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第2日 6月11日（火） 9:35～9:55 A会場（中ホール300）
- 2A-S-0935
Enigmatic Role of PR1 in Plant Biology Revealed by MS-Based Peptidomics: Transitioning from a Canonical Biomarker to a Key Cytokine Precursor for Plant Immunity
(ABRC, Academia Sinica)
oChen, Yet-Ran
This investigation addresses critical challenges in exploring plant signaling peptides, culminating in developing a more sensitive platform for comprehensive analysis of the plant endogenous peptidome. Within this framework, we uncovered a CAPE cytokine, a novel peptide cytokine family originating from precursor protein pathogenesis-related protein 1 (PR1). PR1 is a crucial immune protein induced by salicylic acid (SA) and has been used as a biomarker for defense against biological threats, but its function has been unclear for decades. Our investigations revealed that CAPE production is indispensable for plant immunity, as demonstrated through treatments with CAPE or localized expression of PR1 lacking the CAPE domain in the pr1 mutant. Furthermore, we identified the gene responsible for the Enzyme Specific to CAPE production (ESCAPE) that can release CAPE by proteolyzing PR1 in Arabidopsis. Genetic analyses underscored ESCAPE's pivotal role in the specific recognition and processing of CNYD in plants, which is crucial for the systemic elicitation of plant systemic acquired resistance (SAR) in response to the pathogen. Given the longstanding enigma surrounding PR1's function in plant immunity, our findings illuminate its fundamental role in regulating fundamental plant immunity, emphasizing the significance of the proteolytic action in generating immune cytokine CAPE from PR1 within this mechanism.