Kushneria phosphatilytica sp. nov., a phosphate-solubilizing bacterium isolated from a solar saltern.

A Gram-stain-negative, motile, rod-shaped, non-endospore-forming, aerobic and halophilic bacterium, designated strain YCWA18T, was isolated from the sediment of Jimo-Daqiao saltern in China. This strain was able to grow at NaCl concentrations in the range 0.5-20 % (w/v) with optimum growth at 6 % (w/v) NaCl. Growth occurred at temperatures of 4-40 °C (optimum 28 °C) and pH 4.0-9.0 (optimum 7.0). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain YCWA18T belonged to the genus Kushneria and shared the highest sequence similarity of 98.7 % with Kushneria sinocarnis DSM 23229T. Moreover, the phylogenetic analysis based on the 23S rRNA gene sequence also confirmed the phylogenetic position of this novel strain. The predominant fatty acids were C16 : 0, C17 : 0 cyclo and C12 : 0 3-OH. The major isoprenoid quinone was Q-9 (94.2 %) and the polar lipids were diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), phosphatidylethanolamine (PE), an unidentified aminolipid (AL), an unidentified phospholipids (PL) and two unidentified lipids (L). The complete genome of strain YCWA18T consisted of a single, circular chromosome of 3 624 619 bp, with an average G+C content of 59.1 mol%. A genome-based phylogenetic tree constructed using an up-to-date bacterial core gene set (UBCG) showed that strain YCWA18T formed a clade with K. sinocarnis DSM 23229T. However, the level of the ANI and dDDH values between strain YCWA18T and K. sinocarnis DSM 23229T were 82.3 and 24.6 %, respectively, which were low enough to distinguish strain YCWA18T from K. sinocarnis DSM 23229T. Overall, based on the phenotypic, chemotaxonomic, phylogenetic and genomic analyses, strain YCWA18T represents a novel species of genus Kushneria. The name Kushneria phosphatilytica sp. nov. is proposed, with the type strain YCWA18T (=CGMCC 1.9149T=NCCB 100306T).

Complete genome sequence of Kushneria phosphatilytica YCWA18T reveals the P-solubilizing activity of the genus Kushneria.

Kushneria phosphatilytica YCWA18T (= CGMCC 1.9149T = NCCB 100306T) was isolated from sediment collected in a saltern on the eastern coast of Yellow Sea in China. The genome was sequenced and comprised of one circular chromosome with the size of 3,624,619 bp and DNA G + C content of 59.13%. A total of 3267 protein-coding genes, 64 tRNA genes and 12 rRNA genes were obtained. Genomic annotation indicated that the genome of K. phosphatilytica YCWA18T had 34 genes involved in phosphorus (P) solubilization/metabolism, e.g., gdh, pqq, phoA, phoD and phoX, which products can convert insoluble P-containing compounds to more bio-available dissolved inorganic P. Comparative genomic analysis of Kushneria strains revealed that gdh, pqq, phoA, phoD and phoX were widely distributed in these strains, indicating the genus Kushneria may play an important role in the P cycle. Additionally, a multitude of salt tolerance genes were detected in the genome of K. phosphatilytica YCWA18T. This study and the genome sequence data will be available for further research and will provide insights into potential biotechnological and agricultural applications of Kushneria strains.

Bibliometrics and visualization analysis of EwE model based on CiteSpace.

To explore the historical evolution and current status of the EwE (Ecopath with Ecosim) modelling research, the core dataset and extended dataset were collected by topic retrieval and citation indexing methods from the "Web of Science" from 1984 to 2020. The bibliometric analysis and mapping knowledge were performed by CiteSpace software, focusing on literature distribution, research forces, research theme, and hotspot evolution. The results showed that the annual publications in the EwE model researches were increasing, covering multi-disciplinary fields. Christensen, Walters, and Pauly were representative scholars with an important role in model development and relevant international cooperation. In the early stage, EwE model was usually applied to solve ecosystem problems, including spatial-temporal dynamic of structure and function, and the ecosystem effects of fisheries. Currently, marine resource management, ecosystem modelling, marine protected areas and ecosystem indicators had become the key themes. The research hotspots shifted from model development and food web structure to ecosystem forecasting and resource management, which would provide scientific evidence for ecosystem-based aquatic resource management and the construction of protected area in marine.