Secondary metabolite gene clusters arrangement and conservation within the genome of Stemphylium lycopersici codes the pathways for the synthesis of specific and non-specific toxins

Abstract

The aim of this work was to study the gene clusters that code for secondary metabolites within the genome of Stemphylium lycopersici and evaluate their toxicity in plant tissue since they are probably responsible for the necrotrophic symptoms provoked by S. lycopersici on plants of the Solanaceae family. We analyzed the draft genome sequences using the antiSMASH software to identify potentially toxic molecules that might be produced by S. lycopersici, and studied the activity of secreted compounds on tomato leaflet and pepper leaves. We found more than 30 gene clusters involved in the synthesis of secondary metabolites. Stemphylium lycopersici secreted compounds that provoked necrosis on tomato leaflets as well as on pepper leaves. In conclusion, S. lycopersici have the potential to produce different secondary metabolites including host-specific and non-host-specific toxins (HST and non-HST) as well as compounds that might confer advantages for their development and survival, under certain environmental conditions. Secondary metabolite gene clusters arrangement and conservation within the genome of Stemphylium lycopersici codes the pathways for the synthesis of specific and non-specific toxins.