[Transcriptomic Analysis of 2 Gene Mutant Strains of CRISPR-Cas9 System].

OBJECTIVE

To explore the differences in transcriptional levels between mutant strains of 2 gene of CRISPR-Cas9 system of ( ) and wild-type strains.

METHODS

The UA159, 2-gene-deleted strains (Δ 2) and 2-gene-covering strains (Δ 2/pDL278- 2) of were cultivated. Total RNA was extracted, and high-throughput sequencing technology was used for transcriptome sequencing. Based on the GO analysis and the KEGG analysis of the differentially expressed genes, the biological processes involved were thoroughly examined. The qRT-PCR method was used to verify the transcriptome sequencing results.

RESULTS

The transcriptome results showed that, compared with UA159, there were 176 genes in Δ 2 whose gene expression changed more than one fold ( <0.05), of which 72 were up-regulated and 104 were down-regulated. The GO enrichment analysis and the KEGG enrichment analysis revealed that both the up-regulated and down-regulated differentially expressed genes (DEG) were involved in amino acid transport and metabolism. In addition, the biological processes that up-regulated DEGs participated in were mainly related to carbohydrate metabolism, energy production and conversion, and transcription; down-regulated DEGs were mainly related to lipid metabolism, DNA replication, recombination and repair, signal transduction mechanisms, nucleotide transport and metabolism. The functions of some DEGs were still unclear. Results of qRT-PCR verified that the expressions of , and (genes related to the formation of branched-chain amino acids) were significantly down-regulated in Δ 2 when compared with UA159 and Δ 2/pDL278- 2.

CONCLUSION

Through transcriptome sequencing and qRT-PCR verification, it was found that the expression of genes related to branched-chain amino acid synthesis and cell membrane permeability in Δ 2 changed significantly.