Sulfitobacter pseudonitzschiae H46, a marine bacterium associated with microalgae, exhibits algicidal activity against harmful algal bloom microalgae Chattonella marina and Alexandrium tamarense. The complete genome of S. pseudonitzschiae H46 was sequenced to investigate its algicidal mechanism further. One chromosome, eight circular plasmids and add one not circularized plasmid (Plas II) were identified, which are 4.93 Mb in length with 4871 open reading frames. The genome contains 43 transfer RNA (tRNA) genes; six ribosome RNA (rRNA) genes that can be classified into two 5S rRNA, two 16S rRNA, two 23S rRNA, and two small RNA (sRNA) genes. Genomic annotation revealed that S. pseudonitzschiae H46 has two pairs of LuxI/R-type Quorum-sensing (QS) systems. The QS systems can regulate the functions involved in host colonization and biofilm formation. Moreover, the existence of 49 Type-IV and Dddl genes in the chromosome indicated that Dimethylsulfoniopropionate (DMSP) catabolism of S. pseudonitzschiae H46 is the main interaction with marine microalgae. S. pseudonitzschiae H46 utilizes DMSP produced by microalgae as the carbon source, and this may induce algicidal activity. The complete genome sequence of S. pseudonitzschiae H46 can provide useful information on the underlying molecular mechanism between QS and algicidal activity.

Sulfitobacter pseudonitzschiae H46 是一种与微藻相关的海洋细菌，对有害的藻华微藻Chattonella marina和Alexandrium tamarense具有杀藻活性。对S. pseudonitzschiae H46的完整基因组进行了测序，以进一步研究其杀藻机制。鉴定出1条染色体、8条环状质粒和1条未环化质粒（Plas II），全长4.93 Mb，开放阅读框4871个。基因组包含 43 个转移 RNA (tRNA) 基因；六个核糖体 RNA (rRNA) 基因，可分为两个 5S rRNA、两个 16S rRNA、两个 23S rRNA 和两个小 RNA (sRNA) 基因。基因组注释显示S. pseudonitzschiae H46 有两对LuxI/R型群体感应 (QS) 系统。QS 系统可以调节涉及宿主定植和生物膜形成的功能。此外，49型IV和存在Dddl在染色体上的基因表明，二甲基巯基丙酸（DMSP）分解代谢S. pseudonitzschiae H46是与海洋微藻的主要相互作用。S. pseudonitzschiae H46 利用微藻产生的 DMSP 作为碳源，这可能会诱导杀藻活性。S. pseudonitzschiae H46的完整基因组序列可以提供有关 QS 和杀藻活性之间潜在分子机制的有用信息。