Activity Assay of Amylase and Xylanase is Available for Quantitative Assessment of Strain Aging in Cultivated Culinary-Medicinal Morchella Mushrooms (Ascomycotina).

Strain aging has been mainly contributing to the "uncertainty" of Morchella farming. The situation calls for urgent quantitative assessment of strain aging in cultivated Morchella mushrooms. In this paper, systemic senescence of the productive strains of M. eximia, M. importuna, and M. sextelata was achieved through successive subculturing to provide subcultures with different degree of aging for further studies. Then the quantitative assessment of morel strain aging was conducted by activity assay of amylase and xylanase using dinitrosalicylic acid (DNS) method. The results suggested that both activity of amylase and xylanase decreased along with the rise of subculture times. Meanwhile, the correlation between xylanase activity and time of subculturing in the tested morel strains was higher than that of amylase assay. Consequently, assay of amylase and xylanase activity by DNS method can be used in the quantitative assessment of morel strain aging, and assay of xylanase activity is the better alternative. The work will improve the settlement of "uncertainty" in the morel industry and thus be beneficial for stable development of morel farming.