AZC_2928 gene (GenBank accession no. BAF88926.1) of Azorhizobium caulinodans ORS571 has sequence homology to 2,3-aminomutases. However, its function is unknown. In this study, we are for the first time to knock out the gene completely in A. caulinodans ORS571 using the current advanced genome editing tool, CRISPR/Cas9. Our results show that the editing efficiency is 34% and AZC_2928 plays an extremely important role in regulating the formation of chemotaxis and biofilm. CRISPR/Cas9 knockout of AZC_2928 (△AZC_2928) significantly enhanced chemotaxis and biofilm formation. Both chemotaxis and biofilm formation play an important role in nitrogen-fixing bacteria and their interaction with their host plants. Interestingly, AZC_2928 did not affect the motility of A. caulinodans ORS571 and the nodulation formation in their natural host plant, Sesbania rostrata. Due to rhizobia needing to form bacteroids for symbiotic nitrogen fixation in mature nodules, AZC_2928 might have a direct influence on nitrogen fixation efficiency rather than the number of nodulations.

中文翻译：

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CRISPR / Cas9基因组编辑显示了AZC_2928基因在植物固氮细菌中的重要作用。

AZC _2928基因（GenBank登录号。BAF88926.1）Azorhizobium caulinodans ORS571具有序列同源性的2,3-氨基变位酶。但是，其功能未知。在这项研究中，我们第一次使用当前先进的基因组编辑工具CRISPR / Cas9完全敲除caulinodans ORS571中的基因。我们的结果表明，编辑效率为34％，AZC_2928在调节趋化性和生物膜的形成中起着极其重要的作用。AZC_2928（△AZC_2928）的CRISPR / Cas9敲除显着增强了趋化性和生物膜形成。趋化性和生物膜的形成在固氮细菌及其与寄主植物的相互作用中都起着重要作用。有趣的是，AZC_2928并没有影响其自然寄主植物Sesbania rostrata中的A. caulinodans ORS571的运动性和结瘤形成。由于根瘤菌需要形成类杆菌以在成熟结节中进行共生固氮，因此AZC_2928可能直接影响固氮效率，而不是结瘤次数。