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LDS1-produced oxylipins are negative regulators of growth, conidiation and fumonisin synthesis in the fungal maize pathogen Fusarium verticillioides.

Scala V, Giorni P, Cirlini M, Ludovici M, Visentin I, Cardinale F, Fabbri AA, Fanelli C, Reverberi M, Battilani P, Galaverna G, Dall'Asta C - Front Microbiol (2014)

Bottom Line: Among the many enzymes responsible for oxylipin generation, Linoleate Diol Synthase 1 (LDS1) produces mainly 8-hydroperoxyoctadecenoic acid and subsequently different di-hydroxyoctadecenoic acids.In this study, we inactivated a copy of the putative LDS1 ortholog (acc.We hypothesize that oxylipins may act as regulators of gene expression in the toxigenic plant pathogen F. verticillioides, in turn causing notable changes in its phenotype.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental Biology, University of Rome "Sapienza" Rome, Italy.

ABSTRACT
Oxylipins are fatty acid-derived signaling compounds produced by all eukaryotes so far investigated; in mycotoxigenic fungi, they modulate toxin production and interactions with the host plants. Among the many enzymes responsible for oxylipin generation, Linoleate Diol Synthase 1 (LDS1) produces mainly 8-hydroperoxyoctadecenoic acid and subsequently different di-hydroxyoctadecenoic acids. In this study, we inactivated a copy of the putative LDS1 ortholog (acc. N. FVEG_09294.3) of Fusarium verticillioides, with the aim to investigate its influence on the oxylipin profile of the fungus, on its development, secondary metabolism and virulence. LC-MS/MS oxylipin profiling carried out on the selected mutant strain revealed significant quali-quantitative differences for several oxylipins when compared to the WT strain. The Fvlds1-deleted mutant grew better, produced more conidia, synthesized more fumonisins and infected maize cobs faster than the WT strain. We hypothesize that oxylipins may act as regulators of gene expression in the toxigenic plant pathogen F. verticillioides, in turn causing notable changes in its phenotype. These changes could relate to the ability of oxylipins to re-shape the transcriptional profile of F. verticillioides by inducing chromatin modifications and exerting a direct control on the transcription of secondary metabolism in fungi.

No MeSH data available.


Related in: MedlinePlus

mRNA levels of LDS1-3 (A–C) and LOX (D) at 2-15 DAI. WT, mutant (ΔFvlds1D) and COM strains of F. verticillioides were grown in FB-inducing CDYM. Relative mRNA expression is calculated by using the 2−ΔΔCt method, i.e., by normalizing gene of interest expression onto housekeeping gene expression and to their value at the time of inoculation (time zero). LDS1a and b were not discriminated in this analysis. Results are the mean (± SE) of six replicates from two independent experiments.
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Figure 2: mRNA levels of LDS1-3 (A–C) and LOX (D) at 2-15 DAI. WT, mutant (ΔFvlds1D) and COM strains of F. verticillioides were grown in FB-inducing CDYM. Relative mRNA expression is calculated by using the 2−ΔΔCt method, i.e., by normalizing gene of interest expression onto housekeeping gene expression and to their value at the time of inoculation (time zero). LDS1a and b were not discriminated in this analysis. Results are the mean (± SE) of six replicates from two independent experiments.

Mentions: As stated previously, at least four LDS genes (LDS1a and b, LDS2, and LDS3) and one gene encoding a putative 13S-LOX (based on its high similarity with LOX2 in F. oxysporum, Brodhun et al., 2013) are present in our F. verticillioides WT strain. We tested their transcript level in the WT, ΔFvlds1D and COM strains grown on CDYM by RT-qPCR. All LDS genes were strongly down-regulated in ΔFvlds1D (Figures 2A–C; LDS1a and b were not discriminated in this analysis). It is also worth mentioning that the expression of the putative 13S-LOX gene, instead, was significantly up-regulated early after inoculation (2 and 5 DAI) when compared to the WT (Figure 2D). Transcript levels of oxylipin genes in the COM strain were similar to the WT (Figures 2A–D).


