Genome sequencing and secondary metabolism of the postharvest pathogen Penicillium griseofulvum

Background: Penicillium griseofulvum is associated in stored apples with blue mould, the most important postharvest disease of pome fruit. This pathogen can simultaneously produce both detrimental and beneficial secondary metabolites (SM). In order to gain insight into SM synthesis in P. griseofulvum in vitro and during disease development on apple, we sequenced the genome of P. griseofulvum strain PG3 and analysed important SM clusters. Results: PG3 genome sequence (29.3 Mb) shows that P. griseofulvum branched off after the divergence of P. oxalicum but before the divergence of P. chrysogenum. Genome-wide analysis of P. griseofulvum revealed putative gene clusters for patulin, griseofulvin and roquefortine C biosynthesis. Furthermore, we quantified the SM production in vitro and on apples during the course of infection. The expression kinetics of key genes of SM produced in infected apple were examined. We found additional SM clusters, including those potentially responsible for the synthesis of penicillin, yanuthone D, cyclopiazonic acid and we predicted a cluster putatively responsible for the synthesis of chanoclavine I. Conclusions: These findings provide relevant information to understand the molecular basis of SM biosynthesis in P. griseofulvum, to allow further research directed to the overexpression or blocking the synthesis of specific SM.

Work at the University of Torino was partially supported by the LIFE financial instrument of the European Union (Contract LIFE13 ENV/HR/000580). TG group research was partially funded by a grant from the Spanish Ministry of Economy and Competitiveness (BIO2012-37161), a grant from the Qatar National Research Fund (NPRP5-298-3-086), and a grant from the European Research Council (Grant Agreement ERC-2012-StG-310325). Work at LGC lab was partially supported by a grant from the Spanish Ministry of Economy and Innovation (AGL2011-30519-C03-01) and by the Generalitat Valenciana, Spain (PROMETEOII/2014/027). ARB is grateful to CSIC and the European Social Fund for her postdoctoral contract JAE-Doc.

Peer reviewed