Marine Fishery Research Institute of Zhejiang Province, Zhoushan, 316021, China.
Zhoushan Fishery Environments and Aquatic Products Quality Monitoring Center of Ministry of Agriculture China, Zhoushan, 316021, China.
Sci Rep. 2020 Sep 23;10(1):15479. doi: 10.1038/s41598-020-72484-8.
The gram-negative, aerobic, rod-shaped bacterium Aeromonas hydrophila, the causative agent of motile aeromonad septicaemia, has attracted increasing attention due to its high pathogenicity. Here, we constructed the complete genome sequence of a virulent strain, A. hydrophila HX-3 isolated from Pseudosciaena crocea and performed comparative genomics to investigate its virulence factors and quorum sensing features in comparison with those of other Aeromonas isolates. HX-3 has a circular chromosome of 4,941,513 bp with a 61.0% G + C content encoding 4483 genes, including 4318 protein-coding genes, and 31 rRNA, 127 tRNA and 7 ncRNA operons. Seventy interspersed repeat and 153 tandem repeat sequences, 7 transposons, 8 clustered regularly interspaced short palindromic repeats, and 39 genomic islands were predicted in the A. hydrophila HX-3 genome. Phylogeny and pan-genome were also analyzed herein to confirm the evolutionary relationships on the basis of comparisons with other fully sequenced Aeromonas genomes. In addition, the assembled HX-3 genome was successfully annotated against the Cluster of Orthologous Groups of proteins database (76.03%), Gene Ontology database (18.13%), and Kyoto Encyclopedia of Genes and Genome pathway database (59.68%). Two-component regulatory systems in the HX-3 genome and virulence factors profiles through comparative analysis were predicted, providing insights into pathogenicity. A large number of genes related to the AHL-type 1 (ahyI, ahyR), LuxS-type 2 (luxS, pfs, metEHK, litR, luxOQU) and QseBC-type 3 (qseB, qseC) autoinducer systems were also identified. As a result of the expression of the ahyI gene in Escherichia coli BL21 (DE3), combined UPLC-MS/MS profiling led to the identification of several new N-acyl-homoserine lactone compounds synthesized by AhyI. This genomic analysis determined the comprehensive QS systems of A. hydrophila, which might provide novel information regarding the mechanisms of virulence signatures correlated with QS.
革兰氏阴性需氧杆状菌嗜水气单胞菌是一种运动性气单胞菌败血症的病原体，由于其高致病性而受到越来越多的关注。在这里，我们构建了一株来自拟穴青蟹的毒力株嗜水气单胞菌 HX-3 的全基因组序列，并进行了比较基因组学分析，以研究其与其他气单胞菌分离株相比的毒力因子和群体感应特征。HX-3 具有一个 4941513bp 的圆形染色体，GC 含量为 61.0%，编码 4483 个基因，包括 4318 个蛋白质编码基因，以及 31 个 rRNA、127 个 tRNA 和 7 个非编码 RNA 操纵子。在 A. hydrophila HX-3 基因组中预测了 70 个散布重复序列和 153 个串联重复序列、7 个转座子、8 个成簇规则间隔短回文重复序列和 39 个基因组岛。本文还进行了系统发育和泛基因组分析，以在与其他完全测序的气单胞菌基因组比较的基础上确认进化关系。此外，成功地将组装的 HX-3 基因组注释到蛋白质数据库（76.03%）、基因本体数据库（18.13%）和京都基因与基因组百科全书途径数据库（59.68%）中。通过比较分析预测了 HX-3 基因组中的双组分调控系统和毒力因子图谱，为研究致病性提供了线索。还鉴定了大量与 AHL 型 1（ahyI、ahyR）、LuxS 型 2（luxS、pfs、metEHK、litR、luxOQU）和 QseBC 型 3（qseB、qseC）自体诱导物系统相关的基因。由于在大肠杆菌 BL21（DE3）中表达了 ahyI 基因，结合 UPLC-MS/MS 分析，鉴定出了由 AhyI 合成的几种新的 N-酰基高丝氨酸内酯化合物。这项基因组分析确定了嗜水气单胞菌的综合 QS 系统，这可能为与 QS 相关的毒力特征的机制提供新的信息。
