Lysobacter penaei sp. nov., isolated from intestinal content of a Pacific white shrimp (Penaeus vannamei)

An Update on Novel Taxa and Revised Taxonomic Status of Bacteria (Including Members of the Phylum Planctomycetota) Isolated from Aquatic Host Species Described in 2018 to 2021

Increased interest in farmed aquatic species, aquatic conservation measures, and microbial metabolic end-product utilization have translated into a need for awareness and recognition of novel microbial species and revisions to bacterial taxonomy. Because this need has largely been unmet, through a 4-year literature review, we present lists of novel and revised bacterial species (including members of the phylum Planctomycetota) derived from aquatic hosts that can serve as a baseline for future biennial summaries of taxonomic revisions in this field. Most new and revised taxa were noted within oxidase-positive and/or nonglucose fermentative Gram-negative bacilli, including members of the Tenacibaculum, Flavobacterium, and Vibrio genera. Valid and effectively published novel members of the Streptococcus, Erysipelothrix, and Photobacterium genera are additionally described from disease pathogenesis perspectives.

Parvicella tangerina gen. nov., sp. nov. (Parvicellaceae fam. nov., Flavobacteriales), first cultured representative of the marine clade UBA10066, and Lysobacter luteus sp. nov., from activated sludge of a seawater-processing wastewater treatment plant

Two strains isolated from a sample of activated sludge that was obtained from a seawater-based wastewater treatment plant on the southeastern Mediterranean coast of Spain have been characterized to achieve their taxonomic classification, since preliminary data suggested they could represent novel taxa. Given the uniqueness of this habitat, as this sort of plants are rare in the world and this one used seawater to process an influent containing intermediate products from amoxicillin synthesis, we also explored their ecology and the annotations of their genomic sequences. Analysis of their 16S rRNA gene sequences revealed that one of them, which was orange-pigmented, was distantly related to Vicingus serpentipes (family Vicingaceae ) and to other representatives of neighbouring families in the order Flavobacteriales (class Flavobacteriia ) by 88–89 % similarities; while the other strain, which was yellow-pigmented, was a putative new species of Lysobacter (family Xanthomonadaceae , order Xanthomonadales , class Gammaproteobacteria ) with Lysobacter arseniciresistens as closest relative (97.3 % 16S rRNA sequence similarity to its type strain). Following a polyphasic taxonomic approach, including a genome-based phylogenetic analysis and a thorough phenotypic characterization, we propose the following novel taxa: Parvicella tangerina gen. nov., sp. nov. (whose type strain is AS29M-1T=CECT 30217T=LMG 32344T), Parvicellaceae fam. nov. (whose type genus is Parvicella), and Lysobacter luteus sp. nov. (whose type strain is AS29MT=CECT 30171T=LMG 32343T).

Shewanella jiangmenensis sp. nov., isolated from aquaculture water

A Gram-stain-negative and facultatively anaerobic bacterial strain designated as JM162201^T was isolated from aquaculture water for farming Pacific white shrimp (Litopenaeus vannamei). The genome size of strain JM162201^T was 4,436,316 bp, and the genomic DNA G + C content was 55.0%. Phylogenetic analysis based on 16S rRNA gene sequences and genomes showed that strain JM162201^T belonged to the genus Shewanella and was closely related to Shewanella litorisediminis SMK1-12^T (97.1%), Shewanella khirikhana TH2012^T (97.0%), and Shewanella amazonensis SB2B^T (96.0%). The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain JM162201^T and three reference type strains were below the recognized thresholds of 95.0-96.0% (for ANI) and 70.0% (for dDDH) for species delineation. Growth occurred at 10-40 °C (optimum, 30 °C), at pH 4.0-10.0 (optimum, 7.0-8.0), and in 0-6.0% NaCl (w/v, optimum, 0-0.1%). The major cellular fatty acids of strain JM162201^T were summed feature 3 (C_16:1 ω7c and/or C_16:1 ω6c), C_17:1 ω8c, iso-C_15:0, C_16:0, and C_15:0. The predominant quinones were MK7, Q-7, and Q-8. The major polar lipids were phosphatidylethanolamine (PE) and phosphatidylglycerol (PG). Based on the polyphasic taxonomical analyses, strain JM162201^T represents a novel species of the genus Shewanella, for which the name Shewanella jiangmenensis sp. nov. is proposed, with the type strain JM162201^T (= GDMCC 1.2006^T = KCTC 82340^T).

Bacteria Associated With Phaeocystis globosa and Their Influence on Colony Formation

Phaeocystis globosa (P. globosa) is one of the dominant algae during harmful algal blooms (HABs) in coastal regions of Southern China. P. globosa exhibits complex heteromorphic life cycles that could switch between solitary cells and colonies. The ecological success of P. globosa has been attributed to its colony formation, although underlying mechanisms remain unknown. Here, we investigated different bacterial communities associated with P. globosa colonies and their influence on colony formation of two P. globosa strains isolated from coastal waters of Guangxi (GX) and Shantou (ST). Eight operational taxonomic units (OTUs) were observed in ST co-cultures and were identified as biomarkers based on Linear discriminant analysis Effect Size (LEfSe) analysis, while seven biomarkers were identified in P. globosa GX co-cultures. Bacterial communities associated with the P. globosa GX were more diverse than those of the ST strain. The most dominant phylum in the two co-cultures was Proteobacteria, within which Marinobacter was the most abundant genus in both GX and ST co-cultures. Bacteroidota were only observed in the GX co-cultures and Planctomycetota were only observed in the ST co-cultures. Co-culture experiments revealed that P. globosa colony formation was not influenced by low and medium cell densities of Marinobacter sp. GS7, but was inhibited by high cell densities of Marinobacter sp. GS7. Overall, these results indicated that the associated bacteria are selected by different P. globosa strains, which may affect the colony formation and development of P. globosa.