Transcriptome analysis reveals the response mechanism of Kocuria rhizophila DC2201 to clindamycin hydrochloride

Abstract:

[Objective] To mine the differentially expressed genes (DEGs) of Kocuria rhizophila DC2201 exposed to clindamycin hydrochloride at 0.5 minimum inhibitory concentration (MIC) and reveal the response mechanism of Kocuria rhizophila DC2201 to clindamycin hydrochloride. [Methods] With the Kocuria rhizophila DC2201 cells cultured in LB liquid medium as the control, Illumina HiSeq platform was used for paired-end sequencing to determine the gene expression of Kocuria rhizophila DC2201 cells exposed to clindamycin hydrochloride at 0.5 MIC. Real-time fluorescence quantitative PCR was then conducted for validation. [Results] A total of 1 202 significantly DEGs were screened out from Kocuria rhizophila DC2201 under the stress of clindamycin hydrochloride, including 604 significantly up-regulated genes and 598 significantly down-regulated genes. After gene ontology (GO) annotation, 1 041 significantly DEGs were annotated into 35 GO terms of molecular function (MF), cell composition (CC), and biological process (BP). The Kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis predicted 16 significantly DEGs related to DNA repair, 43 significantly DEGs related to ribosomal synthesis, 28 DEGs associated with ATP-binding cassette (ABC) transporters, 77 significantly DEGs associated with the pentose phosphate pathway, glycolysis, tricarboxylic acid (TCA) cycle, starch and sucrose, pyruvate, butyrate and other carbohydrate metabolisms, and 5 significantly DEGs related to peptidoglycan synthesis. [Conclusion] Kocuria rhizophila DC2201 exposed to clindamycin hydrochloride adopts a global response mechanism. It increases the efflux of clindamycin hydrochloride by up-regulating the gene expression of major facilitator superfamily (MFS) transporters in the multidrug resistance (MDR) family. By enhancing DNA repair and RNA metabolism pathways, the strain ensures the genomic stability and normal RNA function. In addition, it enhances the ribosome synthesis pathway to compensate for the protein synthesis barrier caused by the binding of clindamycin hydrochloride with the 50S ribosome. Furthermore, the strain reduces the absorption and transportation of carbohydrates to restrain the energy metabolisms pathways, thus slowing down the growth and reducing the energy demand. Correspondingly, the cell wall stability of Kocuria rhizophila DC2201 is also affected.

Key words:Kocuria rhizophila DC2201;clindamycin hydrochloride;transcriptome;response mechanism