Studies On The Phenomenon Of Mycelia Browning And The Virus In Wolfiporia Cocos

Wolfiporia cocos (Schw.) Ryv.&Gilbn., an advanced basidiomycete, is generally saprophytic or parasitical in the pinaceae plant Japanese red pine and the Masson pine root. Its underground growth sclerotium is a traditional Chinese medicine with high nutritional value and medicinal value.Yingshan and Luotian County are the major regions of Wolfiporia cocos planting in Hubei province. Mycelia browning was a frequent phenomenon during Wolfiporia cocos planting and caused the reduction of output. Eleven strains collected from different origins were taken as materials, Penicillium spp., Trichoderma spp., Aspergillus spp., Saccharomyces spp., bacterium were found in browning Wolfiporia cocos spawn by routine dilution-plate method. Contamination of other fungi and bacteria maybe is one of the inducements in mycelia browning. Polyphenoloxidase (PPO) is the key enzyme in the browning process. All strain's PPO activities were rising after mycelia browning, but the SD strain's PPO activity was comparatively lower than other strains' although it was prone to brown. There was no significant correlation between browning rate and PPO activities. Characters of Wolfiporia cocos PPO were systematically studied. The PPO activities of Wolfiporia cocos were tested under conditions of different temperature and pH. PPO activities reached to the highest when temperature at 28℃. When pH was between 4.8-5.2, the PPO activities were comparatively high. Cu²⁺, Mg²⁺, Mn²⁺, Ca²⁺ could activate the PPO activities, while Vitamin C, AgNO₃, NaSO₃ could inhibit the PPO activities. Double stranded RNA (dsRNA) was found in both browning and health strains, but no virus-like particle was found under electron microscope.