Characteristics, transcriptional patterns and possible physiological significance of glycoside hydrolase family 16 members in Coprinopsis cinerea

ABSTRACT The glycoside hydrolase (GH) 16 family of Coprinopsis cinerea includes 15 members distributed in four subgroups (A1, A2, B and D) by phylogenetic analysis. The expression patterns match well with the requirement of wall-softening in the germination of basidiospores, hyphal growth and branching, primordium formation, stipe elongation, pileus expansion and autolysis. Remarkably, expression levels of different GH16 members varied with different morphogenetic events. Like orthologs of Aspergillus fumigatus GH16 glucanases (ENG2–5), which were expressed in the dormant conidia and conidiogenesis, and essential for segregation of conidia, some members such as ENG in the subgroup A1 in C. cinerea were also predominantly expressed in dormant basidiospores, primordia and maturing pilei during basidiosporogenesis. In contrast, other members in subgroup A2, subgroup B or D were dominantly expressed in the germinating basidiospores, the growing mycelia, and the elongating stipes. We did not find the members of the GH81 or GH55 family in C. cinerea genome, which was different from A. fumigatus. However, C. cinerea contains an extra three subgroups (A2, B and D) compared with A. fumigatus. These extra subgroups of GH16 family members may function as those endo-β-1,3-glucanases belonging to other GH families in the development and growth of C. cinerea.