Phosphopantetheinyl transferase (Ppt)-mediated biosynthesis of lysine, but not siderophores or DHN melanin, is required for virulence of Zymoseptoria tritici on wheat

Abstract

Zymoseptoria tritici is the causal agent of Septoria tritici blotch (STB) disease of wheat. Z. tritici is an apoplastic fungal pathogen, which does not penetrate plant cells at any stage of infection, and has a long initial period of symptomless leaf colonisation. During this phase it is unclear to what extent the fungus can access host plant nutrients or communicate with plant cells. Several important primary and secondary metabolite pathways in fungi are regulated by the post-translational activator phosphopantetheinyl transferase (Ppt) which provides an essential co-factor for lysine biosynthesis and the activities of non-ribosomal peptide synthases (NRPS) and polyketide synthases (PKS). To investigate the relative importance of lysine biosynthesis, NRPS-based siderophore production and PKS-based DHN melanin biosynthesis, we generated deletion mutants of ZtPpt. The ∆ZtPpt strains were auxotrophic for lysine and iron, non-melanised and non-pathogenic on wheat. Deletion of the three target genes likely affected by ZtPpt loss of function (Aar- lysine; Nrps1-siderophore and Pks1- melanin), highlighted that lysine auxotrophy was the main contributing factor for loss of virulence, with no reduction caused by loss of siderophore production or melanisation. This reveals Ppt, and the lysine biosynthesis pathway, as potential targets for fungicides effective against Z. tritici.

Exploring Bacterial Endophytes as Potential Biocontrol Agents Against Aspergillus parasiticus Colonisation and Aflatoxin Contamination in Maize

“…Note: a Paenibacillus sp. was reported byBaek et al (2022).Derbyshire et al (2018) studied 40 plant growth-promoting rhizobacterial strains, which produced siderophore and significantly inhibited the growth of F. oxysporum and Ralstonia solanacearum.…”

Deletion of the polyketide synthase‐encoding gene pks1 prevents melanization in the extremophilic fungus Cryomyces antarcticus

“…In a phylogenetic tree based on amino acid identity (Figure 2B), C. antarcticus PKS1 groups with PKS from other Dothideomycetes (68%–73%), and E. dermatitidis PKS1 (48%), K. petricola PKS1 (47%), and B. cinerea PKS13 (49%). For all these fungi, the requirement of the PKS for DHN melanin formation was experimentally shown 21,49,59–62 . The close relationship of CaPKS1 with these PKSs suggests that CaPKS1 is involved in DHN melanogenesis as well.…”

“…For all these fungi, the requirement of the PKS for DHN melanin formation was experimentally shown. 21 , 49 , 59 , 60 , 61 , 62 The close relationship of CaPKS1 with these PKSs suggests that CaPKS1 is involved in DHN melanogenesis as well.…”

Population-level transposable element expression dynamics influence trait evolution in a fungal crop pathogen

“…The specific biological roles of the different metabolites are poorly understood with few exceptions ( 52 , 68 ). However, individual metabolites can play major roles in species interactions with competitors or hosts ( 40 , 69 ). Similarly, TE insertions in crop plants are associated with a wide range of agronomic traits and secondary metabolites such as in tomatoes ( 4 , 70 ).…”