Institute of Science, Nirma University, Sarkhej-Gandhinagar Highway, Ahmedabad, Gujarat, 382481, India.
World J Microbiol Biotechnol. 2019 Aug 26;35(9):140. doi: 10.1007/s11274-019-2717-7.
Pseudomonas species are the most versatile of all known bacteria for metabolic flexibility and the extent of host range from plants to humans that remains unmatched. The evolution of diverse metabolic strategies in these species to adapt to the fluctuating environment guarantees high fitness as well as the ability to withstand stress at multiple levels. These abilities in Pseudomonas species are imprinted by an adaptable genetic repertoire through the integration of external and internal signals via complex regulatory networks. One of the main regulatory networks that lead to optimal growth, survival and cellular robustness is the phenomenon of carbon catabolite repression (CCR). Even though a large array of information is available, the molecular machinery and the mechanism of CCR in Pseudomonas are distinctly diverse from Escherichia coli and Bacillus subtilis. In Pseudomonas, the Crc and Hfq proteins, CbrAB two-component systems and the CrcZ/CrcY small RNA are key components of CCR. The main focus of this review is to elucidate the mechanism of CCR and the accessories involved in regulation of preferred carbon source utilisation over non-preferred ones and how CCR influences the virulence, antibiotic resistance, bioremediation and plant growth promotion pathways. Furthermore, we have also tried to shed some light on the "omics" approaches which can provide deep mechanistic insights into the regulation of CCR. Understanding the mechanistic picture of key regulatory entities and mechanism responsible for metabolic flexibility will create opportunities for exploitation of these versatile prokaryotes in several biotechnological processes.
假单胞菌是所有已知细菌中代谢灵活性和宿主范围最广泛的细菌，从植物到人类，这一范围是无与伦比的。这些物种中多样化代谢策略的进化，使其能够适应不断变化的环境，从而保证了高适应性和在多个层面承受压力的能力。假单胞菌的这些能力通过适应性遗传库通过复杂的调控网络整合内外信号来实现。导致最佳生长、生存和细胞健壮性的主要调控网络之一是碳分解代谢物抑制（CCR）现象。尽管有大量信息可用，但假单胞菌中的分子机制和 CCR 机制与大肠杆菌和枯草芽孢杆菌明显不同。在假单胞菌中，Crc 和 Hfq 蛋白、CbrAB 双组分系统和 CrcZ/CrcY 小 RNA 是 CCR 的关键组成部分。本综述的主要重点是阐明 CCR 的机制以及参与调节优先碳源利用而非非优先碳源的调节因子，以及 CCR 如何影响毒力、抗生素耐药性、生物修复和植物生长促进途径。此外，我们还试图阐明“组学”方法可以为 CCR 的调控提供深入的机制见解。理解关键调节实体和负责代谢灵活性的机制的机制将为在几种生物技术过程中利用这些多功能原核生物创造机会。
