ABSTRACT
Laccases
produced by white rot fungi are involved in the degradation of lignin
and a broad diversity of other natural and synthetic molecules, having
a great potential for biotechnological applications. They are
frequently encoded by gene families, as in the basidiomycete
Trametes sp. strain I-62, from which the lcc1,
lcc2, and lcc3 laccase genes have been cloned and
sequenced. A multiplex reverse transcription-PCR method to
simultaneously study the expression of these genes was developed in
this study. The assay proved to be quick, simple, highly sensitive, and
reproducible and is particularly valuable when numerous samples are to
be analyzed and/or if the amount of initial mRNA is limited. It was
used to analyze the effect of 3,4-dimethoxybenzyl alcohol (veratryl
alcohol) and two of its isomers (2,5-dimethoxybenzyl alcohol and
3,5-dimethoxybenzyl alcohol) on differential laccase gene expression in
Trametes sp. strain I-62. These aromatic compounds produced
different induction patterns despite their chemical similarity. We
found 2,5-dimethoxybenzyl alcohol to be the best inducer of laccase
activity while also producing the highest increase in gene expression;
3,5-dimethoxybenzyl alcohol was the next best inducer. Transcript
amounts of each gene fluctuated dramatically in the presence of these
three inducers, while the total amounts of laccase mRNAs seemed to be
modulated by a coordinated regulation of the different
genes.