Phospholipase D and phosphatidic acid mediate regulation in the biosynthesis of spermidine and ganoderic acids by activating GlMyb in Ganoderma lucidum under heat stress

Abstract

Polyamines are essential for all kinds of organisms and take part in the regulation of multiple biological processes. Our previous study revealed that heat stress promoted the conversion of putrescine to spermidine and subsequently promoted the accumulation of ganoderic acids (GAs). However, how heat stress affects polyamine homeostasis remains unclear. To explore the underlying mechanism by which heat stress promoted spermidine biosynthesis, we assessed the effects of signalling molecules that respond to heat stress on spermidine biosynthesis. Our data suggested that heat stress‐induced spermidine biosynthesis and GAs accumulation via a phospholipase D (PLD)‐mediated phosphatidic acid (PA) signal. Further research revealed that the transcription factor GlMyb promoted spermidine biosynthesis via regulating spermidine synthase genes (spds1 and spds2) expression by directly bonding to their promoters and it responded to heat stress and PA signal. In summary, heat stress activated GlMyb by PLD‐mediated PA signalling and subsequently induced the expression of spds1 and spds2 to promote the biosynthesis of spermidine and the accumulation of GAs. Our findings firstly reveal a detailed mechanism by which heat signalling regulates polyamine homeostasis by PLD‐mediated PA signal in fungi and provide a greater understanding of how organisms alter polyamine levels in response to environmental changes.

GlPRMT5 inhibits GlPP2C1 via symmetric dimethylation and regulates the biosynthesis of secondary metabolites in Ganoderma lucidum

“…GA was extracted and detected as previously described 22 . In brief, dried mycelial powder (200 mg) was ultrasonically extracted in 10 mL of 95% ethanol for 2 h. The mixture was centrifuged at 4000 rpm for 10 min to obtain the supernatant.…”

“…At present, based on developments in genomics and proteomics in recent years and the progress of genetic research methods, there are an increasing number of reports on the mechanism of GA biosynthesis. Previous reports have shown that signaling molecules (reactive oxygen, nitric oxide, calcium ions) and environmental factors (high temperature, nutrients, chemicals) in the GA biosynthesis play an important role in GA biosynthesis 22 – 28 , indicating that GA biosynthesis is driven by many factors coregulated. Importantly, research on these mechanisms is far from sufficient to reveal the regulatory network of the GA biosynthesis mechanism.…”