Development of a 2A peptide-based multigene expression system and its application for enhanced production of ganoderic acids in Ganoderma lucidum.

Ganoderma has received much attention for its medicinal value, but the manipulation of multiple genes remains a challenge, hindering the genetic engineering of this species for the development of cell factories. Here, we first showed that the presence of an intron is necessary for the efficient expression of the endogenous cDNA of carboxin-resistant gene (cbx) in G. lucidum. Then, the self-cleaving function of 2 A peptide was investigated in G. lucidum by linking cbx cDNA to the codon-optimized hygromycin B-resistant gene (ophph) using the 2A-peptide sequence. The results showed that cbx cDNA and ophph can be successfully expressed in G. lucidum in a bicistronic manner from a single transcript. Moreover, the expression of both genes was not affected by the order within the 2 A cassette. In addition, simultaneous expression of cbx cDNA, ophph, and codon-optimized yellow fluorescent protein gene (opyfp) was conducted for the first time in G. lucidum using the 2 A peptide-based approach. The developed method was successfully applied to express both cDNA of the 3-hydroxy-3-methylglutaryl coenzyme A reductase (hmgr) and squalene epoxidase gene (se) for enhanced production of ganoderic acids (GAs) in G. lucidum. The engineered strain produced the maximum content of GA-Mk, GA-T, GA-S, and GA-Me were 26.56±3.53,39.58±3.75, 16.54±2.16, and 19.1±1.87 µg/100 mg dry weight, respectively. These values were 3.85-, 4.74-, 3.65-, and 3.23-fold higher than those produced by the control strain. The developed method will be useful for the manipulation of complex metabolic or regulatory pathways involving multiple genes in Ganoderma.

Impact of perceived value in virtual brand communities on purchase intention of domestic electric vehicles.

The consumption value seems to be insufficient to explain consumers' domestic electric vehicle purchase behaviour, especially in a highly competitive global environment. This study aims to investigate how consumer ethnocentrism and perceived interactivity influence consumption value and pro-environmental value, subsequently affecting attitude and intention. A total of 353 valid questionnaires were collected through convenience sampling in Xuzhou, China, and the partial least square (PLS) path modelling approach was performed to test the hypotheses. The results show that consumer ethnocentrism and perceived interactivity positively influence function value, emotional value, and social value; perceived interactivity also positively influences altruistic value, biospheric value, and collectivistic value. Function value, social value, and collectivistic value positively influence attitude; however, emotional value, altruistic value and biospheric value did not find a correlation with attitude. Furthermore, attitude positively influences intention to adopt domestic electric vehicles. Finally, the theoretical and practical implications, as well as limitations were discussed accordingly.