Fungal AreA is a key nitrogen metabolism transcription factor in nitrogen metabolism repression (NMR). Studies have shown that there are different ways to regulate AreA activity in yeast and filamentous ascomycetes, but inBasidiomycota, how AreA is regulated is unknown. Here, a gene fromGanoderma lucidumwith similarity tonmrAof filamentous ascomycetes was identified. The NmrA interacted with the C-terminal of AreA according to yeast two-hybrid assay. In order to determine the effect of NmrA on the AreA, 2nmrAsilenced strains ofG. lucidum, with silencing efficiencies of 76% and 78%, were constructed using an RNA interference method. SilencingnmrAresulted in a decreased content of AreA. The content of AreA innmrAi-3 andnmrAi-48 decreased by approximately 68% and 60%, respectively, compared with that in the WT in the ammonium condition. Under the nitrate culture condition, silencingnmrAresulted in a 40% decrease compared with the WT. SilencingnmrAalso reduced the stability of the AreA protein. When the mycelia were treated with cycloheximide for 6 h, the AreA protein was almost undetectable in thenmrAsilenced strains, while there was still approximately 80% of the AreA protein in the WT strains. In addition, under the nitrate culture, the content of AreA protein in the nuclei of the WT strains was significantly increased compared with that under the ammonium condition. However, whennmrAwas silenced, the content of the AreA protein in the nuclei did not change compared with the WT. Compared with the WT, the expression of the glutamine synthetase gene innmrAi-3 andnmrAi-48 strains increased by approximately 94% and 88%, respectively, under the ammonium condition, while the expression level of the nitrate reductase gene innmrAi-3 andnmrAi-48 strains increased by approximately 100% and 93%, respectively, under the nitrate condition. Finally, silencingnmrAinhibited mycelial growth and increased ganoderic acid biosynthesis. Our findings are the first to reveal that a gene fromG. lucidumwith similarity to thenmrAof filamentous ascomycetes contributes to regulating AreA, which provides new insight into how AreA is regulated inBasidiomycota.