Physiological and Molecular Characterization of Laccase Gene in Morchella Spp.

Abstract

Morchella, the true morels, is a genus of edible mushrooms having economic importance. But cultivation of Morchella on commercial scale is yet not successful. Many reasons have been asigned for this; main reasons being complex nature of sclerotia in life cycle of morels, requirement of definite nutritional and environmental parameters for sclerotia formation or/and variation in ligninolytic enzyme level during mycelial growth, sclerotia formation and fruiting body formation. In the present study two Morchella spp. namely Morchella spongiola MR 17 and Morchella sp. MR 2 were used. Growth study were conducted in different medium, differnt carbon-sources and different nitrogen- sources. Maximum growth in Morchella spongiola MR 17 was recorded in malt extract while in Morchella sp. MR 2 maximum growth was measured in yeast malt extract. MSB medium containing mannose as carbon source and sodium nitrate as nitrogen source served as the best source for growth study. Increase in growth was recorded in MSB medium supplemented with zinc and manganese ions, while decrease in growth was recorded in MSB medium supplemented with copper and cadmium ions. From the sclerotial studies conduted using various lignocellulosic substrates it can be concluded that laccase enzyme plays an important role in sclerotia formation. Maximum number of sclerotia were recorded in Morchella sp. MR 2 using wheat grains as lignocellulosic substrate after 15 days of incubation. More growth and higher laccase activity was recorded in Morchella sp. MR 2. Laccase gene of 300bp was detected in Morchella sp. MR 2 using Cu1A F and Cu2 R set of primers and it was cloned in pTZ57 R/T cloning vector and sequenced. The present study points out the important role of laccase in sclerotia formation in morels. This may help in understanding the cultivation aspects in morels.