植物依靠天然免疫系统对抗各种病原微生物。模式识别受体识别微生物保守分子结构启动天然免疫系统的第一道防线。遗传转化模式识别受体可使植物获得广谱和高效的抗性，然而使模式识别受体做出适当的识别和适时适度的表达是该策略进入应用领域的主要挑战。..FLS2是第一个被鉴定的植物模式识别受体。申请人发现多个木本植物FLS2基因具有高丰度可变剪接异构体，且杨树FLS2可变剪接异构体抑制植物对细菌鞭毛蛋白的应答。申请人拟以杨树FLS2可变剪接为切入点开展研究，利用蛋白质相互作用技术分析异构体的作用机制，结合逐段缺失的FLS2的遗传转化、酵母单杂交和病毒介导的基因沉默技术分析可变剪接差异诱导的调控机制，进而在小叶杨群体中分析FLS2复等位基因的可变剪接差异，以及研究其它植物中FLS2转录异构体的功能。本项目的实施有利于模式识别受体调控机制的揭示，促进遗传转化和编辑模式识别受体的基因工程育种。

Plants rely on innate immune system to defend themselves against a variety of pathogenic microbes, of which the first line of defense is mediated by plant pattern recognition receptors (PRRs) perceiving pathogen-associated molecular patterns (PAMPs). Heterologously expressing PRRs can confer plants broad-spectrum and efficient resistance to pathogens. However, there exists challenges in employing PRRs as they need to avoid perceiving beneficial microbes and be activated against pathogens at the proper time and to an appropriate degree in different target crops...FLS2 was the first identified PRR in plant. We found that high-abundant transcript variants (TVs) derived from alternative splicing FLS2 existed in multiple woody perennial plants and the TVs of poplar FLS2 inhibited immune response of transgenic plants upon bacterial flagellin treatment. Therefore, we plan to develop further study on the alternative splicing of poplar FLS2 genes. Our research proposal includes that exploring work mechanism of FLS2 variants inhibiting immune responses by protein interaction methods, resolving differential regulation mechanism of poplar FLS2 TVs by combined transformation of a series of FLS2 partial deletion constructs, yeast one-hybrid and virus-induced gene silencing (VIGS) methods, analyzing the difference of FLS2 alternative splicing in Populus simonii population and identifying function of different FLS2 TVs in other plants. These studies could accelerate the study of regulation mechanism of plant PRRs and promote genetic engineering breeding that based on transferring and editing PRR genes.