Department of Botany, University of British Columbia, 6270 University Boulevard, Vancouver, BC, Canada.
Department of Biology, Algoma University, Sault Ste Marie, ON, Canada.
Plant Cell Physiol. 2019 May 1;60(5):1041-1054. doi: 10.1093/pcp/pcz019.
Long-chain acyl-CoA synthetases (LACSs) play diverse and essential roles in lipid metabolism. The genomes of model eukaryotic organisms encode multiple LACS genes, and the substrate specificities of LACS homologs often overlap substantially. Homologous LACSs tend to differ in their expression patterns, localizations, and, by extension, the metabolic pathways to which they contribute. The Arabidopsis genome encodes a family of nine LACS genes, which have been characterized largely by reverse genetic analysis of mutant phenotypes. Because of redundancy, distinguishing the contributions of some Arabidopsis LACS genes has been challenging. Here, we have attempted to clarify the functions of LACSs that functionally overlap by synopsizing the results of previous work, isolating a suite of higher-order mutants that were previously lacking, and analyzing oil, wax, cutin, cuticle permeability, fertility and growth phenotypes. LACS1, LACS2, LACS4, LACS8 and LACS9 all affect cuticular lipid metabolism, but have different precise roles. Seed set, seed weight and storage oil amounts of higher-order lacs1, lacs2, lacs4, lacs8 and lacs9 mutants vary greatly, with these traits subject to different effects of fertility and oil synthesis defects. LACS4, LACS8 and LACS9 have partially redundant roles in development, as lacs4 lacs8 and lacs4 lacs9 double mutants are dwarf. lacs4 lacs8 lacs9 triple mutants were not recovered, and are assumed to be non-viable. Together, these results sketch a complex network of functions and functional interactions within the Arabidopsis LACS gene family.
长链酰基辅酶 A 合成酶（LACSs）在脂质代谢中发挥着多样化且至关重要的作用。模式真核生物的基因组编码多个 LACS 基因，并且 LACS 同源物的底物特异性通常存在很大程度的重叠。同源 LACS 往往在其表达模式、定位以及由此产生的代谢途径方面存在差异。拟南芥基因组编码一个包含 9 个 LACS 基因的家族，这些基因的特征主要通过对突变表型的反向遗传学分析来确定。由于存在冗余性，区分一些拟南芥 LACS 基因的贡献具有挑战性。在这里，我们试图通过综合先前工作的结果、分离以前缺乏的一套更高阶突变体并分析油、蜡、角质、角质层渗透性、育性和生长表型，来阐明功能重叠的 LACS 的功能。LACS1、LACS2、LACS4、LACS8 和 LACS9 都影响角质层脂质代谢，但具有不同的精确作用。高阶 lacs1、lacs2、lacs4、lacs8 和 lacs9 突变体的种子结实率、种子重量和储存油含量差异很大，这些性状受到育性和油脂合成缺陷的不同影响。LACS4、LACS8 和 LACS9 在发育过程中具有部分冗余的作用，因为 lacs4 lacs8 和 lacs4 lacs9 双突变体矮小。未能回收 lacs4 lacs8 lacs9 三重突变体，并且假定其是不可存活的。总之，这些结果描绘了拟南芥 LACS 基因家族中功能和功能相互作用的复杂网络。
