Towards a comprehensive understanding of the chlorophyll breakdown pathway

为了更好地了解植物中的叶绿素降解途径，我们研究了叶绿素酶的功能，它是一种常见的植物酶，催化叶绿素的裂解形成叶绿素内酯和植醇。我们发现该酶定位于内质网和液泡膜。只有当细胞被破坏时，这种酶才能有效地催化叶绿素的形成。具有遗传增强的CLH活性的拟南芥叶片在取食食草性昆虫Spotor tera幼虫时表现出毒性。纯化后的叶绿素部分抑制幼虫的生长。我们发现，叶绿素酶和叶绿素形成了一个针对咀嚼食草动物的双组分防御系统。

For better understanding of the chlorophyll breakdown pathway in plants, we investigated the function of chlorophyllase, a common plant enzyme that catalyzes the cleavage of chlorophyll to form chlorophyllide and phytol. We found that this enzyme is localized in the endoplasmic reticulum and the tonoplast. This enzyme actively catalyzes chlorophyllide formation only when cells are disrupted. Arabidopsis leaves with genetically enhanced CLH activity exhibit toxicity when fed to Spodoptera larvae, an insect herbivore. Purified chlorophyllide partially suppresses the growth of the larvae. We showed that chlorophyllase and chlorophyll form a two-component defense system against chewing herbivores.