Tu Jiaqi, Feng Lanlan, Hong Yanbin, Liu Qiuyun, Huang Xia, Li Yin
Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China.
Crops Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China.
Plants (Basel). 2021 Feb 14;10(2):365. doi: 10.3390/plants10020365.
Phosphopyruvate carboxylase (PEPC) is a ubiquitous cytosolic enzyme that catalyzes the irreversible β-carboxylation of phosphopyruvate (PEP) in presence of HCO to produce oxaloacetate (OAA) during carbon fixation and photosynthesis. It is well accepted that genes are expressed in plants upon stress. also supports the biosynthesis of biocompatible osmolytes in many plant species under osmotic stress. There are five isoforms of found in peanut ( L.), namely, , , , and . Quantitative real-time polymerase chain reaction (qRT-PCR) analysis revealed that the gene expression patterns of these genes were different in mature seeds, stems, roots, flowers, and leaves. The expression of all the plant type PEPC (s) ( and ) was relatively high in roots, while the bacterial type PEPC () showed a remarkable expression level in flowers. Principal component analysis (PCA) result showed that and are correlated with each other, indicating comparatively associations with roots, and have a very close relationship with flowers. In order to investigate the function of these s, the fragments of these five cDNA were cloned and expressed in (). The recombinant proteins contained a conserved domain with a histidine site, which is important for enzyme catalysis. Results showed that protein fragments of , and had remarkable expression levels in . These three recombinant strains were more sensitive at pH 9.0, and recombinant strains carrying and fragments exhibited more growth than the control strain with the presence of PEG6000. Our findings showed that the expression of the fragments may enhance the resistance of transformed to osmotic stress.
磷酸烯醇式丙酮酸羧化酶（PEPC）是一种普遍存在于细胞质中的酶，在碳固定和光合作用过程中，它在HCO存在的情况下催化磷酸烯醇式丙酮酸（PEP）不可逆的β羧化反应，生成草酰乙酸（OAA）。人们普遍认为，基因在植物受到胁迫时会表达。它还支持许多植物物种在渗透胁迫下生物相容性渗透溶质的生物合成。在花生（L.）中发现了五种PEPC同工型，即、、、和。定量实时聚合酶链反应（qRT-PCR）分析表明，这五个基因在成熟种子、茎、根、花和叶中的基因表达模式不同。所有植物型PEPC（和）在根中的表达相对较高，而细菌型PEPC（）在花中的表达水平显著。主成分分析（PCA）结果表明，和相互关联，表明与根有相对较强的关联，而与花有非常密切的关系。为了研究这些PEPC的功能，克隆了这五个PEPC cDNA的片段并在（）中表达。重组蛋白包含一个带有组氨酸位点的保守结构域，这对酶催化很重要。结果表明，、和的蛋白片段在中有显著的表达水平。这三个重组菌株在pH 9.0时更敏感，携带和片段的重组菌株在有PEG6000存在时比对照菌株生长得更多。我们的研究结果表明，PEPC片段的表达可能增强转化后的对渗透胁迫的抗性。
