Phospholipases hydrolyze glycerophospholipids and generate diverse lipid-derived molecules with secondary messenger activity. Out of these, phospholipase C (PLC) specifically cleaves the phospholipids at ester linkages and yields diacylglycerol (DAG) and phosphorylated head groups. PLCs are classified further as phosphatidylinositol-specific PLCs (PI-PLCs) and non-specific PLCs with biased specificity for phosphatidylcholine (NPC/PC-PLC). In the present report, we identified and characterized PLC genes in the genomes of three orchids, Phalaenopsis equestris (seven PePLCs), Dendrobium catenatum (eight DcPLCs), and Apostasia shenzhenica (seven AsPLCs). Multiple sequence alignment analysis confirmed the presence of conserved X and Y catalytic domains, calcium/lipid-binding domain (C2 domain) at the C terminal region, and EF-hand at the N-terminal region in PI-PLC proteins and esterase domain in PC-PLC. Systematic phylogenetic analysis established the relationship of the PLC protein sequences and clustered them into two groups (PI-PLC and PC-PLC) along with those of Arabidopsis thaliana and Oryza sativa. Gene architecture studies showed the presence of nine exons in all PI-PLC genes while the number varied from one to five in PC-PLCs. RNA-seq-based spatio-temporal expression profile for PLC genes was generated, which showed that PePC-PLC1, PePC-PLC2A, DcPC-PLC1A, DcPC-PLC1B, DcPC-PLC2, DcPC-PLC1B, and AsPC-PLC1 had significant expression in all reproductive and vegetative tissues. The expression profile is matched to their upstream cis-regulatory promoter elements, which indicates that PLC genes have a role in various growth and development processes and during stress responses. The present study unwrapped the opportunity for functional characterization of selected PLC genes in planta for plant improvement.

中文翻译：

---

三种具有经济重要性的兰花中磷脂酶 C (PLC) 基因家族的全基因组表征和表达谱

磷脂酶水解甘油磷脂并产生多种具有二级信使活性的脂质衍生分子。其中，磷脂酶 C (PLC) 在酯键处特异性裂解磷脂并产生二酰基甘油 (DAG) 和磷酸化的头部基团。PLC 进一步分为磷脂酰肌醇特异性 PLC (PI-PLC) 和对磷脂酰胆碱具有偏向特异性的非特异性 PLC (NPC/PC-PLC)。在本报告中，我们鉴定并表征了三种兰花、蝴蝶兰（七个 PePLC）、链状石斛（八个 DcPLC）和 Apostasia shenzhenica（七个 AsPLC）基因组中的 PLC 基因。多序列比对分析证实了在 C 端区域存在保守的 X 和 Y 催化域、钙/脂质结合域（C2 域），和 EF-hand 位于 PI-PLC 蛋白的 N 端区域和 PC-PLC 中的酯酶结构域。系统发育分析确定了 PLC 蛋白质序列的关系，并将它们与拟南芥和水稻的蛋白质序列聚类为两组（PI-PLC 和 PC-PLC）。基因结构研究表明，所有 PI-PLC 基因中都存在 9 个外显子，而 PC-PLC 中的数量从 1 到 5 个不等。生成基于 RNA-seq 的 PLC 基因时空表达谱，表明 PePC-PLC1、PePC-PLC2A、DcPC-PLC1A、DcPC-PLC1B、DcPC-PLC2、DcPC-PLC1B 和 AsPC-PLC1 有显着表达在所有生殖和营养组织中。表达谱与其上游顺式调节启动子元件相匹配，这表明 PLC 基因在各种生长发育过程和应激反应中发挥作用。本研究为植物改良中选定的 PLC 基因的功能表征提供了机会。