Glutaredoxin (GRX) plays an essential role in the control of the cellular redox state and related pathways in many organisms. There is limited information on GRXs from the model nitrogen (N₂)-fixing bacterium Azorhizobium caulinodans. In the present work, we identified and performed functional analyses of monothiol and dithiol GRXs in A. caulinodans in the free-living state and during symbiosis with Sesbania rostrata. Our data show that monothiol GRXs may be very important for bacterial growth under normal conditions and in response to oxidative stress due to imbalance of the redox state in grx mutants of A. caulinodans. Functional redundancies were also observed within monothiol and dithiol GRXs in terms of different physiological functions. The changes in catalase activity and iron content in grx mutants were assumed to favor the maintenance of bacterial resistance against oxidants, nodulation, and N₂ fixation efficiency in this bacterium. Furthermore, the monothiol GRX12 and dithiol GRX34 play a collective role in symbiotic associations between A. caulinodans and Sesbania rostrata. Our study provided systematic evidence that further investigations are required to understand the importance of glutaredoxins in A. caulinodans and other rhizobia.

谷胱甘肽毒素（GRX）在许多生物体的细胞氧化还原状态及相关途径的控制中起着至关重要的作用。氮（N ₂）固定细菌拟氮唑蓝细菌的GRXs信息有限。在目前的工作中，我们确定和执行单硫醇和二硫醇GRXs的职能分析，A. caulinodans在自由生活的状态，并与共生期间田菁喙。我们的数据表明，单硫醇GRXs对于正常条件下的细菌生长以及由于氧化菌的grx突变体中氧化还原状态的失衡而对氧化应激的响应可能非常重要。。就不同的生理功能而言，在单硫醇和二硫醇GRXs中也观察到功能冗余。假定grx突变体中过氧化氢酶活性和铁含量的变化有利于维持细菌对氧化剂的抗性，结瘤和N ₂固定效率。此外，一硫醇GRX12和二硫醇GRX34在A. caulinodans和Sesbania rostrata之间的共生关联中起着集体作用。我们的研究提供了系统的证据，表明需要进一步的研究来了解戊二醛和其他根瘤菌中戊二醛的重要性。