Functional characterization of the plastidial enzyme GPAT in microalgae and its potential role in lipid biosynthesis

作者：Hong Chen, Haiyan Ma, Lihua Yu, Song Zou, Yanhua Li, Yuanchen Lu, Mingkun Yang, Feng Ge, Li Yuan, Xiaoli Zeng, Cheng‐Cai Zhang, Kang‐Sup Yoon, Danxiang Han, Qiang Hu · 发表于：PLANT PHYSIOLOGY · 年份：2025 · DOI：10.1093/plphys/kiaf395 · 被引用次数：3 · 研究领域：Lipid metabolism and biosynthesis、Algal biology and biofuel production、Photosynthetic Processes and Mechanisms

Microalgae are a rich source of high-value natural products. The green microalga Chlamydomonas reinhardtii has long been used as a model organism for studying lipid metabolism in photosynthetic organisms. Here, we comprehensively characterized the enzymatic activity and substrate preferences of the plastidial glycerol-3-phosphate:acyl-CoA acyltransferase (GPAT1) from C. reinhardtii. Our results revealed that, in addition to GPAT activity, recombinant GPAT1 is associated with lysophosphatidic acid: acyl-CoA acyltransferase (LPAAT) activity. Notably, the membrane-bound form of GPAT1 displayed distinct acyl-donor preferences, favoring both C18:1 and C16:0 substrates in its LPAAT function. Knockdown of GPAT1 resulted in a reduced triacylglycerol content, particularly C16 species, under mixotrophic growth and nitrogen deprivation. Interestingly, GPAT1 knockdown triggered a compensatory upregulation of the endoplasmic reticulum-localized GPAT2, resulting in a significant increase in the content and yield of 1,3-olein-2-palmitin (OPO), an essential functional lipid used in infant formula. These findings provide insights into the function and physiological role of microalgal plastidial GPAT1 and highlight its potential as a biotechnological target for enhancing OPO production in microalgae.