Vinylidene fluoride (VDF) is one of the major fluorinated monomers. Currently, it is produced via the pyrolysis of 1-chloro-1,1-difluoroethane at above 650 °C without any catalyst. Herein, we propose that metal fluorides are promising catalysts that selectively promote the pyrolysis at 300–450 °C. With various metal fluorides as the catalysts, the conversion rate increases with the amount of acidic sites, which is also reinforced by the Bader charges q. The affinity to Cl of the metal fluorides is responsible for the selectivity. However, the high affinity to Cl also leads to the chlorination of metal fluorides forming metal chlorides followed by the deactivation of the catalyst. Different from other metal fluorides, F defects play a major role in the performance of AlF3. With an increase in F defects, the selectivity changes from vinylidene chlorofluoride (dehydrofluorination) to VDF (dehydrochlorination), which further confirms the role of affinity to Cl in the selectivity.

Phospholipid-mediated signal transduction plays a key role in responses to environmental changes, but little is known about the role of phospholipid signalling in microorganisms. Heat stress (HS) is one of the most important environmental factors. Our previous study found that HS could induce the biosynthesis of the secondary metabolites, ganoderic acids (GA). Here, we performed a comprehensive mass spectrometry-based analysis to investigate HS-induced lipid remodelling in Ganoderma lucidum. In particular, we observed a significant accumulation of phosphatidic acid (PA) on HS. Further genetic tests in which pld-silencing strains were constructed demonstrated that the accumulation of PA is dependent on HS-activated phospholipase D (PLD) hydrolysing phosphatidylethanolamine. Furthermore, we determined the role of PLD and PA in HS-induced secondary metabolism in G. lucidum. Exogenous 1-butanol, which decreased PLD-mediated formation of PA, reverses the increased GA biosynthesis that was elicited by HS. The pld-silenced strains partly blocked HS-induced GA biosynthesis, and this block can be reversed by adding PA. Taken together, our results suggest that PLD and PA are involved in the regulation of HS-induced secondary metabolism in G. lucidum. Our findings provide key insights into how microorganisms respond to heat stress and then consequently accumulate secondary metabolites by phospholipid remodelling.

Ganoderma lucidum has become a potential model system for evaluating how environmental factors regulate the secondary metabolism of basidiomycetes. Heat stress (HS) is one of the most important environmental factors. It was previously reported that HS could induce the biosynthesis of ganoderic acids (GA). In this study, we found that HS increased GA biosynthesis and also significantly increased cell membrane fluidity. Furthermore, our results showed that addition of the membrane rigidifier dimethylsulfoxide (DMSO) could revert the increased GA biosynthesis elicited by HS. These results indicate that an increase in membrane fluidity is associated with HS-induced GA biosynthesis. Further evidence showed that the GA content was decreased in D9des-silenced strains and could be reverted to WT levels by addition of the membrane fluidizer benzyl alcohol (BA). In contrast, GA content was increased in D9des-overexpression strains and could be reverted to WT levels by the addition of DMSO. Furthermore, both membrane fluidity and GA biosynthesis induced by HS could be reverted by DMSO in WT and D9des-silenced strains. To the best of our knowledge, this is the first report demonstrating that membrane fluidity is involved in the regulation of heat stress induced secondary metabolism in filamentous fungi.

This study aimed to identify suitable reference genes under three chemical inducers, methyl jasmonate (MeJA), salicylic acid (SA) and hydrogen peroxide (HO) in Ganoderma lucidum. In this study, expression stabilities of 14 candidate reference genes had been validated. Four algorithms were used: geNorm, NormFinder, BestKeeper, and RefFinder. Our results showed that, in short time, UCE2 (ubiquitin conjugating enzyme) was the most stable gene both in MeJA and HO treatments, ACTIN (beta-actin) was the most suitable reference gene for SA treatment. ACTIN/UCE2 were considered the most suitable genes to normalize in MeJA, SA and HO conditions. In long time, PP2A (protein phosphatase 2A regulatory subunit) was the most stable gene in MeJA and SA treatments, UCE2 was the most suitable reference gene for HO treatment. PP2A/UBQ1 (polyubiquitin 1) were considered the most suitable genes to normalize in MeJA, SA and HO conditions. Furthermore, target gene, oxidosqualene cyclase (osc), was selected to validate the most and least stable reference genes under different treatments. Our work provided a better support to study the regulatory mechanism of MeJA, SA and HO on biological functions.

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