Assignment of a dubious gene cluster to melanin biosynthesis in the tomato fungal pathogen Cladosporium fulvum

Abstract

Pigments and phytotoxins are crucial for the survival and spread of plant pathogenic fungi. The genome of the tomato biotrophic fungal pathogen Cladosporium fulvum contains a predicted gene cluster (CfPKS1, CfPRF1, CfRDT1 and CfTSF1) that is syntenic with the characterized elsinochrome toxin gene cluster in the citrus pathogen Elsinoë fawcettii. However, a previous phylogenetic analysis suggested that CfPks1 might instead be involved in pigment production. Here, we report the characterization of the CfPKS1 gene cluster to resolve this ambiguity. Activation of the regulator CfTSF1 specifically induced the expression of CfPKS1 and CfRDT1, but not of CfPRF1. These co-regulated genes that define the CfPKS1 gene cluster are orthologous to genes involved in 1,3-dihydroxynaphthalene (DHN) melanin biosynthesis in other fungi. Heterologous expression of CfPKS1 in Aspergillus oryzae yielded 1,3,6,8-tetrahydroxynaphthalene, a typical precursor of DHN melanin. Δcfpks1 deletion mutants showed similar altered pigmentation to wild type treated with DHN melanin inhibitors. These mutants remained virulent on tomato, showing this gene cluster is not involved in pathogenicity. Altogether, our results showed that the CfPKS1 gene cluster is involved in the production of DHN melanin and suggests that elsinochrome production in E. fawcettii likely involves another gene cluster.

The inconspicuous gatekeeper: endophytic Serendipita vermifera acts as extended plant protection barrier in the rhizosphere

“…Out of four polyketide synthase genes, BsPKS1 was most strongly induced in the presence of S. vermifera (Figs S4c, S5b; Tables S4, S5). While the role of BsPKS1 in DHN‐melanin biosynthesis requires confirmation (Griffiths et al ., ), our data indicated that the presence of S. vermifera induces melanisation in B. sorokiniana hyphae (Fig. d).…”

Antifungal Agents in Agriculture: Friends and Foes of Public Health

“…Botrytis cinerea Fruits and ornamental flowers [28] Gray mold [28] Up to 30% to 40% loss of strawberries [29] Blumeria graminis Wheat and barley [28] Mildews of grasses [28] 18% potential and 13% de facto loss of grains under current disease control [30] Colletotrichum spp. Fruits and vegetables [28] Anthracnose spots and blights [28] Losses >80% in tropical, sub-tropical and Mediterranean regions [31] Cladosporium fulvum Tomato [32] Tomato leaf mold [32] Loss of 10-25% during regular years [33] Fusarium spp.…”

The Verticillium dahliae Sho1‐MAPK pathway regulates melanin biosynthesis and is required for cotton infection

“…Melanin is produced by a broad variety of pathogenic microorganisms and its production may be stimulated in stress responses, including bacteria, fungi and helminths (Nosanchuk and Casadevall, ), but unlike the well‐characterized protective role of melanin, its roles in pathogenesis are not so clear (Howard and Valent, ; Griffiths et al ., ). Similarly, in V .…”

“…Melanin is produced by a broad variety of pathogenic microorganisms and its production may be stimulated in stress responses, including bacteria, fungi and helminths (Nosanchuk and Casadevall, 2003), but unlike the well-characterized protective role of melanin, its roles in pathogenesis are not so clear (Howard and Valent, 1996;Griffiths et al, 2018). Similarly, in V. dahliae melanin biosynthesis driven by sensor and MAPK cascades is correlated with pathogenicity in some studies (Tzima et al, 2010;Tian et al, 2014;Tian et al, 2016;Wang et al, 2016;Yu et al, 2019;Zheng et al, 2019).…”