植物能够通过细胞表面模式识别受体（PRRs）识别病原相关分子模式和植物内源信号分子启动免疫发生。当前，我们对PRRs识别植物内源分子调节免疫发生的机制了解甚少。近期，申请人利用生物信息学方法筛选了一类拟南芥分泌肽前体prePIPPs，并发现该家族蛋白C端保守的15个氨基酸组成的多肽PIPP1-15aa能够显著诱导活性氧产生等免疫反应，表明该家族蛋白能够参与植物免疫。本项目将继续开展以下研究：（一）分析prePIPPs的表达模式；（二）通过过表达表型分析和质谱分析鉴定该分泌肽前体对应的成熟分泌肽PIPPs，并分析该分泌肽的免疫相关功能；（三）通过RNA-seq技术分析PIPPs调控的拟南芥基因表达，初步揭示PIPPs参与的免疫信号途径；（四）以部分细胞表面受体激酶为研究对象，分析参与PIPPs识别的可能机制。以上研究将有助于我们揭示该类分泌肽的免疫相关功能，加深我们对植物免疫调节机制的理解。

One of the major plant immune signaling pathways is triggered by plant plasma membrane-located pattern recognition receptors (PRRs) upon perception of exogenous pathogen-associated molecular partterns (PAMPs) and endogenous signal molecules. Currently, it is largely unknown how endogenous molecules are perceived and invovled in plant immune regulation. Recently, we identified a novel gene family of secreted peptide precursors, termed prePIPPs, in Arabidopsis through an in-silico approach. In this project, four aspects of studies will be suggested as followed: First, the analysis of the gene expression patterns. Second, The PIPP peptide will be identified through phenotypic analyses of trangenic lines overexpressing full-length and various C-terminally truncated prePIPPs tohether with liquid chromatography–mass spectrometry (LC-MS)-based sequence analysis. Then, the chemical synthetic peptide will be used to test its immune-related activities. Third, we will employ the RNA-seq technique to analyze the PIPP-regulated gene expression, and try to get some clues for elucidation of the peptide-regulated immune signaling pathways. Fourth, the loss-of-function mutants of some LRR-RLKs, including Flagellin-sensitive 2 (FLS2), BRASSINOSTEROID INSENSITIVE 1-associated receptor kinase 1 (BAK1) and some XI subfamily members of leucine-rich repeat receptor-like kinases (LRR-RLKs), will be used to analyze the potential mechnism of PIPPs recognition. The illumination of the above problems will not only largerly uncover the function of PIPPs invovled in plant immunity, but also advance our understainding of the molecular mechnism underlying plant immune regulation.