Sanghuangporus sanghuang Transcriptome

Sanghuangporus sanghuang (S. sanghuang) is a large wood-decaying mushroom that is considered a traditional Chinese herbal medicine because of its high medicinal value. The fundamental bioactive substances produced main-ly include flavonoids, triterpenoids, and others. The expression of some specific genes in fungi can be effectively and selectively induced by fungal elicitors. To investigate the mechanism of fungal elicitors on the metabolites of S. sanghuang, we performed the metabolic and transcriptional profiling with elicitor treatment (ET) and without elicitor treatment (WET). A correlation analysis showed significant differences in triterpenoid biosynthetic path-ways in the ET and WET groups. In addition, the structural genes associated with triterpenoids and metabolites of different triterpenoids in both groups were verified using quantitative real-time polymerase chain reaction (qRT-PCR) and high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The results dis-played that three triterpenoids betulinol, betulinic acid, and 2-hydroxyoleanolic acid were detected. After the exci-tation treatment, the level of betulinic acid reached 2.62 times that in the WET and that of 2-hydroxyoleanolic acid increased 114.67 times that in the WET. The quantitative real-time polymerase chain reaction (qRT-PCR) results of the expressions of the four genes related to secondary metabolic pathways, defense gene activation, and signal transduction showed significant variations between the ET and WET groups. Generally speaking, the results sug-gest that fungal elicitors have great potential to aggregate pentacyclic triterpenoid secondary metabolites in S. sanghuang.

鲍氏层孔菌（Sanghuangporus sanghuang, S. sanghuang）是一种大型木腐真菌，因其极高的药用价值被视为传统中药材。其核心生物活性物质主要包括黄酮类、三萜类等。真菌激发子（fungal elicitor）可有效、选择性地诱导真菌中特定基因的表达。为探究真菌激发子对鲍氏层孔菌代谢产物的调控机制，本研究设置激发子处理组（ET）与无激发子处理组（WET），分别开展代谢与转录谱分析。相关性分析结果显示，ET组与WET组在三萜类生物合成通路上存在显著差异。此外，本研究通过实时荧光定量聚合酶链反应（quantitative real-time polymerase chain reaction, qRT-PCR）与高效液相色谱-串联质谱（high-performance liquid chromatography-tandem mass spectrometry, HPLC-MS/MS），对两组中与三萜类相关的结构基因以及不同三萜类代谢产物进行了验证。结果共检测到三种三萜类化合物：白桦脂醇、白桦脂酸与2-羟基齐墩果酸。经激发子处理后，白桦脂酸的含量为WET组的2.62倍，2-羟基齐墩果酸的含量则较WET组提升114.67倍。针对4个与次生代谢通路、防御基因激活及信号转导相关的基因，qRT-PCR分析结果显示，ET组与WET组的基因表达量存在显著差异。综上，本研究结果表明，真菌激发子在鲍氏层孔菌中富集五环三萜类次生代谢产物方面具有巨大潜力。