Marine phycosphere hosts cross-kingdom algae-bacteria interactions playing a variety of crucial roles in aquatic ecosystems especially for the prevention and control of harmful algal blooms (HABs). During the investigation of structural composition of phycosphere microbiota (PM) of diverse marine HAB dinoflagellates, a Gram-negative, strictly aerobic, non-motile and rod-shaped bacterium designated LZ-17^T was isolated from the phycosphere of highly toxic Alexandrium catenella LZT09. The 16S rRNA gene sequence analysis and the multilocus sequence analysis (MLSA) based on five protein-coding housekeeping genes (atpD, gyrB, mutL, topA and rpoD) indicated that strain LZ-17^T was affiliated to the genus Maritimibacter within the family Rhodobacteraceae, and closely related to Maritimibacter alkaliphilus HTCC2654^T (99.1%), ‘Maritimibacter harenae’ DP07^T (97.9%) and M. lacisalsi X12M-4^T (95.7%). The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain LZ-17^T and the type strain of M. alkaliphilus were 96.9% and 74.7%. However, strain LZ-17^T could be clearly distinguished from its closest by the phenotypical and phenotypical characteristics. Strain LZ-17^T contained Q-10 as its major isoprenoid quinone, and summed feature 8 (C_18:1 ω7c and/or C_18:1 ω6c), C_16:0 and C_16:0 2-OH as the predominant fatty acids (>10%). The major polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol and phosphatidylcholine. The DNA G + C content was 64.3 mol%. Based on the polyphasic taxonomic characterization, strain LZ-17^T represents a novel species of the genus Maritimibacter, for which the name Maritimibacter alexandrii sp. nov. is proposed, with the type strain LZ-17^T (=CCTCC 2019005^T = KCTC 72193^T).

海洋生态圈承载着跨界藻类-细菌的相互作用，在水生生态系统中发挥着各种关键作用，尤其是在预防和控制有害藻华 (HAB) 方面。在研究不同海洋 HAB 鞭毛藻的藻圈微生物群 (PM) 的结构组成期间，从剧毒的链状亚历山大藻LZT09的藻圈中分离出一种革兰氏阴性、严格需氧、非运动性和杆状细菌 LZ-17 ^T . 基于5个蛋白质编码看家基因（atp D、gyr B、mut L、top A和rpo）的16S rRNA基因序列分析和多位点序列分析（MLSA）D) 表明菌株 LZ-17 ^T隶属于红杆菌科Maritimibacter属，与Maritimibacter basephilus HTCC2654 ^T (99.1%)、' Maritimibacter harenae ' DP07 ^T (97.9%) 和M. lacisalsi4- M.X12M密切相关^T (95.7%)。菌株 LZ-17 ^T与嗜碱 M.典型菌株之间的平均核苷酸同一性 (ANI) 和数字 DNA-DNA 杂交 (dDDH) 值分别为 96.9% 和 74.7%。然而，菌株 LZ-17 ^T可以通过表型和表型特征清楚地将其与其最接近的区分开来。菌株 LZ-17 ^T含有 Q-10 作为其主要的类异戊二烯醌，并将特征 8（C _18:1 ω 7c 和/或 C _18:1 ω 6c）、C _16:0和 C _16:0 2-OH总结为主要脂肪酸 (>10%)。主要的极性脂质由二磷脂酰甘油、磷脂酰甘油和磷脂酰胆碱组成。DNA G + C 含量为 64.3 mol%。基于多相分类学特征，菌株 LZ-17 ^T代表Maritimibacter属的一个新物种，其名称Maritimibacter alexandriisp. 十一月 提出，具有类型应变 LZ-17 ^T (= CCTCC 2019005 ^T  = KCTC 72193 ^T )。