Mycological Research Center, Fujian Agricultural and Forestry University, Fuzhou, Fujian, China.
College of Life Science, Ningde Normal University, Ningde, Fujian, China.
PLoS One. 2018 Apr 25;13(4):e0196287. doi: 10.1371/journal.pone.0196287. eCollection 2018.
Ganoderma lucidum is a medicinal mushroom that has been widely used in East Asia for the treatment of various diseases. The pharmacological activity of this fungus is primarily attributable to the polysaccharides and triterpenoids. In this study, to obtain the fruit bodies with improved content of active constituents, we examined the effect of salicylic acid (SA) and calcium ion on the biosynthesis of polysaccharides and triterpenoids by spraying the chemicals during the fruiting. To explore the underlying mechanisms for the variation, the transcripts of related genes involved in the polysaccharide and triterpenoid biosynthesis were measured. Results showed that Ca2+ had no effect on production of polysaccharides and triterpenoids, whereas SA increased triterpenoid content by 23.32%, compared to the control, but it had little influence on polysaccharide production. Interestingly, the combined induction increased polysaccharide and triterpenoid content by 9.02% and 13.61%, respectively, compared to the control. Under Ca2+ induction, the transcript of ugp gene in the polysaccharide biosynthetic pathway up-regulated in all three stages (mycelium, primordium, and fruit body), while pgm and gls gave no response in the mycelium and primordium stages, and up-regulated in the fruit body stage. Differently, six key triterpenoid biosynthetic genes including hmgr, hmgs, mvd, fps, sqs, and ls did not respond to the induction. In the case of SA and combined induction, pgm and ugp were up-regulated in all three stages, while gls showed an increased expression in the primordium stage and no response in other stages. The six triterpenoid biosynthetic genes were up-regulated in all three stages. The present study provides a useful approach to producing G. lucidum fruit bodies with high polysaccharide and triterpenoid content. This is important to the G. lucidum industry.
灵芝是一种药用蘑菇，在东亚被广泛用于治疗各种疾病。这种真菌的药理活性主要归因于多糖和三萜类化合物。在这项研究中，为了获得活性成分含量提高的子实体，我们研究了在出菇期喷洒化学物质水杨酸（SA）和钙离子对多糖和三萜类化合物生物合成的影响。为了探索变化的潜在机制，测量了与多糖和三萜类化合物生物合成相关的基因的转录本。结果表明，Ca2+ 对子实体多糖和三萜类化合物的生产没有影响，而 SA 使三萜类化合物的含量比对照增加了 23.32%，但对多糖的产生影响不大。有趣的是，联合诱导使多糖和三萜类化合物的含量分别比对照增加了 9.02%和 13.61%。在 Ca2+ 诱导下，多糖生物合成途径中的 ugp 基因在三个阶段（菌丝体、原基和子实体）均上调，而 pgm 和 gls 在菌丝体和原基阶段没有反应，仅在子实体阶段上调。不同的是，包括 hmgr、hmgs、mvd、fps、sqs 和 ls 在内的六个关键三萜类化合物生物合成基因对诱导没有反应。在 SA 和联合诱导的情况下，pgm 和 ugp 在三个阶段均上调，而 gls 在原基阶段表达增加，其他阶段没有反应。六个三萜类化合物生物合成基因在三个阶段均上调。本研究为生产多糖和三萜类化合物含量高的灵芝子实体提供了一种有用的方法。这对灵芝产业很重要。
