Ubiquitously expressed in plants, the plant-specific insert (PSI) of typical plant aspartic proteases (tpAPs) has been associated with plant development, stress response, and defense processes against invading pathogens. Despite sharing high sequence identity, structural studies revealed possible different mechanisms of action among species. The PSI induces signaling pathways of defense hormones in vivo and demonstrates broad-spectrum activity against phytopathogens in vitro. Recent characterization of the PSI‐tpAP relationship uncovered novel, nonconventional intracellular protein transport pathways and improved tpAP production yields for industrial applications. In spite of research to date, relatively little is known about the structure‐function relationships of PSIs. A comprehensive understanding of their biological roles may benefit plant protection strategies against virulent phytopathogens.

典型的植物天冬氨酸蛋白酶（tpAPs）的植物特异性插入片段（PSI）在植物中无处不在表达，与植物的发育，胁迫反应以及对入侵病原体的防御过程有关。尽管具有较高的序列同一性，结构研究显示物种间可能存在不同的作用机理。的PSI诱导信令防御激素途径在体内和证明了对抗植物病原体的广谱活性的体外。最近对PSI-tpAP关系的表征揭示了新颖的，非常规的细胞内蛋白转运途径，并提高了工业应用中的tpAP产量。尽管迄今为止进行了研究，但对PSI的结构-功能关系知之甚少。对其生物学作用的全面了解可能有益于植物保护策略以抵抗强力植物病原体。