Cloning and Characterization of Promoters of the Fungal Immunomodulatory Protein Genes from Ganoderma spp. (Agaricomycetes) and Their Response to Methyl Jasmonate and Salicylic Acid

Ganoderma mushrooms for medicinal use contain various bioactive compounds, but the genetic elements available for these medicinal mushrooms are still limited. In this study we cloned and analyzed the promoters of fungal immunomodulatory protein (FIP) genes from G. lucidum and G. atrum. FIP gene expression was induced by different concentrations of methyl jasmonate (MeJA) and salicylic acid (SA), and messenger RNA expression was detected by quantitative reverse-transcription polymerase chain reaction. The results provided 5' upstream sequences of FIP genes from G. lucidum and G. atrum. Sequence analysis showed that the FIP-glu promoter sequence contained 11 CAAT boxes, 3 TATA boxes, 3 MeJA-responsive elements, 3 MYB binding site (MBS) motifs, 1 abscisic acid responsive element, 1 TGA, 1 anaerobic inducible element, 2 circadian elements, 1 fungal elicitor, 1 meristem-specific activation element, 3 Skn-1 motifs, and several light-responsive elements. The 5' flanking region of FIP-gat included 9 CAAT boxes, 4 TATA boxes, 3 MeJA-responsive elements, 1 AuxRR core, 1 GC motif, 1 MBS, 1 fungal elicitor, 1 meristem-specific activation element, 3 Skn-1 motifs, and several light-responsive elements. On the transcriptional level, both FIP-glu and FIP-gat reached their highest expression after treatment with MeJA at 500 μmol/L. FIP-glu expression depended on the concentration of SA (0-1000 mg/L); the expression of the FIP-gat gene was highest at a concentration of 100 mg MeJA/L. This research lays the foundation to use Ganoderma mycelia as bioreactors for producing FIPs.