Identification and Functional Characterization of Adenosine Deaminase in : A Novel Potential Regulator of Nitrogen Utilization and Lipid Biosynthesis.

Adenosine deaminase (ADA) is an enzyme distributed in a wide variety of organisms that cleaves adenosine into inosine. Since inosine plays an important role in nitrogen metabolism, ADA may have a critical function in the regulation of fatty acid synthesis. However, the role of ADA in oleaginous fungi has not been reported so far. Therefore, in this study, we identified one gene encoding ADA (with ID scaffold0027.9) in the high lipid-producing fungus, WJ11, and investigated its role in cell growth, lipid production, and nitrogen metabolism by overexpressing and knockout of this gene. The results showed that knockout of the altered the efficiency of nitrogen consumption, which led to a 20% increment in the lipid content (25% of cell dry weight) of the engineered strain, while overexpression of the showed no significant differences compared with the control strain at the final growth stage; however, interestingly, it increased lipid accumulation at the early growth stage. Additionally, transcriptional analysis was conducted by RT-qPCR and our findings indicated that the deletion of activated the committed steps of lipid biosynthesis involved in acetyl-CoA carboxylase ( gene), cytosolic malic acid enzyme ( gene), and fatty acid synthases ( gene), while it suppressed the expression of AMP-activated protein kinase ( and genes), which plays a role in lipolysis, whereas the -overexpressed strain displayed reverse trends. Conclusively, this work unraveled a novel role of ADA in governing lipid biosynthesis and nitrogen metabolism in the oleaginous fungus, .