Preliminary exploration of the effects of oxidative stress on sclerotial formation of wild Morchella in northern Shaanxi
In order to understand the effects of oxidative stress on sclerotial formation of wild Morchella in northern Shaanxi,the influences of temperature,pH,H2O2,ascorbic acidon(strong antioxidant),sodium benzoate(hydroxyl radical scavengers)and L-cysteine(mercapto compounds)on mycelial growth and sclerotial formation in Morchella were studied by plate culture method.The quantity of H2O2 and catalase activity of mycelia and sclerotia were measured.The results showed that the optimal temperature and pH value for sclerotial formation were 20℃ and 6,respectively.Optimum quantity of H2O2 in culture medium might cause intracellular oxidative stress and promote sclerotial development.But the reactive oxygen radical scavengers can reduce fungal intracellular oxidative stress and then restrain the sclerotial occurrence.Ascorbic acidon,sodium benzoate and L-cysteine all can inhibit the mycelial growth and sclerotial occurrence,and the inhibition was enhanced with the increase of tested agents.Although the quantity of H2O2 in sclerotia cells was lower than that in mycelia,catalase activity had the opposite effect.Therefore,changes in external conditions can lead to changes in the concentration of reactive oxygen species(ROS)in mycelial cells,and the increase of reactive oxygen species to a certain concentration will promote oxidative stress in the cell,and then mycelium cells will differentiate into sclerotium.