Abstract：
Microbial nitrogen fixation presents a viable alternative to chemical fertilizers, yet the limited colonization and specificity of naturally occurring nitrogen-fixing microorganisms present significant challenges to their widespread application. In this study, we identified a nitrogen fixation gene cluster (VNnif) in Vibrio natriegens (VN) and tested its nitrogenase activity through the acetylene reduction assay. We investigated the potential utilization of nitrogenase by incorporating the nitrogenase gene cluster from VN into plant growth-promoting rhizosphere bacteria Pseudomonas protegens CHA0 and enhancing its activity to 48.16 nmol C2H2/mg/h through promoter replacement and cluster rearrangement. The engineered strain CHA0-PVNnif was found to positively impact the growth of Arabidopsis thaliana col-0 and Triticum aestivum L. (wheat). This study expanded the role of plant growth-promoting rhizobacteria (PGPR) and provided a research foundation for enhancing nitrogenase activity.
摘要：
微生物固氮是化学肥料的可行替代品，然而，天然存在的固氮微生物的有限定殖和特异性对其广泛应用提出了重大挑战。在这项研究中,我们确定了纳氏弧菌（VN）中的固氮基因簇（VNnif），并通过乙炔还原试验测试了其固氮酶活性。我们通过将VN的固氮酶基因簇整合到植物生长促进根际细菌假单胞菌蛋白CHA0中，并通过启动子替换和簇重排将其活性增强至48.16nmolC2H2/mg/h，研究了固氮酶的潜在利用。发现工程菌株CHA0-PVNnif对拟南芥col-0和小麦（小麦）的生长产生积极影响。本研究拓展了植物促生菌(PGPR)的作用,为提高固氮酶活性提供了研究基础。
