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Effect of thiols on macroconidia of Fusarium sulphureum
Abstract:
Treatment of Fusarium sulphureum macroconidial cells with five thiols alters their morphology. Macroconidial cells incubated in dithiothreitol (DTT), dithioerythritol (DTE), or thiourea differentiate into thick-walled, chlamydospore-like cells (thiol-induced spores). These cells appear similar in size and shape to chlamydospores in the light microscope, but differ markedly in cell wall structure when viewed in the electron microscope (EM). Incubation of macroconidia with both DTT and DTE also leads to the formation of large swollen cells (giant cells) which have a parietal cytoplasm and electron-tranparent cell walls; most of these giant cells lyse within 3 to 7 days of incubation. Thiourea-induced spores are characterized by the deposition of a thick, electron-dense, extracellular layer and an accumulation of mitochondria. DTT and DTE, at the concentrations used, inhibit macroconidial germination while thiourea, mercaptoethanol, and cysteine do not. With the latter three thiols, the newly formed hyphal cells become elongated with either one or both ends swollen. Mercaptoethanol-treated cells contain an abundance of mitochondria. The DTT-induced spore differs from both macroconidia and chlamydospores with respect to cellular lipid and cell wall composition. While the thiols have different effects on the macroconidia, the fact that they all induce cell expansion suggests that they react at some common sites.
Insights
Treatment of Fusarium sulphureum macroconidia with thiols like DTT, DTE, and thiourea induces morphological changes, forming thiol-induced spores and giant cells. These thiol-induced spores exhibit distinct cell wall structures compared to natural chlamydospores.
Area of Science:
- Mycology
- Cell Biology
- Biochemistry
Background:
- Fusarium sulphureum macroconidia are fungal spores.
- Understanding fungal cell differentiation is crucial for controlling plant diseases.
Purpose of the Study:
- To investigate the morphological effects of various thiols on Fusarium sulphureum macroconidia.
- To characterize the resulting cellular structures and their differences from natural chlamydospores.
Main Methods:
- Incubation of macroconidia with five different thiols: dithiothreitol (DTT), dithioerythritol (DTE), thiourea, mercaptoethanol, and cysteine.
- Microscopic analysis (light and electron microscopy) to observe morphological and ultrastructural changes.
- Assessment of macroconidial germination and hyphal cell development.
Main Results:
- DTT, DTE, and thiourea induced the formation of thick-walled, chlamydospore-like cells (thiol-induced spores) with distinct cell wall structures.
- DTT and DTE also caused the formation of giant cells with electron-transparent walls, many of which lysed.
- Thiourea, mercaptoethanol, and cysteine promoted hyphal elongation with swollen cells, and mercaptoethanol-treated cells showed abundant mitochondria.
- DTT-induced spores differed in lipid and cell wall composition from macroconidia and chlamydospores.
- DTT and DTE inhibited germination, while thiourea, mercaptoethanol, and cysteine did not.
Conclusions:
- Thiols significantly alter Fusarium sulphureum macroconidial morphology, inducing unique cellular structures like thiol-induced spores and giant cells.
- Despite varied effects, thiols appear to act on common sites to induce cell expansion in macroconidia.
- The observed changes, particularly in cell wall composition and structure, highlight thiol-induced alterations in fungal development.