Vibrio alginolyticus, a Gram-negative halophilic zoonotic pathogen, can cause bacterial hemorrhagic septicemia in various aquaculture species and wound infections in humans. V. alginolyticus brings about huge economic losses in aquaculture all around the world. Hfq, a ubiquitous RNA-binding protein, is a global post-transcriptional regulator in most bacteria and some archaea, by facilitating base-pairing between sRNAs and their mRNA targets, and is essential for adaptation to different environments and growth conditions. Despite its important roles in the stress adaptation, virulence, nutrient utilization, and colony morphology in V. alginolyticus, further research is required to shed light on the pathways modulated by Hfq. In this study, we used metabolomics and lipidomics analytical approaches based on ultrahigh-performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS) to understand the impact of Hfq on the metabolic profile of V. alginolyticus. The deletion of the hfq gene resulted in the growth deficiency and cell elongation of V. alginolyticus cultured in the rich medium. Substantial metabolic alterations, mainly involved in amino acids, nucleotides, fatty acids, and lipids, were observed in the hfq deletion mutant strain (Δhfq) when compared to the wild-type (WT) strain and its complemented strain (hfq⁺). Notably, the hfq deletion induced accumulations of free fatty acids (FFAs) and nucleotides, but decreased levels of most amino acids (e.g., branched amino acids, aromatic amino acids, and aspartate family amino acids). Meanwhile, the majority of lipids (e.g., lysophosphatidylglycerol, lysophosphatidylethanolamine, phosphatidylcholine, phosphatidic acid, cardiolipin, sphingomyelin, some phosphatidylglycerol and phosphatidylethanolamine with mono- or poly-unsaturated fatty acids) were decreased, while ceramide, diacylglycerol, triacylglycerol and some phosphatidylglycerol and phosphatidylethanolamine with saturated fatty acids increased in the Δhfq strain. These data demonstrated that the hfq deletion triggered de novo synthesis of FFAs and nucleosides and enhanced the catabolism of phospholipid and sphingomyelin to further regulate cell division and growth. Additionally, the hfq deletion could inhibit the synthesis of the branched amino acids, aromatic amino acids and enhance the TCA cycle to influence cell stress defenses and energy metabolism. Our research indicates that Hfq can regulate pathways associated with cell division, growth and stress resistance, being an important metabolic modulator in V. alginolyticus.

溶藻弧菌是革兰氏阴性嗜盐人畜共患病原体，可引起多种水产养殖种类的细菌性出血性败血病和人类伤口感染。溶藻弧菌在全世界的水产养殖中造成了巨大的经济损失。Hfq是一种普遍存在的RNA结合蛋白，通过促进sRNA及其mRNA靶标之间的碱基配对，是大多数细菌和某些古细菌中的一种全球转录后调节剂，对于适应不同的环境和生长条件至关重要。尽管在溶藻弧菌中它在胁迫适应，毒力，养分利用和菌落形态方面具有重要作用，，需要进一步研究以阐明由Hfq调控的途径。在这项研究中，我们使用基于超高效液相色谱-高分辨率质谱（UHPLC-HRMS）的代谢组学和脂质组学分析方法来了解Hfq对溶藻弧菌代谢谱的影响。hfq基因的缺失导致在丰富培养基中培养的溶藻弧菌的生长缺陷和细胞伸长。与野生型（WT）菌株及其互补菌株（hfq）相比，在hfq缺失突变株（Δhfq）中观察到大量的代谢变化，主要涉及氨基酸，核苷酸，脂肪酸和脂质。⁺）。值得注意的是，hfq缺失诱导了游离脂肪酸（FFA）和核苷酸的积累，但大多数氨基酸（例如，支链氨基酸，芳族氨基酸和天冬氨酸家族氨基酸）的含量降低。同时，大多数脂质（例如，溶血磷脂酰甘油，溶血磷脂酰乙醇胺，磷脂酰胆碱，磷脂酸，心磷脂，鞘磷脂，一些磷脂酰甘油和磷脂酰乙醇胺以及单或多不饱和酰基磷脂酰甘油三甘油酯和甘油三酸酯甘油三酸酯和甘油三酸酯）Δhfq菌株中饱和脂肪酸的含量增加。这些数据表明，hfq删除从头触发FFA和核苷的合成，并增强磷脂和鞘磷脂的分解代谢，以进一步调节细胞分裂和生长。此外，hfq缺失可以抑制支链氨基酸，芳香族氨基酸的合成，并增强TCA循环，从而影响细胞应激防御和能量代谢。我们的研究表明，Hfq可以调节与细胞分裂，生长和抗逆性相关的途径，是溶藻弧菌的重要代谢调节剂。