光敏色素互作因子4（HdPIF4）在异叶水蓑衣异形叶形态调控中的功能研究

植物叶形受环境调控而产生显著差异的现象称为“异形叶”。异形叶是水生植物适应环境的有效策略，但分子机制仍不清楚。我们前期对水/陆生境和不同光照下的异叶水蓑衣表型和基因表达进行了分析，发现光敏色素互作因子4（HdPIF4）的功能缺失会导致异形叶特性的改变，推测其可能在响应环境因子和调控异形叶形态方面起重要作用。本项目拟以异叶水蓑衣为材料，首先分析不同环境下HdPIF4的表达模式；其次，通过基因过表达和基因敲除等反向遗传学方法，结合形态解剖和生理测定，验证HdPIF4在异形叶形态调控中的功能；再利用凝胶迁移实验、染色质免疫共沉淀和转录组测序等技术，进一步验证HdPIF4对下游叶形发育的关键基因（如KNOX1）的调控。旨在阐明HdPIF4在异叶水蓑衣异形叶形态调控中的作用，揭示水生植物通过叶形变化适应生境的分子机制。

The phenomenon of heterophylly, differences in leaf shape regulated by the environment, is an efficient strategy for environmental adaptation in aquatic plants. However, the molecular mechanism remains unknown. We previously found that Phytochrome Interacting Factor 4 (HdPIF4) plays an important role in environmental response and regulation of heterophylly, through phenotype and expression analysis in Hygrophila difformis under different light, terrestrial or submerged conditions. We found that the features of heterophylly changed with functional deficit of HdPIF4. In this study, we will firstly use H. difformis as a model to perform gene expression analysis of HdPIF4 under different environmental conditions. Next, we will verify that the HdPIF4 gene functions in the regulation of heterophylly by reverse genetics techniques, such as gene knockout and gene overexpression, combined with morphological and physiological determination. Finally, we will study the regulation of HdPIF4 on downstream genes involved in leaf development (e.g. KNOX1) by Electrophoretic Mobility Shift Assay (EMSA), Chromatin Immunoprecipitation (ChIP) and transcriptomic sequencing. We aim to study the function of HdPIF4 in the regulation of heterophylly in H. difformis, and reveal the molecular mechanism of leaf form changes to environmental adaptation in aquatic plants.