2.2. Tramesan Preparation

Trametes versicolor, strain C, [26] is regularly maintained on potato dextrose agar (PDA, Difco) at 4 °C, and renewed every 60 days at the collection of the Rome Botanical Garden. T. versicolor was grown for 7 days on PDA in Petri dishes at 25 °C. After 7 days, 3 plugs of 1 cm diameter, with uniformly grown biomass (mycelium + medium), were collected and added, under sterile conditions, to 100 mL of potato dextrose broth (PDB) and agitated at 150 rpm, at 25 °C, over 14 days. The entire mass (liquid medium + mycelium) was then homogenized using a Waring blender (speed 5 for 3 pulses of 2 min each) and added at 5% v/v to PDB medium and grown over 14 days. Tramesan was purified as described by [20], then 2.3 g of lyophilized Tramesan were dissolved in 1 L of distilled sterile water. This solution was used to spray wheat plants in a greenhouse environment. Plants were treated with Tramesan at 3.3 μM as previously described [20]. Tramesan was formulated with 0.1% v/v of Tween 20 as surfactant to increase its adhesion to leaves.