Department of Bioenergy Science and Technology, Chonnam National University, Gwangju, Republic of Korea.
Department of Life Science, Sogang University, Seoul, Republic of Korea.
Plant Cell Physiol. 2019 Jun 1;60(6):1239-1249. doi: 10.1093/pcp/pcz032.
Malonyl-acyl carrier protein (ACP) is a key building block for the synthesis of fatty acids, which are important components of cell membranes, storage oils and lipid-signaling molecules. Malonyl CoA-ACP malonyltransferase (MCAMT) catalyzes the production of malonyl-ACP and CoA from malonyl-CoA and ACP. Here, we report that MCAMT plays a critical role in cell division and has the potential to increase the storage oil content in Arabidopsis. The quantitative real-time PCR and MCAMT promoter:GUS analyses showed that MCAMT is predominantly expressed in shoot and root apical meristems, leaf hydathodes and developing embryos. The fluorescent signals of MCAMT:eYFP were observed in both chloroplasts and mitochondria of tobacco leaf protoplasts. In particular, the N-terminal region (amino acid residues 1-30) of MCAMT was required for mitochondrial targeting. The Arabidopsis mcamt-1 and -2 mutants exhibited an embryo-lethal phenotype because of the arrest of embryo development at the globular stage. The transgenic Arabidopsis expressing antisense MCAMT RNA showed growth retardation caused by the defects in cell division. The overexpression of MCAMT driven by the promoter of the senescence-associated 1 (SEN1) gene, which is predominantly expressed in developing seeds, increased the seed yield and storage oil content of Arabidopsis. Taken together, the plastidial and mitochondrial MCAMT is essential for Arabidopsis cell division and is a novel genetic resource useful for enhancing storage oil content in oilseed crops.
丙二酰基辅酶 A (ACP) 是脂肪酸合成的关键构建模块，脂肪酸是细胞膜、储存油和脂质信号分子的重要组成部分。丙二酰 CoA-ACP 丙二酰转移酶 (MCAMT) 催化丙二酰-CoA 和 ACP 生成丙二酰-ACP 和 CoA。在这里，我们报告 MCAMT 在细胞分裂中起着关键作用，并有可能增加拟南芥中的储存油含量。定量实时 PCR 和 MCAMT 启动子：GUS 分析表明，MCAMT 主要在茎和根顶端分生组织、叶水孔和发育中的胚胎中表达。MCAMT:eYFP 的荧光信号在烟草叶原生质体的叶绿体和线粒体中均被观察到。特别是，MCAMT 的 N 端区域（氨基酸残基 1-30）是线粒体靶向所必需的。拟南芥 mcamt-1 和 -2 突变体表现出胚胎致死表型，因为胚胎发育在球形阶段停滞。表达反义 MCAMT RNA 的转基因拟南芥表现出生长迟缓，这是由于细胞分裂缺陷所致。由主要在发育种子中表达的衰老相关 1 (SEN1) 基因启动子驱动的 MCAMT 过表达增加了拟南芥的种子产量和储存油含量。总之，质体和线粒体 MCAMT 对拟南芥细胞分裂是必不可少的，是一种有用的新型遗传资源，可用于提高油料作物的储存油含量。
