Long-read sequencing of highly copper tolerant Alteromonas macleodii strains reveals the presence of multiple mega-plasmids

An Alteromonas macleodii isolate (CUKW_PB) was obtained from copper coupons suspended in surface seawater in Key West, FL, and maintained in the lab for over 1 year in Burkholder's B Artificial Seawater medium. A mutant was created from the original isolate through successive transfers in Burkholder's B supplemented with 3 mM copper sulfate. The copper-adapted mutant was maintained in 3 mM copper sulfate for over 1 year. Whole-genome sequencing was performed with Paci?c Biosciences (PacBio) RS II sequencing technology.