Objective: Green synthesis of silver nanoparticles (AgNPs) has become widely practiced worldwide. In this study, AgNPs were synthesized using a hot-water extract of the edible mushroom, Pleurotus sajor-caju. 
Methods: The product, PSC-AgNPs, was characterized by using UV-Vis spectra, DLS analysis, TEM, XRD and FTIR spectrometry. To assess its antifungal activity against C. albicans, gene transcription and protein expression analyses were conducted for CaICL1 and its product, ICL using RT-qPCR and western blot, respectively.  
Results: PSC-AgNPs with an average particle size of 11.68 nm inhibited the growth of the pathogenic yeast C. albicans. MIC and MFC values were 250 mg/L and 500 mg/L, respectively. TEM images revealed that the average particle size of PSC-AgNPs was 16.8 nm, with the values for zeta potential and the polydispersity index being -8.54 mV and 0.137, respectively. XRD and FTIR spectra showed PSC-AgNPs to have a face-centered cubic (FCC) crystalline structure. The polysaccharides and amino acid residues present in P. sajor-caju extract were found to be involved in reducing Ag+ to AgNP. Both CaICL1 transcription and ICL protein expression were found to be suppressed in the cells treated with PSC-AgNPs as compared with the control.
Conclusion: Our PSC-AgNPs preparation makes for a promising antifungal agent that can downregulate isocitrate lyase.

6 / Pleurotus sajor-caju can be used to synthesize silver nanoparticles with anti-fungal activity against Candida albicans