植物过氧化物酶体是脂肪酸代谢和自由基清除的重要场所。及时地清除不同发育阶段和环境条件下产生的废弃的、氧化损伤的或冗余的过氧化物酶体，才能保证植物的正常生长发育并适应各种胁迫环境。尽管目前已知植物中不再需要的过氧化物酶体通过选择性细胞自噬在液泡降解，然而该途径中最关键的蛋白-自噬受体尚未得到鉴定。在本项目的前期工作中，我们发现PDF1与过氧化物酶体膜蛋白PEX3以及细胞自噬核心蛋白ATG8、ATG11互作，敲除PDF1可抑制lon2突变体中过氧化物酶体的降解，而且pdf1突变体中过氧化物酶体形态发生变化。在此工作基础之上，本项目拟解析PDF1作为自噬受体如何特异性地识别待降解的过氧化物酶体并将其招募至自噬体，进而研究PDF1的功能如何被磷酸化修饰调控，最终阐明PDF1如何在植物发育的不同阶段和逆境胁迫过程中介导过氧化物酶体降解，从而维持细胞内过氧化物酶体稳态的作用机理和生理意义。

Plant peroxisomes are crucial organelles for beta-oxidation of fatty acids, detoxification of reactive oxygen species, photorespiration, biosynthesis of plant hormone, and various secondary metabolic reactions. Obsolete, oxidative damaged, and redundant peroxisomes are need to be immediately cleared to maintain plant growth and development and in response to a variety of environmental stresses. Although it has been known that plant peroxisomes are degraded in the vacuole by pexophagy, the selective receptor in pexophagy pathway remains elusive. In our preliminary studies, we found that PDF1 (peroxisome degadation factor1) is a candidate of pexophagy receptors. PDF1 interacts with peroxisomal membrane protein PEX3 and one of the core components ofautophagy machinery, ATG8. Furthermore, we found that knock out PDF1 in lon2 mutant suppress the degradation of peroxisome and resulted in the restoration of peroxisomal matrix proteins, PDMH and thiolase. Based on these preliminary data, we propose to investigate how activated PDF1 recognizes obsolete, oxidative damaged, and redundant peroxisomes, interacts with autophagy machinery and delivers peroxisomes to be degraded in the vacuole. This project will shed light on how PDF1 mediated pexophagy on peroxisome homeostasis to sustain normal plant growth and development and adapt to variety of environmental stresses.