Abstract: For further study on the mechanism of GaSQS gene in triterpene synthesis pathway of Ganoderma lucidum and the regulation of methyl jasmonate (MeJA) on GaSQS gene expression, the paper cloned the GaSQS gene from Ganoderma amboinense with RT-PCR combined RACE technologies, then using bioinformatics to analyze the GaSQS gene and its coding protein, and used MeJA to induce the expression of GaSQS gene and so on. The results showed that the full-length of SQS gene was 1 969 bp, its ORF was 1 515 bp in length, which encoded 504 amino acids, and its molecular weight was 58.2 ku. GaSQS protein had a transmembrane domain and three conserved regions, which was a hydrophilic protein with no signal peptide;its secondary structure of GaSQS protein includes the four structures, namely α-helix (59.52%), random coil (28.37%), extended strand (8.53%) and β-turn(3.57%);The phylogenetic relationship analysis showed that SQS protein from Ganoderma amboinense was closely related to Ganoderma lucidum (ABF57213.1), its similarity coefficient was 99%. Analysis of protein interaction network by String software showed that, there were ten proteins interacting with SQS protein, all of which were important substances in terpene biosynthesis process, such as the biosynthesis of triterpenoids and sterols;the analysis of qRT-PCR showed that the expression level and yield of squalene synthase (GaSQS) were all higher in primordium and early stage of fruiting body than other stages;GaSQS protein could be induced efficiently under the different concentrations of MeJA, and the peak effect was at 200 μmol/L.

Key words: Ganoderma amboinense, Triterpenoids, GaSQS, MeJA, Clone, Induced expression

CLC Number: 

• Q786