Alteromonas is a widely distributed genus of marine Gammaproteobacteria, with representatives shown to be key players in diverse processes, including biogeochemical cycling and biofouling of marine substrata. While Alteromonas spp. are early colonizers of copper-based antifouling paints on marine vessels, their mechanism of tolerance is poorly understood. PacBio whole-genome sequencing of Alteromonas macleodii strains CUKW and KCC02, isolated from Cu/Ni alloy test coupons submerged in oligotrophic coastal waters, indicated the presence of multiple megaplasmids (ca. 200 kb) in both. A pulsed-field gel electrophoresis method was developed and used to confirm the presence of multiple megaplasmids in these two strains; it was then used to screen additional Alteromonas strains for which little to no sequencing data exist. Plasmids were not detected in any of the other strains. Bioinformatic analysis of the CUKW and KCC02 plasmids identified numerous genes associated with metal resistance. Copper resistance orthologs from both the Escherichia coli Cue and Cus and Pseudomonas syringae Cop systems were present, at times as multiple copies. Metal growth assays in the presence of copper, cobalt, manganese, and zinc performed with 10 Alteromonas strains demonstrated the ability of CUKW and KCC02 to grow at metal concentrations inhibitory to all the other strains tested. This study reports multiple megaplasmids in Alteromonas strains. Bioinformatic analysis of the CUKW and KCC02 plasmids indicate that they harbor elements of the Tra system conjugation apparatus, although their type of mobility remains to be experimentally verified.

IMPORTANCE Copper is commonly used as an antifouling agent on ship hulls. Alteromonas spp. are early colonizers of copper-based antifouling paint, but their mechanism of tolerance is poorly understood. Sequencing of A. macleodii strains isolated from copper test materials for marine ships indicated the presence of multiple megaplasmids. Plasmids serve as key vectors in horizontal gene transfer and confer traits such as metal resistance, detoxification, ecological interaction, and antibiotic resistance. Bioinformatic analysis identified many metal resistance genes and genes associated with mobility. Understanding the molecular mechanisms and capacity for gene transfer within marine biofilms provides a platform for the development of novel antifouling solutions targeting genes involved in copper tolerance and biofilm formation.

变形单胞菌是海洋γ-变形杆菌的一种广泛分布的物种，其代表被证明是包括生物地球化学循环和海洋基质生物污染在内的各种过程的关键参与者。而Alteromonas spp。作为早期在船舶上使用的铜基防污涂料的定植剂，人们对其耐受性的机理了解甚少。斑纹链霉菌的PacBio全基因组测序从淹没在富营养化沿海水域中的Cu / Ni合金试样中分离出的CUKW和KCC02菌株表明这两种菌株均存在多个大质粒（约200 kb）。开发了脉冲场凝胶电泳方法，并用于证实这两个菌株中存在多个大质粒。然后将其用于筛选几乎没有测序数据的其他Alteromonas菌株。在任何其他菌株中均未检测到质粒。CUKW和KCC02质粒的生物信息学分析确定了许多与金属抗性相关的基因。大肠杆菌Cue和Cus和丁香假单胞菌的铜抗性直系同源物缔约方会议系统存在，有时是多个副本。用10个Alteromonas菌株进行的在铜，钴，锰和锌存在下的金属生长试验证明CUKW和KCC02在抑制所有其他待测菌株的金属浓度下生长的能力。这项研究报告了Alteromonas菌株中的多个大质粒。CUKW和KCC02质粒的生物信息学分析表明，尽管它们的迁移类型仍有待实验验证，但它们包含Tra系统结合装置的元件。

重要事项铜通常用作船体的防污剂。链格孢属 它们是铜基防污漆的早期定植剂，但对它们的耐受机理知之甚少。Macleodii的测序从船用铜测试材料中分离出的菌株表明存在多个大质粒。质粒充当水平基因转移的关键载体，并赋予诸如金属抗性，排毒，生态相互作用和抗生素抗性等特征。生物信息学分析确定了许多金属抗性基因和与迁移相关的基因。了解海洋生物膜内基因转移的分子机制和能力为针对涉及铜耐受性和生物膜形成的基因的新型防污解决方案的开发提供了平台。