Cloning and analysis of the photoreceptor genes Oxwc-1 and Oxwc-2 from ethnopharmacological fungus Ophiocordyceps xuefengensis.

Ophiocordyceps xuefengensis is an ethnopharmacological fungus with broad pharmacological properties. Light is a critical environmental factor for the stromata formation and development of many fungi. In this study, photomorphogenesis and blue light receptor genes were studied using a strain of O. xuefengensis. Light represses vegetative growth, but conidia linked to stromata can be observed under both light and dark conditions. Light and dark conditions had little effect on the accumulation of polysaccharides and adenosine. The genes Oxwc-1 and Oxwc-2 encoding photoreceptors of O. xuefengensis were cloned and predicted to possess polypeptides of 937 and 525 amino acids, respectively. A phylogenetic analysis based on fungal WC-1/2 supported OxWC-1 and OxWC-2 were photoreceptor. The expression of both the Oxwc-1 and Oxwc-2 genes reached a maximum after receiving light stimulation for 15 min, which might relate to the inhibition of stromata growth.

A new cordycepin-producing caterpillar fungus Ophiocordyceps xuefengensis with artificial infection to the host, cultivation of mycelia and stromata.

Caterpillar fungi have numerous pharmacological and therapeutic applications in traditional medicine, due to a variety of active chemical constituents, such as cordycepin and adenosine. It is imperative to discover new resource for artificial cultivation and biometabolite production since the traditional natural species are endangered. In this study, a new strain HACM 001 was isolated and identified as Ophiocordyceps xuefengensis by rDNA-ITS sequencing. This strain showed the potential of artificial infection to caterpillar larvae leading to mummification, as well as fermentation mycelia in liquid culture and cultivation stromata in solid medium. Eight nucleosides and nucleobases, especially cordycepin and adenosine, were determined and analyzed with HPLC-DAD-Q-TOF-MS/MS technology. Cordycepin was detected in all forms of present O. xuefengensis strain at different contents, among which the highest content (37.1 µg/g) appeared in the stromata cultivated on solid medium. The content of adenosine in mycelia and stromata, respectively, reached 1155 µg/g and 1470 µg/g. Therefore, O. xuefengensis might be an alternative source for obtaining artificial fungus-caterpillar-larvae complex and producing cordycepin and adenosine.