Lae1 regulates expression of multiple secondary metabolite gene clusters in Fusarium verticillioides

National Center for Agricultural Utilization Research, Peoria, IL, United States.
Fungal Genetics and Biology (Impact Factor: 2.59). 06/2012; 49(8):602-12. DOI: 10.1016/j.fgb.2012.06.003
Source: PubMed


The filamentous fungus Fusarium verticillioides can cause disease of maize and is capable of producing fumonisins, a family of toxic secondary metabolites linked to esophageal cancer and neural tube defects in humans and lung edema in swine and leukoencephalomalacia in equines. The expression of fumonisin biosynthetic genes is influenced by broad-domain transcription factors (global regulators) and Fum21, a pathway-specific transcription factor. LaeA is a global regulator that in Aspergillus nidulans, affects the expression of multiple secondary metabolite gene clusters by modifying heterochromatin structure. Here, we employed gene deletion analysis to assess the effect of loss of a F. verticillioides laeA orthologue, LAE1, on genome-wide gene expression and secondary metabolite production. Loss of Lae1 resulted in reduced expression of gene clusters responsible for synthesis of the secondary metabolites bikaverin, fumonisins, fusaric acid and fusarins as well as two clusters for which the corresponding secondary metabolite is unknown. Analysis of secondary metabolites revealed that, in contrast to a previously described Fusarium fujikuroi lae1 mutant, bikaverin production is reduced. Fumonisin production is unchanged in the F. verticillioides lae1 mutant. Complementation of the F. verticillioides mutant resulted in increased fumonisin production.

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Available from: Philipp Wiemann, Aug 11, 2014
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    • "Analysis of SMs in the F . verticillioides LAE1 mutant revealed differences of regulation from that of in F . fujikuroi LAE1 mutant ( Wiemann et al . , 2010 ) as bikaverin production was reduced , but the amount of fumonisin B1 ( FB1 ) ( Figure 3 ) remained unchanged ( Butchko et al . , 2012 ) . Nitrogen limitation have appeared to be an essential stimulus for the activation of virulence functions in phytopathogenic fungi . The ability to metabolize a wide variety of nitrogen sources enables fungi to colonize different environmental niches and survive nutrient limitations ( Tudzynski , 2014 ) . Amino acids are required for "
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    ABSTRACT: 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.
    Frontiers in Plant Science 08/2015; 6:573. DOI:10.3389/fpls.2015.00573 · 3.95 Impact Factor
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    • "[10], [11], and later on shown to be also required for the biosynthesis of secondary metabolites in the industrially applied fungus Penicillium chrysogenum (e.g. penicillin) and the phytopathogenic fungi Fusarium fujikuroi, F. verticillioides and Cochliobolus heterostrophus, respectively [12]–[15]. Further evidence emerged that LaeA also controls numerous developmental events in fungi, such as conidiation and fruiting body formation [12]–[14]. In plant and human pathogenic fungi, LaeA has also been demonstrated to be a virulence factor [13], [14], [16], [17]. "
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    ABSTRACT: In Ascomycota the protein methyltransferase LaeA is a global regulator that affects the expression of secondary metabolite gene clusters, and controls sexual and asexual development. The common mycoparasitic fungus Trichoderma atroviride is one of the most widely studied agents of biological control of plant-pathogenic fungi that also serves as a model for the research on regulation of asexual sporulation (conidiation) by environmental stimuli such as light and/or mechanical injury. In order to learn the possible involvement of LAE1 in these two traits, we assessed the effect of deletion and overexpression of lae1 gene on conidiation and mycoparasitic interaction. In the presence of light, conidiation was 50% decreased in a Δ lae1 and 30-50% increased in lae1-overexpressing (OElae1) strains. In darkness, Δ lae1 strains did not sporulate, and the OElae1 strains produced as much spores as the parent strain. Loss-of-function of lae1 also abolished sporulation triggered by mechanical injury of the mycelia. Deletion of lae1 also increased the sensitivity of T. atroviride to oxidative stress, abolished its ability to defend against other fungi and led to a loss of mycoparasitic behaviour, whereas the OElae1 strains displayed enhanced mycoparasitic vigor. The loss of mycoparasitic activity in the Δ lae1 strain correlated with a significant underexpressionn of several genes normally upregulated during mycoparasitic interaction (proteases, GH16 ß-glucanases, polyketide synthases and small cystein-rich secreted proteins), which in turn was reflected in the partial reduction of formation of fungicidal water soluble metabolites and volatile compounds. Our study shows T. atroviride LAE1 is essential for asexual reproduction in the dark and for defense and parasitism on other fungi.
    PLoS ONE 06/2013; 8(6):e67144. DOI:10.1371/journal.pone.0067144 · 3.23 Impact Factor
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    • "Table S2 gives a list of the secondary metabolism clusters up-regulated during incompatibility. Also up-regulated was the ortholog of the Lae1 secondary metabolism regulator characterized in several fungal species (Butchko et al. 2012). "
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