Secondary Metabolism and Biotrophic Lifestyle in the Tomato Pathogen Cladosporium fulvum

Jerome Collemare*, Scott Griffiths, Yuichiro Iida, Mansoor Karimi Jashni, Evy Battaglia, Russell J. Cox, Pierre J. G. M. de Wit

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

35 Citations (Scopus)

Abstract

Cladosporium fulvum is a biotrophic fungal pathogen that causes leaf mould of tomato. Analysis of its genome suggested a high potential for production of secondary metabolites (SM), which might be harmful to plants and animals. Here, we have analysed in detail the predicted SM gene clusters of C. fulvum employing phylogenetic and comparative genomic approaches. Expression of the SM core genes was measured by RT-qrtPCR and produced SMs were determined by LC-MS and NMR analyses. The genome of C. fulvum contains six gene clusters that are conserved in other fungal species, which have undergone rearrangements and gene losses associated with the presence of transposable elements. Although being a biotroph, C. fulvum has the potential to produce elsinochrome and cercosporin toxins. However, the corresponding core genes are not expressed during infection of tomato. Only two core genes, PKS6 and NPS9, show high expression in planta, but both are significantly down regulated during colonization of the mesophyll tissue. In vitro SM profiling detected only one major compound that was identified as cladofulvin. PKS6 is likely involved in the production of this pigment because it is the only core gene significantly expressed under these conditions. Cladofulvin does not cause necrosis on Solanaceae plants and does not show any antimicrobial activity. In contrast to other biotrophic fungi that have a reduced SM production capacity, our studies on C. fulvum suggest that down-regulation of SM biosynthetic pathways might represent another mechanism associated with a biotrophic lifestyle.

Original languageEnglish
Article number85877
Number of pages11
JournalPLoS ONE
Volume9
Issue number1
DOIs
Publication statusPublished - 17 Jan 2014

Keywords

  • I POLYKETIDE SYNTHASE
  • NONRIBOSOMAL PEPTIDE SYNTHETASES
  • BIOSYNTHETIC GENE-CLUSTER
  • ELSINOCHROME PHYTOTOXIN
  • CERCOSPORA-NICOTIANAE
  • PHYLOGENOMIC ANALYSIS
  • MAGNAPORTHE-GRISEA
  • ELSINOE-FAWCETTII
  • USTILAGO-MAYDIS
  • ENCODING GENES

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