Genomic Analysis of Halotolerant Bacterial Strains Martelella soudanensis NC18^T and NC20

Abstract

Two novel, halotolerant strains of Martelella soudanensis , NC18 T and NC20, were isolated from deep subsurface sediment, deeply sequenced, and comparatively analyzed with related strains. Based on a phylogenetic analysis using 16S rRNA gene sequences, the two strains grouped with members of the genus Martelella . Here, we sequenced the complete genomes of NC18 T and NC20 to understand the mechanisms of their halotolerance. The genome sizes and G+C content of the strains were 6.1 Mb and 61.8 mol%, respectively. Moreover, NC18 T and NC20 were predicted to contain 5,849 and 5,830 genes, and 5,502 and 5,585 protein-coding genes, respectively. Both strains contain the identically predicted 6 rRNAs and 48 tRNAs. The harboring of halotolerant-associated genes revealed that strains NC18 T and NC20 might tolerate high salinity through the accumulation of potassium ions in a “salt-in” strategy induced by K + uptake protein (kup) and the K + transport system (trkAH and kdpFABC). These two strains also use the ectoine transport system (dctPQM), the glycine betaine transport system (proVWX), and glycine betaine uptake protein (opu) to accumulate “compatible solutes,” such as ectoine and glycine betaine, to protect cells from salt stress. This study reveals the halotolerance mechanism of strains NC18 T and NC20 in high salt environments and suggests potential applications for these halotolerant and halophilic strains in environmental biotechnology.

Characterization and the first complete genome sequence of a novel strain of Bergeyella porcorum isolated from pigs in China

“…In addition, average nucleotide identity (ANI) and in silico DNA–DNA hybridization ( is DDH) analyses were performed through the OrthoANIu algorithm ( http://www.ezbiocloud.net/tools/orthoaniu ) and the Genome-to-Genome Distance Calculator 3.0 ( http://ggdc.dsmz.de/ggdc.php ), respectively [ 36 , 37 ]. If the genomic DNA of two organisms reveals a DDH similarity of less than 70% and an ANI similarity of less than 95%, the species are typically considered distinct, and vice versa [ 38 ].…”

Understanding the mechanisms of halotolerance in members of Pontixanthobacter and Allopontixanthobacter by comparative genome analysis

“…The results showed that Nitriliruptoria harbor similar synthesis systems of solutes, such as trehalose, glutamine, glutamate, and proline, and on the other hand each member of Nitriliruptoria species possesses specific mechanisms, K + influx and efflux, betaine and ectoine synthesis, and compatible solutes transport ( Chen et al, 2020 ). Using whole-genome analysis, the halotolerant strains of Martelella soudanensis , NC18 T and NC20, were predicted to harbor various halotolerant-associated genes, including K + uptake protein, K + transport system, ectoine transport system, glycine betaine transport system, and glycine betaine uptake protein, indicating that strains NC18 T and NC20 might tolerate high salinity through the accumulation of potassium ions, ectoine, glycine betaine ( Lee and Kim, 2022 ). Although these findings help to understand the versatile mechanisms of halotolerance existing in halotolerant microbes, genomic comparisons are usually based on genome-wide searches for homologs of known halotolerance-related genes, such as those involved in K + and Na + influx and efflux and the synthesis and transport of compatible solutes.…”