Linking Populus nigra metabotypes to genetic variation and plant-herbivore interactions

黑杨树（Populus nigra）具有丰富多样的特殊代谢物，是分析植物与食草动物相互作用的理想选择。第一个资助期的目的是评估黑杨树对Lymantria dispar取食的组成型和应激诱导的挥发性和非挥发性化学型的化学多样性，并确定这种反应与基因表达变化相关的表型可塑性。我们发现，在草食过程中，树萜烯的排放表现出特定的来源模式，并且摄食的严重程度因基因型而异。在UBC温哥华的一个普通花园中，对P. trichocarpa的分析表明，叶片的代谢差异可以用生物气候和地理影响来解释，允许将起源分配到单个河流系统。第二个资助期将确定干旱胁迫下黑杨树器官种内化学多样性和可塑性以及地上和地下草食。干旱胁迫被认为会导致植物-食草动物相互作用的变化，从而导致对食草动物的器官特异性反应。实验将在根瘤菌表型平台上进行，该平台的非侵入性测量将允许检测应力诱导的变化，并为代谢组学分析提供组织特异性样本。对于选定的化学型，使用多试管系统以高时间分辨率记录植物的气体交换，包括挥发性有机化合物排放。非靶向代谢组学将用于确定各种组织和器官（幼叶/老叶、韧皮部/树皮、木质部和根）中的代谢组网络。该“代谢图谱”可以与项目P1和P3-P7的dulcamara和Tanacetum vulgare的数据集进行比较。与P8合作，我们将研究代谢组网络如何与基因表达和遗传变异的变化相关。我们将与P1合作，在我们的联合共同园林实验中记录黑杨树不同化学表型在自然条件下的适应性和适合度。化学多样性可塑性实验将在我们慕尼黑的设施中进行，我们将专门对光学生物特征进行非侵入性分析。该项目的分析将有助于虚拟植物（P9）的发展和化学多样性指数（P10）的改善，并有助于了解环境因素如何改变化学多样性以及这些变化对植物食草性可能产生的生态后果。

Black poplar (Populus nigra) has an immense diversity of specialized metabolites and is ideally suited for the analysis of plant-herbivore interactions. The objective of the first funding period was to assess the chemodiversity of constitutive and stress-induced volatile and non-volatile chemotypes in black poplars in response to feeding by Lymantria dispar and to determine the phenotypic plasticity of this response in relation to changes in gene expression. We showed that tree terpene emissions during herbivory exhibited origin-specific patterns and that the severity of feeding varied among genotypes. Analyses of P. trichocarpa, in a common garden at UBC Vancouver showed that metabolic differences in leaves could be explained by bioclimatic and geographic influences, allowing assignment of origins to individual river systems. A second funding period will determine the intraspecific chemodiversity and plasticity of black poplar organs under drought stress and above- and belowground herbivory. Drought stress is hypothesized to lead to changes in plant-herbivore interactions that result in organ-specific responses to herbivory. Experiments will be conducted on a rhizotron phenotyping platform whose non-invasive measurements will allow detection of stress-induced changes and provide tissue-specific samples for metabolomics analyses. For selected chemotypes, a multicuvette system is used to record gas exchange, including volatile organic compound emissions, from plants with high temporal resolution. Non-targeted metabolomics will be used to determine metabolome networks in various tissues and organs (young/old leaves, phloem/bark, xylem, and roots). This ‘metabolic atlas’ can be compared with the datasets from projects P1 and P3-P7 for Solanum dulcamara and Tanacetum vulgare. In collaboration with P8, we will investigate how metabolome networks are associated with changes in gene expression and genetic variation. In collaboration with P1, we will record the adaptability and fitness of different chemical phenotypes of black poplar under natural conditions in our joint common garden experiment. The chemodiversity plasticity experiment will be conducted at our facilities in Munich, and we will specifically conduct non-invasive analyses of optical biometric traits. The analyses in the project will contribute to the development of virtual plants (P9) and to the improvement of chemodiversity indices (P10), and will help to understand how chemodiversity is altered by environmental factors and what ecological consequences these changes may have for plant herbivory.