Real-time plant evolution in a multitrophic community

了解多营养群落的进化过程是进化生物学中的一个基本而突出的挑战。在自然界中，植物受到食草动物的威胁，同时也受到各种微生物的侵袭。越来越多的证据表明，植物微生物区系改变了宿主对食草动物的防御，并被食草动物改变。然而，植物与其微生物群之间的相互作用在多大程度上影响了草食压力下植物进化的过程和轨迹，目前尚不清楚。本项目旨在通过实时研究草食驱动植物进化的过程和机制来弥合这一认识差距。我们将以生长最快的植物之一--巨型浮萍(Spirodela PolyRha)为模型系统，进行“选择和重测序”实验。我们将使用池塘蜗牛(Lymneea Stagnalis)对多根链霉菌种群施加草食压力，该种群由150个天然种质组成，代表了该物种的大部分遗传多样性。试验在大田条件下进行，历时6个月，相当于30多个世代。我们将量化草食在多大程度上推动植物表型、等位基因频率和微生物区系的变化。我们将进一步评估所观察到的植物性状和等位基因频率变化的适合性后果，并调查植物微生物区系的变化是否以及如何改变植食性对植物防御的选择。这项研究结合了实验进化和前沿的遗传和基因组工具，将通过阐明多营养群落中植物防御进化的机制和过程，推动植物-食草动物相互作用领域的研究边界。该项目产生的资源不仅将为植物实验进化开辟新的研究途径，还将加快浮萍的工业应用。

Understanding the process of evolution in multitrophic communities represents a fundamental and outstanding challenge in evolutionary biology. In nature, plants are threatened by herbivores and simultaneously colonized by diverse microorganisms. Accumulating evidence suggests that the plant microbiota changes the host’s defense against herbivores and is altered by herbivory. However, it remains unknown to what extent interactions between plants and their microbiota affect the process and trajectory of plant evolution under herbivore pressure.This project aims to close this knowledge gap by investigating the process and mechanism of herbivory-driven plant evolution in real-time. We will perform “selection and resequence” experiments using the giant duckweed (Spirodela polyrhiza), one of the fastest-growing plants, as a model system. We will use the pond snail (Lymnaea stagnalis) to impose herbivory pressure on S. polyrhiza populations consisting of 150 natural accessions that represent the majority of genetic diversity in this species. The experiment will be conducted under field conditions and last for 6 months, which corresponds to more than 30 generations for S. polyrhiza. We will quantify the extent to what herbivory drives changes in the plant phenotype, allele frequency, and microbiota. We will further assess the fitness consequences of the observed changes in plant traits and allele frequencies, and investigate whether and how changes in the plant microbiota alter the herbivory-imposed selection on plant defenses. Using a combination of experimental evolution and cutting-edge genetic and genomic tools, this research will push the research boundaries in the field of plant-herbivore interaction by elucidating the mechanisms and processes of plant defense evolution in a multitrophic community. The resources generated in this project will not only open new research avenues of plant experimental evolution, but will also accelerate the use of duckweeds for industrial applications.