Molecular characterization and expression profiling of novel laccase isoenzyme genes from Fusarium solani X701, a wood-rotting ascomycete

• Four laccase isoenzyme genes were cloned from a wood-rotting ascomycete, Fusarium solani X701.
• Expression profiles implied different carbon sources modulated laccase isoenzymes expression.
• lcc4 is the responsible laccase gene for catabolizing lignin.

Fusarium solani X701 is a wood-rotting ascomycete. Four laccase isoenzyme genes, lcc1, lcc2, lcc3 and lcc4, were cloned from this fungus, expression of these genes was profiled, and their relationship with other laccases was explored. Expression profiling of the isoenzymes in different media clearly shown that lcc4 mRNA was significantly induced by lignin, suggesting that lcc4 be the responsible gene for catabolizing lignin. Expression of lcc1 was triggered by the switch from the presence to the absence of glucose, while lcc2 was significantly induced in the glucose medium. Expression levels of lcc3 were not affected by different carbon sources in the primary growth phase, but a short induction by lignin was observed in early secondary growth phase. Bioinformatical analyses revealed unique features in our isoenzymes in comparison with other laccase isoenzymes from ascomycete.