The expression of the cerato-platanin gene is related to hyphal growth and chlamydospores formation in Ceratocystis platani

Cerato-platanin (CP) is a protein produced by Ceratocystis platani, the causal agent of canker stain disease of plane trees. CP is the first member of the 'cerato-platanin family', and its role as a pathogen-associated molecular pattern (PAMP), inducing defence responses both in host and nonhost plants, is established. However, the primary role of CP and its homologues in the fungal life remains unknown. In the present work, we investigated the regulation of the cp gene during the in vitro growth of C. platani in different conditions and under the effect of potential stress factors. Fungal growth and conidiogenesis were also analysed. Results showed that cp is a single-copy gene whose expression level is strictly associated with hyphal growth and with chlamydospores formation. The analysis of a 1368 bp 5'-flanking region revealed putative motifs that could be involved in the regulation of gene expression in response to stress and developmental cues. Taking into account the localization of CP in the fungal cell wall and the recently published 3D structure of the protein, our results support a role for CP in growth and developmental processes of C. platani.