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Lipofuscins and sclerotial differentiation in phytopathogenic fungi
Christos D Georgiou1, Athanasios Zees
1Department of Biology, University of Patras, Patra, Greece. c.georgiou@upatras.gr
Abstract:
Lipofuscins of lipidic and proteinaceous origin were identified by their excitation and emission spectra in phytopathogenic fungal representatives of different sclerotial differentiation types. Lipofuscin pigments in Sclerotium rolfsii, Rhizoctonia solani, Sclerotinia minor and Sclerotinia sclerotiorum showed similar excitation and emission maxima (ex-em 330-450, 330-450, 330-470 and 330-470 nm, respectively). Sclerotial differentiation of these fungi was proceeded by a 4.2, 2.5, 2.7, 2.5 and 6, 2.9, 3.8, 3.1 fold increase of lipofuscin accumulation (per lipid and protein content), per respective fungus, as compared to their undifferentiated stage. Lipofuscin levels were higher in older than in younger mycelia and this phenomenon was more profound in S. rolfsii. Since lipofuscins are considered as indicators of oxidative stress, these data are in accordance with the hypothesis that suggests oxidative stress to be a common underlying factor in sclerotial differentiation of sclerotia-forming filamentous phytopathogenic fungi.
Insights
Phytopathogenic fungi accumulate lipofuscin pigments during sclerotial differentiation, indicating increased oxidative stress. This study identifies lipofuscin accumulation as a common factor in sclerotia formation across different fungal species.
Area of Science:
- Mycology
- Plant Pathology
- Biochemistry
Background:
- Lipofuscins are age-related pigments originating from oxidized lipids and proteins.
- Sclerotial differentiation is a crucial developmental process in many filamentous phytopathogenic fungi.
- Oxidative stress is hypothesized to play a role in sclerotial development.
Purpose of the Study:
- To investigate lipofuscin accumulation in phytopathogenic fungi during sclerotial differentiation.
- To determine if lipofuscin levels correlate with sclerotial development and oxidative stress.
- To compare lipofuscin profiles across different species of sclerotia-forming fungi.
Main Methods:
- Identification of lipofuscins using excitation and emission spectra.
- Quantification of lipofuscin accumulation relative to lipid and protein content.
- Comparison of lipofuscin levels in differentiated (sclerotial) and undifferentiated fungal stages.
- Analysis of lipofuscin accumulation in different age-related mycelial stages.
Main Results:
- Similar excitation and emission maxima for lipofuscins were observed in Sclerotium rolfsii, Rhizoctonia solani, Sclerotinia minor, and Sclerotinia sclerotiorum.
- Significant increases in lipofuscin accumulation (4.2 to 6-fold) occurred during sclerotial differentiation compared to undifferentiated stages.
- Lipofuscin levels were higher in older mycelia than in younger mycelia, particularly in S. rolfsii.
- Lipofuscin accumulation showed a positive correlation with sclerotial differentiation across the studied fungal species.
Conclusions:
- Lipofuscin accumulation is a common feature associated with sclerotial differentiation in phytopathogenic fungi.
- The observed increase in lipofuscins supports the hypothesis that oxidative stress is a common underlying factor in sclerotial development.
- Lipofuscins can serve as biochemical indicators of oxidative stress during the sclerotial differentiation process in these fungi.