Nitric oxide (NO) is an important signalling molecule in stress response of organisms. We previously reported that NO decreases heat stress (HS)‐induced ganoderic acid (GA) accumulation in Ganoderma lucidum. To explore the mechanisms by which NO modulates GA biosynthesis under HS, the effect of NO on the reactive oxygen species (ROS) content was examined. The results showed that NO decreased the production of mitochondrial ROS (mitROS) by 60% under HS. Further research revealed that NO reduced the mitROS content by inhibiting aconitase (Acon) activity. The GA content in Acon‐silenced (Aconi) strains treated with NO donor did not differ significantly from that in untreated Aconi strains. To study the mechanism by which Acon activity is inhibited, the S‐nitrosylation level of Acon was determined. Biotin‐switch technology and mass spectrometry analysis were used to show that Acon is S‐nitrosylated at the Cys‐594 amino acid residue. Substitution of Cys‐594 with a Ser, which cannot be S‐nitrosylated, abolished the responsiveness of Acon to the NO‐induced reduction in its enzymatic activity. These findings demonstrate that NO inhibits Acon activity through S‐nitrosylation at Cys‐594. In summary, these findings describe mechanism by which NO regulates GA biosynthesis via S‐nitrosylation of Acon under HS condition in G. lucidum.

中文翻译：

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一氧化氮在灵芝热胁迫下通过乌头酸酶的S-亚硝基化作用来调节灵芝酸的生物合成

一氧化氮（NO）是生物体应激反应中的重要信号分子。我们以前报道，NO减小热应力（HS）在诱导的灵芝酸（GA）的积累灵芝。为了探索NO调节HS下GA生物合成的机理，研究了NO对活性氧（ROS）含量的影响。结果表明，在HS条件下，NO可使线粒体ROS（mitROS）的产量降低60％。进一步的研究表明，NO通过抑制乌头酸酶（Acon）活性降低了mitROS含量。用NO供体处理的Acon-沉默（Aconi）菌株中的GA含量与未处理的Aconi菌株中的GA含量没有显着差异。为了研究抑制Acon活性的机制，测定了Acon的S-亚硝基化水平。使用生物素开关技术和质谱分析显示，Acon在Cys-594氨基酸残基处被S-亚硝化。用无法被S-亚硝化的Ser取代Cys-594 取消了Acon对NO诱导的酶活性降低的响应。这些发现表明，NO通过在Cys-594上的S-亚硝基化抑制Acon的活性。总之，这些发现描述了NO在HS条件下通过Acon的S-亚硝基化调节GA生物合成的机制。摹。灵芝。