Abstract: To uncover novel unknown genes relevance during salt stress in Halomonas and to clarify their functions, in this study, the wild strain Halomonas campaniensis strain XH26 was used as the target. The novel geneorf03282(300 bp) up-regulated in expression was screened by salt gradient transcriptomics data and was analyzed for gene sequence, protein physicochemical properties, transmembrane structural domains and secondary structure using bioinformatics tools. Initial exploration of relevant functions through cloning of target genes and construction of heterologous expression vectors. The results showed that the expression of geneorf03282tended to be up-regulated with increasing salinity. Among the genus Halomonas, the gene sequence oforf03282was evolutionarily conserved and showed the highest similarity with strains H.campaniensis LS21 and H.alkaliphila X3, with 99.67% and 99.33%, respectively. The predicted protein Orf03282 was an unstable hydrophobic single transmembrane protein localized to the outer cell membrane. The protein Orf03282 was heterologously expressed in E.coil BL21 and could increase the intracellular Ca2+ content of E.coil BL21 and enhance the salt tolerance of the strain. Therefore, the physiological function of protein Orf03282 might be related to Ca2+ ion transport, increasing the salt tolerance of cells by increasing the intracellular Ca2+ concentration.

Key words: Halomonas campaniensis, hypothetical protein, bioinformatics analysis, functional annotation, salt resistance verification