Genome editing in the edible fungus Poria cocos using CRISPR-Cas9 system integrating genome-wide off-target prediction and detection

Establishment of a genetic transformation system for cordycipitoid fungus Cordyceps chanhua

Cordyceps chanhua is a well-known edible and medicinal mushroom with a long history of use in China, and it contains a variety of secondary metabolites with interesting bioactive ingredients. However, recent researches have mainly focused on cultivation conditions, secondary metabolite compositions and pharmacological activities of C. chanhua, the lack of an efficient and stable genetic transformation system has largely limited further research on the relationship between secondary metabolites and biosynthetic gene clusters in C. chanhua. In this study, single-factor experiments were used to compare the effects of different osmotic stabilizers, enzyme concentrations and enzyme digestion times on protoplast yield, and we found that the highest yield of 5.53 × 108 protoplasts/mL was obtained with 0.7 M mannitol, 6 mg/mL snail enzyme and 4 h of enzyme digestion time, and the regeneration rate of protoplasts was up to approximately 30% using 0.7 M mannitol as an osmotic stabilizer. On this basis, a PEG-mediated genetic transformation system of C. chanhua was successfully established for the first time, which lays the foundation for further genetic transformation of C. chanhua.

Insights into the inhibition of stomach cancer MKN45 cell growth by Poria cocos ethanol-soluble extract based on MAPK/PI3K signaling pathways and components cell fishing

ETHNOPHARMACOLOGICAL RELEVANCE

Poria cocos F.A. Wolf is an edible fungus with forming sclerotia, which has the effects of promoting diuresis, exuding dampness, invigorating the spleen, and regulating the stomach. P. cocos has a high application in the clinic of traditional Chinese medicine, and some studies have indicated that P. cocos has a good effect on tumor diseases. According to ancient records and modern studies, P. cocos wine offers beneficial effects in terms of strengthening tendons and bones and anti-tumor effects.

AIM OF THE STUDY

To understand the substance composition of P. cocos ethanol-soluble extract (PESE) and then further study the effect and potential mechanism of PESE components on gastric cancer.

MATERIALS AND METHODS

In vitro and in vivo experiments were performed to detect the cell activity and apoptotic condition. Differential expression analysis and pathway enrichment were performed based on transcriptomics and were verified by real-time polymerase chain reaction and western blotting. The mice of the stomach cancer tumor model were randomly categorized into three groups. The weight and tumor volume of the mice were measured, and the pathological characteristics of tumor tissue and immunohistochemical changes were determined. Then, the main active components of PESE were detected by MKN45 cell fishing.

RESULTS

In vitro experiments showed that PESE inhibited the proliferation of MKN45 cells, but it did not induce apoptosis. Based on the transcriptome and western blotting results, the inhibition of MKN45 proliferation by PESE may be influenced by mitogen-activated protein kinase (MAPK) and phosphoinositide-3-kinase-protein kinase B (PI3K-Akt) signaling pathways. In vivo experiments showed that PESE inhibited tumor growth in mice and caused partial necrosis of tumor cells but had no toxic effect on mice. Cell fishing identified nine triterpenoids of P. cocos as the major active components of PESE.

CONCLUSIONS

The results indicated that PESE has a significant inhibitory effect on stomach cancer, and its mechanism probably commonly affects the MAPK and PI3K-Akt signaling pathways, which could be due to the triterpenoid components.

Identification of squalene epoxidase in triterpenes biosynthesis in Poria cocos by molecular docking and CRISPR-Cas9 gene editing

BACKGROUND

Squalene epoxidase is one of the rate-limiting enzymes in the biosynthetic pathway of membrane sterols and triterpenoids. The enzyme catalyzes the formation of oxidized squalene, which is a common precursor of sterols and triterpenoids.

RESULT

In this study, the squalene epoxidase gene (PcSE) was evaluated in Poria cocos. Molecular docking between PcSE and squalene was performed and the active amino acids were identified. The sgRNA were designed based on the active site residues. The effect on triterpene synthesis in P. cocos was consistent with the results from ultra-high-performance liquid chromatography-quadruplex time-of-flight-double mass spectrometry (UHPLC-QTOF-MS/MS) analysis. The results showed that deletion of PcSE inhibited triterpene synthesis. In vivo verification of PcSE function was performed using a PEG-mediated protoplast transformation approach.

CONCLUSION

The findings from this study provide a foundation for further studies on heterologous biosynthesis of P. cocos secondary metabolites.

Advances in Mechanism and Application of Molecular Breeding of Medicinal Mushrooms: A Review

With the development of molecular biology and genomics technology, mushroom breeding methods have changed from single traditional breeding to molecular breeding. Compared with traditional breeding methods, molecular breeding has the advantages of short time and high efficiency. It breaks through the restrictive factors of conventional breeding and improves the accuracy of breeding. Molecular breeding technology is gradually applied to mushroom breeding. This paper summarizes the concept of molecular breeding and the application progress of various molecular breeding technologies in mushroom breeding, in order to provide reference for future research on mushroom breeding.