Kocuria kristinae, one of the dominant strains in Kedong sufu, can generate γ-aminobutyric acid (GABA). NaCl and ethanol are added to sufu for preservation. This study aims to reveal the effects of NaCl and ethanol stresses on GABA synthesis in K. kristinae. The results suggested that high GABA production was obtained by adding 6% NaCl at the mid-exponential growth phase and 3% ethanol at the late exponential growth phase. Two GABA synthesis pathways were observed, including a new GABA synthesis pathway. Under NaCl stress, genes were upregulated by 1.46- to 3.67-fold in two synthesis pathways of GABA. Under ethanol stress, genes were upregulated by 1.20- to 6.39-fold in two synthesis pathways of GABA, except for speG and MAO. However, their corresponding metabolites were downregulated by 1.02- to 7.69-fold. The changes in genes and metabolites in the carbohydrate and amino acid metabolism pathways and in membrane transport suggested that different metabolic strategies were used to cope with NaCl and ethanol stresses in K. kristinae. The molecular mechanism in improving the production of GABA by NaCl and ethanol stresses was shown in K. kristinae. This study provides a theoretical basis for the development of GABA-enriched sufu by NaCl and ethanol stresses.

Kocuria kristinae，在克东县腐乳优势菌株之一，可以产生γ氨基丁酸（GABA）。将NaCl和乙醇添加到sufu中进行保存。这项研究的目的是揭示NaCl和乙醇胁迫对Kristinae的GABA合成的影响。结果表明，通过在指数增长中期添加6％NaCl，在指数增长后期添加3％乙醇，可以实现高GABA产量。观察到两个GABA合成途径，包括新的GABA合成途径。在NaCl胁迫下，基因在GABA的两种合成途径中上调了1.46至3.67倍。在乙醇胁迫下，除speG和MAO外，GABA的两个合成途径中的基因上调了1.20至6.39倍。但是，它们相应的代谢产物下调了1.02倍至7.69倍。碳水化合物和氨基酸代谢途径以及膜转运中基因和代谢物的变化表明，不同的代谢策略被用来应对Kristinae的NaCl和乙醇胁迫。在K. kristinae中发现了NaCl和乙醇胁迫提高GABA产生的分子机制。该研究为NaCl和乙醇胁迫下富集GABA的sufu的发展提供了理论基础。