许多革兰氏阴性菌的VI型分泌系统(T6SS)将毒性效应子注入相邻细胞,以在发病过程中操纵宿主细胞或杀死竞争性细菌。然而,T6SS效应器的识别和功能仅部分已知。泛欧anatis,革兰氏阴性细菌,常见于各种植物和自然环境中,包括水和土壤。在目前的研究中,在玉米上引起褐色茎腐烂的P.ananatisDZ-12的基因组分析表明,它携带三个T6SS基因簇,即,T6SS-1、T6SS-2和T6SS-3。有趣的是,只有T6SS-1分泌系统参与致病性和细菌竞争。该研究还详细研究了T6SS-1系统,并通过使用包含DUF2169保守结构域的上游T6SS效应子伴侣TecG鉴定了未知的T6SS-1分泌的效应子TseG。TseG可以直接与伴侣TecG相互作用以进行递送,并与下游免疫蛋白TsiG相互作用以防止其毒性。TseG,在泛菌属中高度保守,与玉米的毒力有关,马铃薯,还有洋葱.此外,ananatis使用TseG靶向大肠杆菌,获得竞争优势。本研究首次报道了来自抗假单胞菌的T6SS-1分泌效应子,从而丰富了我们对VI型效应蛋白的各种类型和功能的理解。
The type VI secretion system (T6SS) of many gram-negative bacteria injects toxic effectors into adjacent cells to manipulate host cells during pathogenesis or to kill competing bacteria. However, the identification and function of the T6SS effectors remains only partly known. Pantoea ananatis, a gram-negative bacterium, is commonly found in various plants and natural environments, including water and soil. In the current study, genomic analysis of P. ananatis DZ-12 causing brown stalk rot on maize demonstrated that it carries three T6SS gene clusters, namely, T6SS-1, T6SS-2, and T6SS-3. Interestingly, only T6SS-1 secretion systems are involved in pathogenicity and bacterial competition. The study also investigated the T6SS-1 system in detail and identified an unknown T6SS-1-secreted effector TseG by using the upstream T6SS effector
chaperone TecG containing a conserved domain of DUF2169. TseG can directly interact with the
chaperone TecG for delivery and with a downstream immunity protein TsiG for protection from its toxicity. TseG, highly conserved in the Pantoea genus, is involved in virulence in maize, potato, and onion. Additionally, P. ananatis uses TseG to target Escherichia coli, gaining a competitive advantage. This study provides the first report on the T6SS-1-secreted effector from P. ananatis, thereby enriching our understanding of the various types and functions of type VI effector proteins.