LDS1-produced oxylipins are negative regulators of growth, conidiation and fumonisin synthesis in the fungal maize pathogen Fusarium verticillioides.

Scala V, Giorni P, Cirlini M, Ludovici M, Visentin I, Cardinale F, Fabbri AA, Fanelli C, Reverberi M, Battilani P, Galaverna G, Dall'Asta C - Front Microbiol (2014)

mRNA levels of LDS1-3 (A–C) and LOX (D) at 2-15 DAI. WT, mutant (ΔFvlds1D) and COM strains of F. verticillioides were grown in FB-inducing CDYM. Relative mRNA expression is calculated by using the 2−ΔΔCt method, i.e., by normalizing gene of interest expression onto housekeeping gene expression and to their value at the time of inoculation (time zero). LDS1a and b were not discriminated in this analysis. Results are the mean (± SE) of six replicates from two independent experiments.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4263177&req=5

Figure 2: mRNA levels of LDS1-3 (A–C) and LOX (D) at 2-15 DAI. WT, mutant (ΔFvlds1D) and COM strains of F. verticillioides were grown in FB-inducing CDYM. Relative mRNA expression is calculated by using the 2−ΔΔCt method, i.e., by normalizing gene of interest expression onto housekeeping gene expression and to their value at the time of inoculation (time zero). LDS1a and b were not discriminated in this analysis. Results are the mean (± SE) of six replicates from two independent experiments.
Mentions: As stated previously, at least four LDS genes (LDS1a and b, LDS2, and LDS3) and one gene encoding a putative 13S-LOX (based on its high similarity with LOX2 in F. oxysporum, Brodhun et al., 2013) are present in our F. verticillioides WT strain. We tested their transcript level in the WT, ΔFvlds1D and COM strains grown on CDYM by RT-qPCR. All LDS genes were strongly down-regulated in ΔFvlds1D (Figures 2A–C; LDS1a and b were not discriminated in this analysis). It is also worth mentioning that the expression of the putative 13S-LOX gene, instead, was significantly up-regulated early after inoculation (2 and 5 DAI) when compared to the WT (Figure 2D). Transcript levels of oxylipin genes in the COM strain were similar to the WT (Figures 2A–D).

Bottom Line: Among the many enzymes responsible for oxylipin generation, Linoleate Diol Synthase 1 (LDS1) produces mainly 8-hydroperoxyoctadecenoic acid and subsequently different di-hydroxyoctadecenoic acids.In this study, we inactivated a copy of the putative LDS1 ortholog (acc.We hypothesize that oxylipins may act as regulators of gene expression in the toxigenic plant pathogen F. verticillioides, in turn causing notable changes in its phenotype.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental Biology, University of Rome "Sapienza" Rome, Italy.

ABSTRACT
Oxylipins are fatty acid-derived signaling compounds produced by all eukaryotes so far investigated; in mycotoxigenic fungi, they modulate toxin production and interactions with the host plants. Among the many enzymes responsible for oxylipin generation, Linoleate Diol Synthase 1 (LDS1) produces mainly 8-hydroperoxyoctadecenoic acid and subsequently different di-hydroxyoctadecenoic acids. In this study, we inactivated a copy of the putative LDS1 ortholog (acc. N. FVEG_09294.3) of Fusarium verticillioides, with the aim to investigate its influence on the oxylipin profile of the fungus, on its development, secondary metabolism and virulence. LC-MS/MS oxylipin profiling carried out on the selected mutant strain revealed significant quali-quantitative differences for several oxylipins when compared to the WT strain. The Fvlds1-deleted mutant grew better, produced more conidia, synthesized more fumonisins and infected maize cobs faster than the WT strain. We hypothesize that oxylipins may act as regulators of gene expression in the toxigenic plant pathogen F. verticillioides, in turn causing notable changes in its phenotype. These changes could relate to the ability of oxylipins to re-shape the transcriptional profile of F. verticillioides by inducing chromatin modifications and exerting a direct control on the transcription of secondary metabolism in fungi.

No MeSH data available.


Related in: MedlinePlus