Mycology & Mushrooms

Biography

Biography: Monika Coton

Abstract

Mycophenolic acid (MPA) is a well-known mycotoxin produced by Penicillium species, in particular by the cheese related species Penicillium roqueforti. MPA biosynthetic gene cluster was recently described in Penicillium brevicompactum and P. roqueforti. In the present study, a 23.5 kb putative MPA cluster was localized in the recently available P. roqueforti FM164 genome sequence via an in silico analysis and is composed of 7 genes putatively coding for 7 proteins (MpaA, MpaB, MpaC, MpaDE, MpaF, MpaG, MpaH) highly similar in terms of gene synteny and sequence homology to the P. brevicompactum cluster. In order to confirm the involvement of this gene cluster in MPA biosynthesis, a gene silencing approach, using RNA interference targeting mpaC (coding for a putative polyketide synthase), was performed in a high MPA producing P. roqueforti strain (F43-1). In the obtained transformants, a reduced mpaC gene expression, as observed by Q-RT-PCR, was correlated with a decrease in MPA production as measured by LC-Q-TOF/MS. In parallel, mycotoxin quantification on multiple P. Roqueforti strains in our collection suggested strain dependent MPA production. The entire MPA gene cluster was therefore sequenced for P. roqueforti strains with contrasted MPA production and a 174 bp deletion in mpaC was observed in low MPA producers (below quantification level). PCRs targeting the identified deleted region were carried out on 55 strains and the obtained results showed an excellent correlation with MPA quantification. Overall, the obtained results indicated the clear involvement of mpaC gene as well as surrounding cluster in P. roqueforti MPA biosynthesis. The developed molecular tools could be useful for P. roqueforti ripening culture selection.