Wei Yangyang, Li Zhaoguo, Wedegaertner Tom C, Jaconis Susan, Wan Sumei, Zhao Zilin, Liu Zhen, Liu Yuling, Zheng Juyun, Hake Kater D, Peng Renhai, Zhang Baohong
Research Base, State Key Laboratory of Cotton Biology, Anyang Institute of Technology, Anyang 455000, China.
School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China.
Plants (Basel). 2022 May 31;11(11):1482. doi: 10.3390/plants11111482.
Phosphoenolpyruvate carboxylase (PEPC) is an important enzyme in plants, which regulates carbon flow through the TCA cycle and controls protein and oil biosynthesis. Although it is important, there is little research on PEPC in cotton, the most important fiber crop in the world. In this study, a total of 125 PEPCs were identified in 15 genomes. All PEPC genes in cotton are divided into six groups and each group generally contains one PEPC member in each diploid cotton and two in each tetraploid cotton. This suggests that PEPC genes already existed in cotton before their divergence. There are additional PEPC sub-groups in other plant species, suggesting the different evolution and natural selection during different plant evolution. PEPC genes were independently evolved in each cotton sub-genome. During cotton domestication and evolution, certain PEPC genes were lost and new ones were born to face the new environmental changes and human being needs. The comprehensive analysis of collinearity events and selection pressure shows that genome-wide duplication and fragment duplication are the main methods for the expansion of the PEPC family, and they continue to undergo purification selection during the evolutionary process. PEPC genes were widely expressed with temporal and spatial patterns. The expression patterns of PEPC genes were similar in and with a slight difference. PEPC2A and 2D were highly expressed in cotton reproductive tissues, including ovule and fiber at all tested developmental stages in both cultivated cottons. However, PEPC1A and 1D were dominantly expressed in vegetative tissues. Abiotic stress also induced the aberrant expression of PEPC genes, in which PEPC1 was induced by both chilling and salinity stresses while PEPC5 was induced by chilling and drought stresses. Each pair (A and D) of PEPC genes showed the similar response to cotton development and different abiotic stress, suggesting the similar function of these PEPCs no matter their origination from A or D sub-genome. However, some divergence was also observed among their origination, such as PEPC5D was induced but PEPC5A was inhibited in during drought treatment, suggesting that a different organized PEPC gene may evolve different functions during cotton evolution. During cotton polyploidization, the homologues genes may refunction and play different roles in different situations.
磷酸烯醇式丙酮酸羧化酶（PEPC）是植物中的一种重要酶，它通过三羧酸循环调节碳流，并控制蛋白质和油脂的生物合成。尽管它很重要，但对于世界上最重要的纤维作物棉花中的PEPC研究却很少。在本研究中，在15个基因组中总共鉴定出125个PEPC。棉花中的所有PEPC基因被分为六组，每组在每个二倍体棉花中通常包含一个PEPC成员，在每个四倍体棉花中通常包含两个。这表明PEPC基因在棉花分化之前就已经存在。在其他植物物种中存在额外的PEPC亚组，这表明在不同植物进化过程中存在不同的进化和自然选择。PEPC基因在每个棉花亚基因组中独立进化。在棉花驯化和进化过程中，某些PEPC基因丢失，新的基因产生以应对新的环境变化和人类需求。共线性事件和选择压力的综合分析表明，全基因组复制和片段复制是PEPC家族扩张的主要方式，并且它们在进化过程中持续经历纯化选择。PEPC基因以时空模式广泛表达。PEPC基因在陆地棉和海岛棉中的表达模式相似但略有差异。PEPC2A和2D在棉花生殖组织中高表达，包括在两种栽培棉所有测试发育阶段的胚珠和纤维中。然而，PEPC1A和1D主要在营养组织中表达。非生物胁迫也诱导PEPC基因的异常表达，其中PEPC1受到低温和盐胁迫的诱导，而PEPC5受到低温和干旱胁迫的诱导。每对（A和D）PEPC基因对棉花发育和不同非生物胁迫表现出相似的响应，这表明无论这些PEPC基因起源于A或D亚基因组，它们都具有相似的功能。然而，在它们的起源之间也观察到一些差异，例如在干旱处理期间，海岛棉中的PEPC5D被诱导而PEPC5A被抑制，这表明在棉花进化过程中，不同组织的PEPC基因可能进化出不同的功能。在棉花多倍体化过程中，同源基因可能会重新发挥功能并在不同情况下发挥不同作用。
