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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

Virulence analysis of the two strains of F. verticillioides (WT and ΔFvlds1D mutant). Visual appearance of cobs artificially wounded, non-inoculated (mock) and inoculated with the two strains of F. verticillioides (WT and ΔFvlds1D) (A) 2 and (B) 7 DAI at 25°C in bottles containing Hoagland's solution. (C) Severity of F. verticillioides ear attack evaluated by a visual rating scale based on the SCIA (wounding and non-wounding) method (Marin et al., 2010). (D) Abundance of fungal DNA in maize ears at different DAI, as a measure of tissue colonization. This method adopts 7 classes based on the percentage of visibly infected kernels (Disease Severity Rating: 1 = 0%-no infection; 2 = 1–3%; 3 = 4–10%; 4 = 11–25%; 5 = 26–50%, 6 = 51–75%; 7 = 76–100%).
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Figure 4: Virulence analysis of the two strains of F. verticillioides (WT and ΔFvlds1D mutant). Visual appearance of cobs artificially wounded, non-inoculated (mock) and inoculated with the two strains of F. verticillioides (WT and ΔFvlds1D) (A) 2 and (B) 7 DAI at 25°C in bottles containing Hoagland's solution. (C) Severity of F. verticillioides ear attack evaluated by a visual rating scale based on the SCIA (wounding and non-wounding) method (Marin et al., 2010). (D) Abundance of fungal DNA in maize ears at different DAI, as a measure of tissue colonization. This method adopts 7 classes based on the percentage of visibly infected kernels (Disease Severity Rating: 1 = 0%-no infection; 2 = 1–3%; 3 = 4–10%; 4 = 11–25%; 5 = 26–50%, 6 = 51–75%; 7 = 76–100%).

Mentions: Oxylipins play a significant role in fungal virulence and in the cross talk with the host (Tsitsigiannis and Keller, 2007; Brodhun et al., 2009; Christensen and Kolomiets, 2011; Scarpari et al., 2014). To assess the virulence phenotype of the ΔFvlds1D strain, we inoculated maize cobs with the mutant or the WT strain. Rapid mold development was noticeable for the ΔFvlds1D mutant, slightly slower for the WT. Cobs wounded but not inoculated did not show any sign of fungal growth (Figures 4A,B). The severity of ear rot disease symptoms was rated by a published index (Reid et al., 2002). As shown in Figure 4C, the mutant strain caused more damage than the WT at 15 DAI. qPCR aimed at quantifying fungal growth into plant tissues confirmed this result. The mutant indeed colonized the host tissue significantly faster (p < 0.01) than the WT strain at 7 DAI, whereas this difference was lost at 15 DAI (Figure 4D).


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)

Virulence analysis of the two strains of F. verticillioides (WT and ΔFvlds1D mutant). Visual appearance of cobs artificially wounded, non-inoculated (mock) and inoculated with the two strains of F. verticillioides (WT and ΔFvlds1D) (A) 2 and (B) 7 DAI at 25°C in bottles containing Hoagland's solution. (C) Severity of F. verticillioides ear attack evaluated by a visual rating scale based on the SCIA (wounding and non-wounding) method (Marin et al., 2010). (D) Abundance of fungal DNA in maize ears at different DAI, as a measure of tissue colonization. This method adopts 7 classes based on the percentage of visibly infected kernels (Disease Severity Rating: 1 = 0%-no infection; 2 = 1–3%; 3 = 4–10%; 4 = 11–25%; 5 = 26–50%, 6 = 51–75%; 7 = 76–100%).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 4: Virulence analysis of the two strains of F. verticillioides (WT and ΔFvlds1D mutant). Visual appearance of cobs artificially wounded, non-inoculated (mock) and inoculated with the two strains of F. verticillioides (WT and ΔFvlds1D) (A) 2 and (B) 7 DAI at 25°C in bottles containing Hoagland's solution. (C) Severity of F. verticillioides ear attack evaluated by a visual rating scale based on the SCIA (wounding and non-wounding) method (Marin et al., 2010). (D) Abundance of fungal DNA in maize ears at different DAI, as a measure of tissue colonization. This method adopts 7 classes based on the percentage of visibly infected kernels (Disease Severity Rating: 1 = 0%-no infection; 2 = 1–3%; 3 = 4–10%; 4 = 11–25%; 5 = 26–50%, 6 = 51–75%; 7 = 76–100%).
Mentions: Oxylipins play a significant role in fungal virulence and in the cross talk with the host (Tsitsigiannis and Keller, 2007; Brodhun et al., 2009; Christensen and Kolomiets, 2011; Scarpari et al., 2014). To assess the virulence phenotype of the ΔFvlds1D strain, we inoculated maize cobs with the mutant or the WT strain. Rapid mold development was noticeable for the ΔFvlds1D mutant, slightly slower for the WT. Cobs wounded but not inoculated did not show any sign of fungal growth (Figures 4A,B). The severity of ear rot disease symptoms was rated by a published index (Reid et al., 2002). As shown in Figure 4C, the mutant strain caused more damage than the WT at 15 DAI. qPCR aimed at quantifying fungal growth into plant tissues confirmed this result. The mutant indeed colonized the host tissue significantly faster (p < 0.01) than the WT strain at 7 DAI, whereas this difference was lost at 15 DAI (Figure 4D).

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