The Fungal Phytotoxin Alternariol 9-Methyl Ether and Some of Its Synthetic Analogues Inhibit the Photosynthetic Electron Transport Chain

Demuner, Antônio J.; Barbosa, Luiz Cláudio de Almeida; Miranda, Ana Cristina Mendes; Geraldo, Guilherme Carvalho; Silva, Cleiton Moreira da; Giberti, Samuele; Bertazzini, Michele; Forlani, Giuseppe

doi:10.1021/np4005882

Cited by 53 publications

(22 citation statements)

References 44 publications

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“…Interestingly, AME has been reported to suppress cyanobacterial growth by inhibiting the photosynthetic electron transport chain (79). In this study, we showed that the virulence of ⌬SnPKS19 against wheat leaves in vitro is comparable to that of the wild type; thus, AOH is unlikely to play a role in pathogenicity.…”

Section: Discussionmentioning

confidence: 56%

SnPKS19 Encodes the Polyketide Synthase for Alternariol Mycotoxin Biosynthesis in the Wheat Pathogen Parastagonospora nodorum

Chooi

Muria-Gonzalez

Mead

et al. 2015

Appl Environ Microbiol

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b Alternariol (AOH) is an important mycotoxin from the Alternaria fungi. AOH was detected for the first time in the wheat pathogen Parastagonospora nodorum in a recent study. Here, we exploited reverse genetics to demonstrate that SNOG_15829 (SnPKS19), a close homolog of Penicillium aethiopicum norlichexanthone (NLX) synthase gene gsfA, is required for AOH production. We further validate that SnPKS19 is solely responsible for AOH production by heterologous expression in Aspergillus nidulans. The expression profile of SnPKS19 based on previous P. nodorum microarray data correlated with the presence of AOH in vitro and its absence in planta. Subsequent characterization of the ⌬SnPKS19 mutants showed that SnPKS19 and AOH are not involved in virulence and oxidative stress tolerance. Identification and characterization of the P. nodorum SnPKS19 cast light on a possible alternative AOH synthase gene in Alternaria alternata and allowed us to survey the distribution of AOH synthase genes in other fungal genomes. We further demonstrate that phylogenetic analysis could be used to differentiate between AOH synthases and the closely related NLX synthases. This study provides the basis for studying the genetic regulation of AOH production and for development of molecular diagnostic methods for detecting AOH-producing fungi in the future.

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Section: Discussionmentioning

confidence: 56%

SnPKS19 Encodes the Polyketide Synthase for Alternariol Mycotoxin Biosynthesis in the Wheat Pathogen Parastagonospora nodorum

Chooi

Muria-Gonzalez

Mead

et al. 2015

Appl Environ Microbiol

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“…Fusicoccin (Figure 5 ) [ Fusicoccum ( Phomopsis ) amygdali ] irreversibly activated the plant plasma membrane H + -ATPase (Paiardini et al, 2014 ). Alternariol (Figure 2 ) and monomethyl alternariol are natural phytotoxins, produced by Nimbya and Alternaria , inhibited the electron transport chain (Demuner et al, 2013 ). Cerulenin (Figure 5 ) ( Cephalosporium cerulens ) inhibited de novo fatty acid synthesis in plastids (Laskay et al, 1985 ).…”

Section: Phytopathogenic Fungimentioning

confidence: 99%

Secondary metabolites in fungus-plant interactions

2015

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Fungi and plants are rich sources of thousands of secondary metabolites. The genetically coded possibilities for secondary metabolite production, the stimuli of the production, and the special phytotoxins basically determine the microscopic fungi-host plant interactions and the pathogenic lifestyle of fungi. The review introduces plant secondary metabolites usually with antifungal effect as well as the importance of signaling molecules in induced systemic resistance and systemic acquired resistance processes. The review also concerns the mimicking of plant effector molecules like auxins, gibberellins and abscisic acid by fungal secondary metabolites that modulate plant growth or even can subvert the plant defense responses such as programmed cell death to gain nutrients for fungal growth and colonization. It also looks through the special secondary metabolite production and host selective toxins of some significant fungal pathogens and the plant response in form of phytoalexin production. New results coming from genome and transcriptional analyses in context of selected fungal pathogens and their hosts are also discussed.

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“…AOH facilitated the infection and colonization of A. alternata on tomato, citrus and apple by the addition of AOH to pksI -deletion mutant, but the chemical alone exhibited no phytotoxin in wheat leaves and seed germination [10,11]. Correspondingly, AME enabled the inhibition of photosynthetic electron transport in extracted spinach chloroplasts [12].…”

Section: Introductionmentioning

confidence: 99%

Effects of Essential Oil Citral on the Growth, Mycotoxin Biosynthesis and Transcriptomic Profile of Alternaria alternata

Wang

Jiang

Wang

et al. 2019

Toxins

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Alternaria alternata is a critical phytopathogen that causes foodborne spoilage and produces a polyketide mycotoxin, alternariol (AOH), and its derivative, alternariol monomethyl ether (AME). In this study, the inhibitory effects of the essential oil citral on the fungal growth and mycotoxin production of A. alternata were evaluated. Our findings indicated that 0.25 μL/mL (222.5 μg/mL) of citral completely suppressed mycelial growth as the minimum inhibitory concentration (MIC). Moreover, the 1/2MIC of citral could inhibit more than 97% of the mycotoxin amount. Transcriptomic profiling was performed by comparative RNA-Seq analysis of A. alternata with or without citral treatment. Out of a total of 1334 differentially expressed genes (DEGs), 621 up-regulated and 713 down-regulated genes were identified under citral stress conditions. Numerous DEGs for cell survival, involved in ribosome and nucleolus biogenesis, RNA processing and metabolic processes, and protein processing, were highly expressed in response to citral. However, a number of DEGs responsible for the metabolism of several carbohydrates and amino acids, sulfate and glutathione metabolism, the metabolism of xenobiotics and transporter activity were significantly more likely to be down-regulated. Citral induced the disturbance of cell integrity through the disorder of gene expression, which was further confirmed by the fact that exposure to citral caused irreversibly deleterious disruption of fungal spores and the inhibition of ergosterol biosynthesis. Citral perturbed the balance of oxidative stress, which was likewise verified by a reduction of total antioxidative capacity. In addition, citral was able to modulate the down-regulation of mycotoxin biosynthetic genes, including pksI and omtI. The results provide new insights for exploring inhibitory mechanisms and indicate citral as a potential antifungal and antimytoxigenic alternative for cereal storage.

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The Fungal Phytotoxin Alternariol 9-Methyl Ether and Some of Its Synthetic Analogues Inhibit the Photosynthetic Electron Transport Chain

Cited by 53 publications

References 44 publications

SnPKS19 Encodes the Polyketide Synthase for Alternariol Mycotoxin Biosynthesis in the Wheat Pathogen Parastagonospora nodorum

SnPKS19 Encodes the Polyketide Synthase for Alternariol Mycotoxin Biosynthesis in the Wheat Pathogen Parastagonospora nodorum

Secondary metabolites in fungus-plant interactions

Effects of Essential Oil Citral on the Growth, Mycotoxin Biosynthesis and Transcriptomic Profile of Alternaria alternata

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