Abscisic acid-mediated cytosolic Ca2+ modulates triterpenoid accumulation of Ganoderma lucidum.

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Ganoderma lucidum is a mushroom widely used for its edible and medicinal properties. Primary bioactive constituents of G. lucidum are ganoderic triterpenoids (GTs), which exhibit important pharmacological activity. Abscisic acid (ABA), a plant hormone, is associated with plant growth, development, and stress responses. ABA can also affect the growth, metabolism, and physiological activities of different fungi and participates in the regulation of the tetracyclic triterpenes of some plants. Our findings indicated that ABA treatment promoted GT accumulation by regulating the gene expression levels (squalene synthase (sqs), 3-hydroxy-3-methylglutaryl-CoA reductase (hmgr), and lanosterol synthase (ls)), and also activated cytosolic Ca 2+ channels. Furthermore, under ABA mediation, exogenous Ca 2+ donors and inhibitors directly affected the cytosolic Ca 2+ concentration and related gene expression in Ca 2+ signaling. Our study also revealed that ABA-mediated cytosolic Ca 2+ played a crucial regulatory role in GT biosynthesis, accompanied by antioxidant defense modulation with increasing superoxide dismutase (SOD) activity and ascorbate peroxidase (APX) activity, and the resistance ability of O 2 •- and glutathione (GSH) contents.

灵芝是中医药宝库中的珍品，具有重要的药理学功能。作为灵芝最主要的活性物质之一，灵芝三萜含量是评价灵芝质量的重要指标。本研究旨在探讨脱落酸（ABA）介导胞内钙离子（Ca 2+ ）对灵芝三萜积累的影响。研究发现，ABA （300 μmol/L）可有效促进灵芝三萜积累，其合成途径中关键酶基因（ sqs 、 hmgr 、 ls ）表达水平随之发生变化；同时，ABA诱导可激活胞内Ca 2+ 通道并提高Ca 2+ 浓度。在ABA介导下，外源Ca 2+ 供体和抑制剂可直接影响胞内Ca 2+ 浓度及Ca 2+ 信号相关基因的表达。此外，ABA介导的Ca 2+ 在灵芝三萜的生物合成中起着关键的调节作用，并伴随抗氧化防御调节，包括超氧化物歧化酶（SOD）和抗坏血酸过氧化物酶（APX）活性、超氧阴离子自由基（O 2 ·- ）清除能力、谷胱甘肽（GSH）含量的提高。.

灵芝是中医药宝库中的珍品，具有重要的药理学功能。作为灵芝最主要的活性物质之一，灵芝三萜含量是评价灵芝质量的重要指标。本研究旨在探讨脱落酸（ABA）介导胞内钙离子（Ca 2+ ）对灵芝三萜积累的影响。研究发现，ABA （300 μmol/L）可有效促进灵芝三萜积累，其合成途径中关键酶基因（ sqs 、 hmgr 、 ls ）表达水平随之发生变化；同时，ABA诱导可激活胞内Ca 2+ 通道并提高Ca 2+ 浓度。在ABA介导下，外源Ca 2+ 供体和抑制剂可直接影响胞内Ca 2+ 浓度及Ca 2+ 信号相关基因的表达。此外，ABA介导的Ca 2+ 在灵芝三萜的生物合成中起着关键的调节作用，并伴随抗氧化防御调节，包括超氧化物歧化酶（SOD）和抗坏血酸过氧化物酶（APX）活性、超氧阴离子自由基（O 2 ·- ）清除能力、谷胱甘肽（GSH）含量的提高。