Abstract：
Vibrio parahaemolyticus possesses two distinct type VI secretion systems (T6SS), namely T6SS1 and T6SS2. T6SS1 is predominantly responsible for adhesion to Caco-2 and HeLa cells and for the antibacterial activity of V. parahaemolyticus, while T6SS2 mainly contributes to HeLa cell adhesion. However, it remains unclear whether the T6SS systems have other physiological roles in V. parahaemolyticus. In this study, we demonstrated that the deletion of icmF2, a structural gene of T6SS2, reduced the biofilm formation capacity of V. parahaemolyticus under low salt conditions, which was also influenced by the incubation time. Nonetheless, the deletion of icmF2 did not affect the biofilm formation capacity in marine-like growth conditions, nor did it impact the flagella-driven swimming and swarming motility of V. parahaemolyticus. IcmF2 was found to promote the production of the main components of the biofilm matrix, including extracellular DNA (eDNA) and extracellular proteins, and cyclic di-GMP (c-di-GMP) in V. parahaemolyticus. Additionally, IcmF2 positively influenced the transcription of cpsA, mfpA, and several genes involved in c-di-GMP metabolism, including scrJ, scrL, vopY, tpdA, gefA, and scrG. Conversely, the transcription of scrA was negatively impacted by IcmF2. Therefore, IcmF2-dependent biofilm formation was mediated through its effects on the production of eDNA, extracellular proteins, and c-di-GMP, as well as its impact on the transcription of cpsA, mfpA, and genes associated with c-di-GMP metabolism. This study confirmed new physiological roles for IcmF2 in promoting biofilm formation and c-di-GMP production in V. parahaemolyticus.
摘要：
副溶血性弧菌具有两种不同的VI型分泌系统（T6SS），即T6SS1和T6SS2。T6SS1主要负责与Caco-2和HeLa细胞的粘附以及副溶血性弧菌的抗菌活性，而T6SS2主要参与HeLa细胞的粘附。然而,目前尚不清楚T6SS系统是否在副溶血性弧菌中具有其他生理作用.在这项研究中,我们证明，在低盐条件下，T6SS2的结构基因icmF2的缺失降低了副溶血性弧菌的生物膜形成能力，这也受到孵化时间的影响。尽管如此，icmF2的缺失不影响在海洋样生长条件下的生物膜形成能力，也不影响副溶血性弧菌鞭毛驱动的游泳和成群运动。发现IcmF2促进生物膜基质主要成分的产生，包括细胞外DNA（eDNA）和细胞外蛋白质，和副溶血性弧菌中的环状di-GMP（c-di-GMP）。此外,IcmF2对cpsA的转录有正向影响，mfpA,和一些参与c-di-GMP代谢的基因，包括scrJ,scrL,vopy,tpdA,GEFA,和scrg。相反，scrA的转录受到IcmF2的负面影响。因此,IcmF2依赖性生物膜的形成是通过其对eDNA产生的影响来介导的，胞外蛋白质，和c-di-GMP,以及它对CPSA转录的影响，mfpA,以及与c-di-GMP代谢相关的基因。这项研究证实了IcmF2在促进副溶血性弧菌中生物膜形成和c-di-GMP产生中的新生理作用。
