Effects of exogenous ascorbic acid on the mycelia growth and primordia formation of Pleurotus ostreatus.

Primordia formation is the first and most critical step in the development of fruiting bodies of edible fungi. In this study, the effects of exogenous ascorbic acid (ASA) on the Pleurotus ostreatus mycelia growth and primordia formation were researched and the results showed that the growth rate of P. ostreatus mycelia was accelerated and the time of primordia formation was advanced. The protein content and ascorbate oxidase (AAO) activity analysis showed that with the increase of ASA concentration, the protein content of mycelia first decreased and then increased, and in a certain concentration range, exogenous ASA could significantly promote the activity of AAO. Further expression analysis of the development regulating genes (Pofst3 and Pofst4) as well as blue light receptor coding genes (PoWC-1 and PoWC-2) showed the expression levels of those four genes all changed after the exogenous ASA addition, which indicated that the expression changes of PoWC-1 and PoWC-2, two key genes in the light morphogenesis, might affect the expression levels of development regulating genes Pofst3 and Pofst4, so as to lead to the formation of primordia in advance.