，并且叶片和根系HIPVs在物种间存在差异。与我们的预测相反，植物驯化增强了叶片挥发物多样性，而与食草动物的共存历史降低了叶片和根系挥发物多样性。此外，系统发育相关性与地上或地下挥发物均无关联。总体而言，这项工作进一步加深了我们对驱动地上和地下HIPV排放模式的生态进化力量的理解，阐明了植物化学多样性内部变异中一个重要且此前未被描述的组成部分。
