Cao Jing, Cheng Gang, Wang Lu, Maimaitijiang Tayier, Lan Haiyan
Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi, China.
Front Plant Sci. 2021 Aug 30;12:665279. doi: 10.3389/fpls.2021.665279. eCollection 2021.
Phosphoenolpyruvate carboxylase (PEPC) plays pivotal roles in the carbon fixation of photosynthesis and a variety of metabolic and stress pathways. belongs to a single-cellular C species and carries out a photosynthetic pathway in an unusually elongated chlorenchyma cell, which is expected to have PEPCs with different characteristics. To identify the different isoforms of genes in and comparatively analyze their expression and regulation patterns as well as the biochemical and enzymatic properties in this study, we characterized a bacterial-type PEPC (BTPC; SaPEPC-4) in addition to the two plant-type PEPCs (PTPCs; SaPEPC-1 and SaPEPC-2) using a genome-wide identification. presented a lower expression level in all test combinations with an unknown function; two SaPTPCs showed distinct subcellular localizations and different spatiotemporal expression patterns but positively responded to abiotic stresses. Compared to , the expression of specifically in chlorenchyma cell tissues was much more active with the progression of development and under various stresses, particularly sensitive to light, implying the involvement of in a C photosynthetic pathway. In contrast, was more like a non-photosynthetic PEPC. The expression trends of two SaPTPCs in response to light, development, and abiotic stresses were also matched with the changes in PEPC activity (native) or (recombinant), and the biochemical properties of the two recombinant SaPTPCs were similar in response to various effectors while the catalytic efficiency, substrate affinity, and enzyme activity of SaPEPC-2 were higher than that of SaPEPC-1 All the different properties between these two SaPTPCs might be involved in transcriptional (e.g., specific -elements), posttranscriptional [e.g., 5'-untranslated region (5'-UTR) secondary structure], or translational (e.g., PEPC phosphorylation/dephosphorylation) regulatory events. The comparative studies on the different isoforms of the PEPC gene family in may help to decipher their exact role in C photosynthesis, plant growth/development, and stress resistance.
磷酸烯醇式丙酮酸羧化酶（PEPC）在光合作用的碳固定以及各种代谢和胁迫途径中发挥着关键作用。[该物种]属于单细胞C4植物，在异常细长的叶肉细胞中进行光合途径，预计其具有不同特性的PEPC。为了在本研究中鉴定[该物种]中PEPC基因的不同同工型，并比较分析它们的表达和调控模式以及生化和酶学特性，我们通过全基因组鉴定，除了两种植物型PEPC（PTPC；SaPEPC - 1和SaPEPC - 2）之外，还鉴定了一种细菌型PEPC（BTPC；SaPEPC - 4）。[SaPEPC - 4]在所有测试组合中表达水平较低且功能未知；两种SaPTPC表现出不同的亚细胞定位和不同的时空表达模式，但对非生物胁迫有积极响应。与[SaPEPC - 4]相比，[SaPEPC - 1和SaPEPC - 2]在叶肉细胞组织中的表达随着发育进程和在各种胁迫下，特别是对光更敏感，活性明显更高，这意味着[SaPEPC - 1和SaPEPC - 2]参与C4光合途径。相反，[SaPEPC - 4]更像是一种非光合PEPC。两种SaPTPC对光、发育和非生物胁迫的响应表达趋势也与PEPC活性（天然）或（重组）的变化相匹配，并且两种重组SaPTPC的生化特性在对各种效应物的响应中相似，而SaPEPC - 2的催化效率、底物亲和力和酶活性高于SaPEPC - 1。这两种SaPTPC之间所有不同的特性可能涉及转录（例如，特定的顺式作用元件）、转录后[例如，5'非翻译区（5'-UTR）二级结构]或翻译（例如，PEPC磷酸化/去磷酸化）调控事件。对[该物种]中PEPC基因家族不同同工型的比较研究可能有助于阐明它们在C4光合作用、植物生长/发育和抗逆性中的确切作用。
