Marinobacter shengliensis subsp. alexandrii Subsp. Nov., Isolated from Cultivable Phycosphere Microbiota of Highly Toxic Dinoflagellate Alexandrium catenella LZT09 and Description of Marinobacter shengliensis Subsp. shengliensis Subsp. Nov

Abstract

Phycosphere hosts the boundary of unique holobionts harboring dynamic algae-bacteria interactions. During our investigating the microbial consortia composition of phycosphere microbiota (PM) derived from diverse harmful algal blooms (HAB) dinoflagellates, a novel rod-shaped, motile and faint yellow-pigmented bacterium, designated as strain LZ-6 \xa0T , was isolated from HAB Alexandrium catenella LZT09 which produces high levels paralytic shellfish poisoning toxins. Phylogenetic analysis based on 16S rRNA gene and two housekeeping genes, rpo A and phe S sequences showed that the novel isolate\xa0shared the highest gene similarity with Marinobacter shengliensis CGMCC 1.12758 \xa0T (99.6%) with the similarity values of 99.6%, 99.9% and 98.5%, respectively. Further phylogenomic calculations of average nucleotide identity (ANI), average amino acid identity (AAI) and digital DNA-DNA hybridization (dDDH) values between strains LZ-6 \xa0T and the type strain of M. shengliensis were 95.9%, 96.4% and 68.5%, respectively. However, combined phenotypic and chemotaxonomic characterizations revealed that the new isolate was obviously different from the type strain of M. shengliensis . The obtained taxonomic evidences supported that strain LZ-6 \xa0T represents a novel subspecies of M. shengliensis , for which the name is proposed, Marinobacter shengliensis subsp. alexandrii subsp. nov. with the type strain LZ-6 \xa0T (=\u2009CCTCC AB 2018388T T \u2009=\u2009KCTC 72197 \xa0T ). This proposal automatically creates Marinobacter shengliensis subsp. s hengliensis for which the type strain is SL013A34A2 T (=\u2009LMG 27740 \xa0T \u2009=\u2009CGMCC 1.12758 \xa0T ).