| 摘要: |
| 【目的】探讨转录因子RpoN和NtrC对变栖克雷伯氏菌菌株DX120E氮代谢和生物学特性的影响，为该菌株在生物固氮领域的广泛应用奠定基础。【方法】在DX120EΔrpoN突变株基础上，利用同源重组技术构建DX120EΔrpoNΔntrC双突变株，并对其进行鉴定。对DX120E野生型菌株、ΔrpoN突变株和ΔrpoNΔntrC双突变株的生长特性、运动能力、胞外多糖产量、生物膜形成及氨基酸代谢能力等进行比较分析。【结果】成功构建了DX120EΔrpoNΔntrC双突变株。与DX120E野生型菌株相比，DX120EΔrpoNΔntrC双突变株在以蛋白胨和尿素为氮源的培养基上生长无明显差异，但在以硝酸钾为唯一氮源的培养基中无法正常生长，DX120EΔrpoNΔntrC双突变株的硝酸盐利用能力、群集能力、胞外多糖产量和生物膜形成能力均有所减弱；DX120EΔrpoN突变株不能利用组氨酸，DX120EΔrpoNΔntrC双突变株可以利用组氨酸，但不能利用脯氨酸；DX120EΔrpoN突变株和DX120EΔrpoNΔntrC双突变株在生长特性、泳动和群集、生物膜形成及胁迫耐受能力等方面无明显差异。【结论】RpoN和NtrC影响菌株DX120E的硝酸盐利用能力、群集能力、胞外多糖产量及生物膜形成能力，RpoN对DX120E的生物学特性调控占主导地位，RpoN和NtrC共同参与调控细菌对氨基酸的摄取及利用。 |
| 关键词: 变栖克雷伯氏菌 RpoN NtrC 基因敲除 |
| DOI：10.13207/j.cnki.jnwafu.2025.02.014 |
| 分类号: |
| 基金项目:国家自然科学基金项目（32360535，31971858） |
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| Mechanism of RpoN and NtrC in Klebsiella variicola strain DX120E |
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HUANG Ying1, SUN Anni1, PAN Yangfei1, YAN Jiawei1, WANG Yuyi1, LI Yangrui1,2, XING Yongxiu1
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1.College of Agriculture,Guangxi University,Nanning,Guangxi 530004,China;2.Guangxi Key Laboratory of Sugarcane Genetic Improvement,Sugarcane Research Institute of Guangxi Academy of Agricultural Sciences,Sugarcane Research Center of Chinese Academy of Agricultural Sciences,Nanning,Guangxi 530007,China
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| Abstract: |
| 【Objective】The study explored the effects of transcription factors RpoN and NtrC on the nitrogen metabolism and biological properties of Klebsiella variicola strain DX120E,and laid the foundation for the wide application of this strain in the field of biological nitrogen fixation.【Method】Based on the DX120EΔrpoN mutant strain,DX120EΔrpoNΔntrC double mutant strain was constructed by homologous recombination technology and identified.The growth characteristics,motility,extracellular polysaccharide production,biofilm formation and amino acid metabolism of wild-type strain,ΔrpoN mutant strain and ΔrpoNΔntrC double mutant strain of DX120E were compared and analyzed.【Result】The DX120EΔrpoNΔntrC double mutant was successfully constructed.Compared with the DX120E wild-type strain,the DX120E ΔrpoN ΔntrC double mutant had no significant difference in growth in medium with peptone and urea as nitrogen source,but could not grow normally in medium with potassium nitrate as the only nitrogen source.The nitrate utilization ability, swarming ability,extracellular polysaccharide production and biofilm formation ability of the DX120EΔrpoNΔntrC double mutant strain was decreased.The DX120EΔrpoN mutant could not use histidine, while the DX120EΔrpoNΔntrC double mutant could use histidine,but could not use proline.There was no significant difference in growth characteristics,swimming and swarming,biofilm formation and stress tolerance between DX120EΔrpoN mutant and DX120EΔrpoNΔntrC double mutant.【Conclusion】RpoN and NtrC affected the nitrate utilization,swarming ability,extracellular polysaccharide production and biofilm formation ability of strain DX120E.RpoN played a dominant role in the regulation of biological characteristics of strain DX120E, and both RpoN and NtrC were involved in the uptake and utilization of bacterial amino acids. |
| Key words: Klebsiella variicola RpoN NtrC gene knockout |
