The Velvet transcription factor PnVeA regulates necrotrophic effectors and secondary metabolism in the wheat pathogenParastagonospora nodorum

Abstract

The fungusParastagonospora nodorumcauses septoria nodorum blotch on wheat. The role of the fungal Velvet-family transcription factor VeA inP. nodorumdevelopment and virulence was investigated here. Deletion of theP. nodorum VeAortholog,PnVeA, resulted in growth abnormalities including pigmentation, abolished asexual sporulation and highly reduced virulence on wheat. Comparative RNA-Seq and RT-PCR analyses revealed that the deletion ofPnVeAalso decoupled the expression of major necrotrophic effector genes. In addition, the deletion ofPnVeAresulted in an up-regulation of four predicted secondary metabolite (SM) gene clusters. Using liquid-chromatography mass-spectrometry, it was observed that one of the SM gene clusters led to an accumulation of the mycotoxin alternariol. PnVeA is essential for asexual sporulation, full virulence, secondary metabolism and necrotrophic effector regulation.