Biology Department, Brookhaven National Laboratory, Upton, New York, 11973, USA.
State Key Laboratory of Crop Stress Biology for Arid Areas and Institute of Future Agriculture, Northwest A&F University, Yangling, Shanxi, China.
Plant J. 2023 Jul;115(2):335-350. doi: 10.1111/tpj.16228. Epub 2023 Apr 17.
Two parallel pathways compartmentalized in the chloroplast and the endoplasmic reticulum contribute to thylakoid lipid synthesis in plants, but how these two pathways are coordinated during thylakoid biogenesis and remodeling remains unknown. We report here the molecular characterization of a homologous ADIPOSE TRIGLYCERIDE LIPASE-LIKE gene, previously referred to as ATGLL. The ATGLL gene is ubiquitously expressed throughout development and rapidly upregulated in response to a wide range of environmental cues. We show that ATGLL is a chloroplast non-regioselective lipase with a hydrolytic activity preferentially towards 16:0 of diacylglycerol (DAG). Comprehensive lipid profiling and radiotracer labeling studies revealed a negative correlation of ATGLL expression and the relative contribution of the chloroplast lipid pathway to thylakoid lipid biosynthesis. Additionally, we show that genetic manipulation of ATGLL expression resulted in changes in triacylglycerol levels in leaves. We propose that ATGLL, through affecting the level of prokaryotic DAG in the chloroplast, plays important roles in balancing the two glycerolipid pathways and in maintaining lipid homeostasis in plants.
植物类囊体膜脂质合成由叶绿体和内质网中两个平行途径分隔开来，但这两个途径在类囊体生物发生和重塑过程中是如何协调的仍不清楚。我们在此报告了一个同源的脂肪甘油三酯脂肪酶样基因（先前称为 ATGLL）的分子特征。ATGLL 基因在整个发育过程中广泛表达，并能快速响应各种环境信号而上调。我们表明，ATGLL 是一种叶绿体非区域选择性脂肪酶，对二酰基甘油（DAG）的 16:0 具有水解活性。全面的脂质分析和放射性示踪标记研究表明，ATGLL 的表达与叶绿体脂质途径对类囊体脂质生物合成的相对贡献呈负相关。此外，我们还表明，ATGLL 表达的遗传操作导致叶片中三酰基甘油水平的变化。我们提出，ATGLL 通过影响叶绿体中原核 DAG 的水平，在平衡两个甘油酯途径和维持植物脂质动态平衡方面发挥重要作用。
