XVI International Botanical Congess

When a mushroom forming fungus Coprinus congregatus is transferred to an acidic liquid medium (pH 4.1), it secretes lots of membrane-associated laccase into the culture supernatant during first 24 h. We have cloned the laccase gene fragment by the PCR technique using the copper-binding region DNAs as the primers. Total RNAs were isolated from both cultures (acidic medium culture and normal, neutral medium culture) at various time intervals, and were hybridized with the cloned laccase gene. The culture of acidic condition showed strong laccase gene expression while that of the neutral condition showed almost no siganl. Furtheremore, the laccase gene expression in the acidic culture also decreased as the enzyme activity was getting lower after 24 h.