The potentiality of crude proteins from a newly domesticated Iranian native medicinal mushroom Lentinus tigrinus to suppress the growth of pathogenic fungi

Introduction and Objectives: Lentinus tigrinus is a culinary-medicinal mushroom belonging to the Polyporales order, which possesses nutritious and biological activities. This study for the first time reports the antifungal potentiality of crude proteins extracted from an Iranian well-authenticated strain of this mushroom, which has been recently adapted for cultivation in artificial substrate. Materials and Methods: The pure mycelia of L. tigrinus was cultured on the malt agar medium followed by being inoculated into wheat grains supplemented with 0.18% w/v CaCO3 and 1% w/v CaSO4. A lignocellulosic substrate composed of sawdust enriched with 1% wheat bran and limes 1% w/w was formulated to support vegetative and reproductive growth of this mushroom. The soluble protein was extracted from fresh mushrooms using PBS buffer precipitated by polyethylene glycol 6000. Inhibitory effects of the precipitated protein at various concentrations were quantifiably evaluated against Verticillum dahliae and Phytophthora drechsleri. The inhibition potency towards each fungal strain was calculated using the difference in the radial growth of fungal mycelia challenged with the protein-impregnated media in comparison with the not treated pathogens. Results: The findings showed that the total amount of soluble protein was 5.06±0.9% (w/w in dry matter) based on the Bradford, while the figure was 10.7±0.8% (w/w in dry matter) using Lowry method. Among various concentrations of the L. tigrinus protein (400-2000 μg/mL), 800 μg/mL of the protein prevented the growth of V. dahliae by 47.33±2.5 % which was significantly greater than those obtained with the other concentrations (p ≤ 0.05). By contrast, the activity of the protein was apparently weaker in P. drechsleri in comparison with V. dahlia. Conclusion: The data presented in this study shows that this indigenous Iranian mushroom strain may be considered as a potential to be investigated for its biological activities, including antimicrobial effects against plant and human pathogens.

Keywords:

Iranian wild-growing Lentinus tigrinus , medicinal mushroom , antifungal activity , soluble protein