Known as auxin which regulate the plant growth, indoleacetic acid (IAA) was also found to be synthesized in basidiomycetes Ganoderma lucidum in our previously work. In the present study, the effect of excess exogenous IAA on mycelium of G. lucidum was determined. Result shows that the mycelium growth was significantly inhibited under 10 μM IAA treatment. The transcripts of both the IAA treated group and the control group were measured by high-throughput RNAseq and a total of 1605 differentially expressed genes (DEGs) were obtained. All the DEGs were analyzed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment. “Oxidoreductase activity”, “electron transport”, “catalytic activity”, “cellular aromatic compound metabolic process” were listed as the most remarkable enrichment GO terms. The deep investigation of DEGs reveals that aldh gene which participate in the IAA biosynthesis was down-regulated whereas two IAA efflux carrier were up-regulated. KEGG pathway analysis shows that the DEGs were significantly enriched in steroid biosynthesis pathway, in which 12 genes participated in ergosterol biosynthesis were up-regulated. Excess IAA may also bring oxidative stress as the expression level of antioxidative enzymes were affected. This work provides a framework for studying the mechanisms of auxin in G. lucidum.

在我们以前的工作中，吲哚乙酸（IAA）也被发现是在担子菌灵芝中合成的，它被称为调节植物生长的生长素。在本研究中，外源性过量IAA对菌丝体效应灵芝被确定。结果表明，在10μMIAA处理下，菌丝体的生长受到显着抑制。用高通量RNAseq测量IAA治疗组和对照组的转录本，共获得1605个差异表达基因（DEG）。通过基因本体论（GO）和京都基因与基因组百科全书（KEGG）富集分析了所有DEG。“氧化还原酶活性”，“电子传输”，“催化活性”，“细胞芳香族化合物代谢过程”被列为最显着的富集GO术语。度的视角的深入研究揭示了ALDH参与IAA生物合成的基因被下调，而两个IAA外排载体被上调。KEGG通路分析表明，DEGs在类固醇生物合成通路中显着富集，其中参与麦角固醇生物合成的12个基因被上调。由于抗氧化酶的表达水平受到影响，过量的IAA也可能带来氧化应激。这项工作为研究灵芝中生长素的机制提供了一个框架。