Abstract: Halomonas binhaiensis Y2R2 is a novel species of the genus Halomonas with a phosphate-solubilizing function, which was isolated from Tianjin coastal saline-alkali land. In this paper, the genome function of strain Y2R2 was annotated and compared, and the gene cluster of secondary metabolites synthesis was predicted to explore its potential functions. Functional annotation of GO, COG and KEGG databases of strain Y2R2 showed that there were 341 and 336 genes involved in carbohydrate metabolism and amino acid metabolism, respectively. Comparative genomic analysis between Y2R2 and three closely related model strains showed that there were 3 623 gene families and 663 unique genes, among which the homology with Halomonas huangheensis NTU-107 was the highest. A number of strain Y2R2 secondary metabolite synthesis gene clusters were predicted, including tetrahydropyrimidine and bacterial terpenoid sodorifen. The similarity between tetrahydropyrimidine synthesis gene cluster and that of Methylophaga thalassica was as high as 75%. Through bioinformatics analysis, the mechanism of strain Y2R2 adapting to high osmotic pressure environment and dissolving phosphorus was explored, and the potential function of strain Y2R2 in promoting the growth of saline-alkali plants was explored, which provided support for the application of novel species Y2R2 of Halomonas in coastal saline-alkali land improvement.

Key words: Halomonas, phosphate-solubilizing bacteria, functional annotation, gene function mining, secondary metabolites