目的 研究镉（Cd）胁迫对灵芝菌丝生长及代谢产物积累的影响，探讨Cd胁迫影响生长和代谢产物积累的机制，为灵芝生产栽培过程中控制Cd元素提供依据。方法 在Cd质量浓度分别为0、0.5、1.0、4.0、10.0、40.0 mg/L下培养灵芝菌丝体，对其生物量积累、胞内活性氧（ROS）水平、膜氧化损伤、抗氧化酶活性及ROS调控相关酶表达量进行分析。结果 Cd质量浓度达到4.0 mg/L时，抑制菌丝生长；胞内ROS水平、H₂O₂及丙二醛（MDA）含量显著上升，分别提升了76%、46%、325%，且随着Cd质量浓度的增加呈上升趋势；NADPH氧化酶基因（NOXA）、超氧化物歧化酶基因（SOD1，SOD4）、过氧化氢酶基因（CAT）表达量显著上调。Cd质量浓度达到10.0 mg/L时抑制效果显著，菌落生长直径及发酵菌丝干质量抑制率分别为26.15%、32.78%，灵芝总三萜抑制率为33.7%，对总蛋白合成的抑制率为30.3%，对多糖抑制不显著。Cd质量浓度达到40.0 mg/L时，抗坏血酸过氧化物酶基因（APX）及谷胱甘肽过氧化物酶基因（GPX）表达量显著上调。随着Cd质量浓度的增加，SOD、CAT、APX、GPX酶活性都呈先上升后下降趋势，Cd质量浓度达到1.0 mg/L时，GPX酶活性下降，APX酶活性上升显著。外源添加diphenyleneiodonium chloride（DPI）、N-乙酰-L-半胱氨酸（NAC）、维生素C（VC）对Cd胁迫灵芝胞内清除ROS水平及降低MDA含量作用显著。结论 Cd胁迫造成灵芝菌丝产量及代谢物积累下降，可能是由于Cd离子抑制GPX酶活性下降，造成H₂O₂积累，引起ROS水平上升及膜氧化损伤，抑制菌丝生长及代谢产物积累，同时调控NOXA基因表达量上调，造成抗氧化酶活性及表达量上升来提高机体对活性氧的清除。因此在灵芝的生产过程中要控制Cd元素质量浓度小于1 mg/L。

Objective To study the effects of cadmium stress on mycelial growth and accumulation of metabolites in Ganoderma lucidum, and to explore the mechanisms affecting growth and accumulation of metabolites, and to provide evidence for controlling cadmium in the production and cultivation of G. lucidum. Methods The mycelium of G. lucidum was cultured under the conditions of heavy metal ion cadmium concentration of 0, 0.5, 1, 4, 10, and 40 mg/L, and its biomass accumulation, intracellular ROS level, membrane oxidative damage, anti-oxidant enzyme activity, and ROS regulation related enzyme expression were analyzed. Results When the concentration of cadmium reached 4 mg/L, the mycelial growth was inhibited. The levels of intracellular ROS, H₂O₂, and MDA increased significantly, increasing by 76%, 46% and 325%, respectively, and increased with the increase of cadmium concentration; The NADPH expression levels of oxidase gene (NOXA), superoxide dismutase gene (SOD1 and SOD4), and CATalase gene (CAT) were significantly up-regulated. When the cadmium concentration reached 10 mg/L, the inhibitory effect was significant. The colony growth diameter and the dry weight inhibition rate of fermentation mycelium were 26.15% and 32.78%, respectively. The total triterpenoid inhibition rate of G. lucidum was 33.7%, and the inhibition rate of total protein synthesis was 30.3%. Inhibition of polysaccharides was not significant. When the cadmium concentration reached 40 mg/L, the expression levels of Ascorbate peroxidase gene (APX) and Glutathione peroxidase gene (GPX) were significantly up-regulated. With the increase of cadmium concentration, the activities of SOD, CAT, APX, and GPX increased first and then decreased. When the concentration of cadmium reached 1 mg/L, the activity of GPX decreased and the activity of APX increased significantly. Exogenous addition of diphenyleneiodonium chloride (DPI), N-acetyl-L-cysteine (NAC) and vitamin C (VC) had significant effects on cadmium-induced G. lucidum clearance of ROS and reduction of MDA content. Conclusion Cadmium stress causes the decrease of mycelial production and metabolite accumulation of G. lucidum, which may be due to the inhibition of GPX activity by cadmium ions, resulting in the accumulation of H₂O₂, causing the increase of ROS level and membrane oxidative damage, inhibiting mycelial growth and accumulation of metabolites, and regulating NOX. Up-regulation of gene expression results in an increase in anti-oxidant enzyme activity and expression to increase the clearance of reactive oxygen species. Therefore, the cadmium content should be controlled within the range of 1 mg/L during the production process.

R286.2

吉林省科技支撑项目（20160312008ZG）；吉林省自然科学基金项目（20180101260JC）