State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No.1 Beichen West Road, Chaoyang District, Beijing, 100101, China.
College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.
World J Microbiol Biotechnol. 2024 Mar 19;40(5):136. doi: 10.1007/s11274-024-03956-6.
Photosynthetic diazotrophs expressing iron-only (Fe-only) nitrogenase can be developed into a promising biofertilizer, as it is independent on the molybdenum availability in the soil. However, the expression of Fe-only nitrogenase in diazotrophs is repressed by the fixed nitrogen of the soil, limiting the efficiency of nitrogen fixation in farmland with low ammonium concentrations that are inadequate for sustainable crop growth. Here, we succeeded in constitutively expressing the Fe-only nitrogenase even in the presence of ammonium by controlling the transcription of Fe-only nitrogenase gene cluster (anfHDGK) with the transcriptional activator of Mo nitrogenase (NifA*) in several different ways, indicating that the engineered NifA* strains can be used as promising chassis cells for efficient expression of different types of nitrogenases. When applied as a biofertilizer, the engineered Rhodopseudomonas palustris effectively stimulated rice growth, contributing to the reduced use of chemical fertilizer and the development of sustainable agriculture.
具有固氮酶的光合微生物可被开发为有前景的生物肥料，因为它不依赖于土壤中钼的可用性。然而，土壤中固定氮会抑制固氮酶在固氮微生物中的表达，限制了低浓度铵态氮农田的固氮效率，而这些农田的铵态氮不足以支持作物的可持续生长。在这里，我们通过使用钼氮酶的转录激活因子 NifA* 以几种不同的方式控制固氮酶基因簇（anfHDGK）的转录，成功地实现了固氮酶在铵态氮存在的情况下的组成型表达，这表明工程化的 NifA* 菌株可用作高效表达不同类型固氮酶的有前景的底盘细胞。当作为生物肥料应用时，工程化的沼泽红假单胞菌有效地刺激了水稻的生长，有助于减少化肥的使用和可持续农业的发展。
