Shiitake is one of the five most cultivated edible mushrooms in the world. Its production (2 million tons) is second only to button mushroom Agaricus bisporus (Chang, 1999; Stamets, 2000). Grown mainly in East Asia, shiitake is now arousing market interest worldwide, because of its’ exotic and well-appreciated taste, and demonstrated medicinal properties (Wasser, 2005).